Merge branch 'master' into parse_null_or_empty

.gitignore

@@ -13,3 +13,5 @@ doc/api/
 
 .idea
 .dart_tool
+
+.vscode/

example/main.dart

@@ -1,17 +1,22 @@
-import 'package:http/http.dart' as http;
+import 'dart:io';
+
+import 'package:http/io_client.dart';
 import 'package:webfeed/webfeed.dart';
 
 void main() async {
-  var client = http.Client();
+  final client = IOClient(HttpClient()
+    ..badCertificateCallback =
+        ((X509Certificate cert, String host, int port) => true));
 
   // RSS feed
-  var response = await client
-      .get('https://developer.apple.com/news/releases/rss/releases.rss');
+  var response = await client.get(
+      Uri.parse('https://developer.apple.com/news/releases/rss/releases.rss'));
   var channel = RssFeed.parse(response.body);
   print(channel);
 
   // Atom feed
-  response = await client.get('https://www.theverge.com/rss/index.xml');
+  response =
+      await client.get(Uri.parse('https://www.theverge.com/rss/index.xml'));
   var feed = AtomFeed.parse(response.body);
   print(feed);
 

lib/domain/atom_category.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class AtomCategory {
-  final String term;
-  final String scheme;
-  final String label;
+  final String? term;
+  final String? scheme;
+  final String? label;
 
   AtomCategory(this.term, this.scheme, this.label);
 

lib/domain/atom_feed.dart

@@ -4,24 +4,24 @@ import 'package:webfeed/domain/atom_item.dart';
 import 'package:webfeed/domain/atom_link.dart';
 import 'package:webfeed/domain/atom_person.dart';
 import 'package:webfeed/util/datetime.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class AtomFeed {
-  final String id;
-  final String title;
-  final DateTime updated;
-  final List<AtomItem> items;
+  final String? id;
+  final String? title;
+  final DateTime? updated;
+  final List<AtomItem>? items;
 
-  final List<AtomLink> links;
-  final List<AtomPerson> authors;
-  final List<AtomPerson> contributors;
-  final List<AtomCategory> categories;
-  final AtomGenerator generator;
-  final String icon;
-  final String logo;
-  final String rights;
-  final String subtitle;
+  final List<AtomLink>? links;
+  final List<AtomPerson>? authors;
+  final List<AtomPerson>? contributors;
+  final List<AtomCategory>? categories;
+  final AtomGenerator? generator;
+  final String? icon;
+  final String? logo;
+  final String? rights;
+  final String? subtitle;
 
   AtomFeed({
     this.id,
@@ -41,15 +41,16 @@ class AtomFeed {
 
   factory AtomFeed.parse(String xmlString) {
     var document = XmlDocument.parse(xmlString);
-    var feedElement = findFirstElement(document, 'feed');
+    var feedElement = document.findElements('feed').firstOrNull;
     if (feedElement == null) {
       throw ArgumentError('feed not found');
     }
 
     return AtomFeed(
-      id: findFirstElement(feedElement, 'id')?.text,
-      title: findFirstElement(feedElement, 'title')?.text,
-      updated: parseDateTime(findFirstElement(feedElement, 'updated')?.text),
+      id: feedElement.findElements('id').firstOrNull?.text,
+      title: feedElement.findElements('title').firstOrNull?.text,
+      updated:
+          parseDateTime(feedElement.findElements('updated').firstOrNull?.text),
       items: feedElement
           .findElements('entry')
           .map((e) => AtomItem.parse(e))
@@ -70,12 +71,14 @@ class AtomFeed {
           .findElements('category')
           .map((e) => AtomCategory.parse(e))
           .toList(),
-      generator:
-          AtomGenerator.parse(findFirstElement(feedElement, 'generator')),
-      icon: findFirstElement(feedElement, 'icon')?.text,
-      logo: findFirstElement(feedElement, 'logo')?.text,
-      rights: findFirstElement(feedElement, 'rights')?.text,
-      subtitle: findFirstElement(feedElement, 'subtitle')?.text,
+      generator: feedElement
+          .findElements('generator')
+          .map((e) => AtomGenerator.parse(e))
+          .firstOrNull,
+      icon: feedElement.findElements('icon').firstOrNull?.text,
+      logo: feedElement.findElements('logo').firstOrNull?.text,
+      rights: feedElement.findElements('rights').firstOrNull?.text,
+      subtitle: feedElement.findElements('subtitle').firstOrNull?.text,
     );
   }
 }

lib/domain/atom_generator.dart

@@ -1,16 +1,13 @@
 import 'package:xml/xml.dart';
 
 class AtomGenerator {
-  final String uri;
-  final String version;
-  final String value;
+  final String? uri;
+  final String? version;
+  final String? value;
 
   AtomGenerator(this.uri, this.version, this.value);
 
   factory AtomGenerator.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     var uri = element.getAttribute('uri');
     var version = element.getAttribute('version');
     var value = element.text;

lib/domain/atom_item.dart

@@ -4,24 +4,24 @@ import 'package:webfeed/domain/atom_person.dart';
 import 'package:webfeed/domain/atom_source.dart';
 import 'package:webfeed/domain/media/media.dart';
 import 'package:webfeed/util/datetime.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class AtomItem {
-  final String id;
-  final String title;
-  final DateTime updated;
+  final String? id;
+  final String? title;
+  final DateTime? updated;
 
-  final List<AtomPerson> authors;
-  final List<AtomLink> links;
-  final List<AtomCategory> categories;
-  final List<AtomPerson> contributors;
-  final AtomSource source;
-  final String published;
-  final String content;
-  final String summary;
-  final String rights;
-  final Media media;
+  final List<AtomPerson>? authors;
+  final List<AtomLink>? links;
+  final List<AtomCategory>? categories;
+  final List<AtomPerson>? contributors;
+  final AtomSource? source;
+  final String? published;
+  final String? content;
+  final String? summary;
+  final String? rights;
+  final Media? media;
 
   AtomItem({
     this.id,
@@ -41,9 +41,9 @@ class AtomItem {
 
   factory AtomItem.parse(XmlElement element) {
     return AtomItem(
-      id: findFirstElement(element, 'id')?.text,
-      title: findFirstElement(element, 'title')?.text,
-      updated: parseDateTime(findFirstElement(element, 'updated')?.text),
+      id: element.findElements('id').firstOrNull?.text,
+      title: element.findElements('title').firstOrNull?.text,
+      updated: parseDateTime(element.findElements('updated').firstOrNull?.text),
       authors: element
           .findElements('author')
           .map((e) => AtomPerson.parse(e))
@@ -58,11 +58,14 @@ class AtomItem {
           .findElements('contributor')
           .map((e) => AtomPerson.parse(e))
           .toList(),
-      source: AtomSource.parse(findFirstElement(element, 'source')),
-      published: findFirstElement(element, 'published')?.text,
-      content: findFirstElement(element, 'content')?.text,
-      summary: findFirstElement(element, 'summary')?.text,
-      rights: findFirstElement(element, 'rights')?.text,
+      source: element
+          .findElements('source')
+          .map((e) => AtomSource.parse(e))
+          .firstOrNull,
+      published: element.findElements('published').firstOrNull?.text,
+      content: element.findElements('content').firstOrNull?.text,
+      summary: element.findElements('summary').firstOrNull?.text,
+      rights: element.findElements('rights').firstOrNull?.text,
       media: Media.parse(element),
     );
   }

lib/domain/atom_link.dart

@@ -1,11 +1,11 @@
 import 'package:xml/xml.dart';
 
 class AtomLink {
-  final String href;
-  final String rel;
-  final String type;
-  final String hreflang;
-  final String title;
+  final String? href;
+  final String? rel;
+  final String? type;
+  final String? hreflang;
+  final String? title;
   final int length;
 
   AtomLink(
@@ -25,7 +25,7 @@ class AtomLink {
     var hreflang = element.getAttribute('hreflang');
     var length = 0;
     if (element.getAttribute('length') != null) {
-      length = int.parse(element.getAttribute('length'));
+      length = int.parse(element.getAttribute('length')!);
     }
     return AtomLink(href, rel, type, hreflang, title, length);
   }

lib/domain/atom_person.dart

@@ -1,18 +1,18 @@
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class AtomPerson {
-  final String name;
-  final String uri;
-  final String email;
+  final String? name;
+  final String? uri;
+  final String? email;
 
   AtomPerson({this.name, this.uri, this.email});
 
   factory AtomPerson.parse(XmlElement element) {
     return AtomPerson(
-      name: findFirstElement(element, 'name')?.text,
-      uri: findFirstElement(element, 'uri')?.text,
-      email: findFirstElement(element, 'email')?.text,
+      name: element.findElements('name').firstOrNull?.text,
+      uri: element.findElements('uri').firstOrNull?.text,
+      email: element.findElements('email').firstOrNull?.text,
     );
   }
 }

lib/domain/atom_source.dart

@@ -1,10 +1,10 @@
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class AtomSource {
-  final String id;
-  final String title;
-  final String updated;
+  final String? id;
+  final String? title;
+  final String? updated;
 
   AtomSource({
     this.id,
@@ -13,13 +13,10 @@ class AtomSource {
   });
 
   factory AtomSource.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return AtomSource(
-      id: findFirstElement(element, 'id')?.text,
-      title: findFirstElement(element, 'title')?.text,
-      updated: findFirstElement(element, 'updated')?.text,
+      id: element.findElements('id').firstOrNull?.text,
+      title: element.findElements('title').firstOrNull?.text,
+      updated: element.findElements('updated').firstOrNull?.text,
     );
   }
 }

lib/domain/dublin_core/dublin_core.dart

@@ -1,25 +1,25 @@
 import 'package:webfeed/util/datetime.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class DublinCore {
-  final String title;
-  final String description;
-  final String creator;
-  final String subject;
-  final String publisher;
-  final String contributor;
-  final DateTime date;
-  final DateTime created;
-  final DateTime modified;
-  final String type;
-  final String format;
-  final String identifier;
-  final String source;
-  final String language;
-  final String relation;
-  final String coverage;
-  final String rights;
+  final String? title;
+  final String? description;
+  final String? creator;
+  final String? subject;
+  final String? publisher;
+  final String? contributor;
+  final DateTime? date;
+  final DateTime? created;
+  final DateTime? modified;
+  final String? type;
+  final String? format;
+  final String? identifier;
+  final String? source;
+  final String? language;
+  final String? relation;
+  final String? coverage;
+  final String? rights;
 
   DublinCore({
     this.title,
@@ -42,27 +42,26 @@ class DublinCore {
   });
 
   factory DublinCore.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return DublinCore(
-      title: findFirstElement(element, 'dc:title')?.text,
-      description: findFirstElement(element, 'dc:description')?.text,
-      creator: findFirstElement(element, 'dc:creator')?.text,
-      subject: findFirstElement(element, 'dc:subject')?.text,
-      publisher: findFirstElement(element, 'dc:publisher')?.text,
-      contributor: findFirstElement(element, 'dc:contributor')?.text,
-      date: parseDateTime(findFirstElement(element, 'dc:date')?.text),
-      created: parseDateTime(findFirstElement(element, 'dc:created')?.text),
-      modified: parseDateTime(findFirstElement(element, 'dc:modified')?.text),
-      type: findFirstElement(element, 'dc:type')?.text,
-      format: findFirstElement(element, 'dc:format')?.text,
-      identifier: findFirstElement(element, 'dc:identifier')?.text,
-      source: findFirstElement(element, 'dc:source')?.text,
-      language: findFirstElement(element, 'dc:language')?.text,
-      relation: findFirstElement(element, 'dc:relation')?.text,
-      coverage: findFirstElement(element, 'dc:coverage')?.text,
-      rights: findFirstElement(element, 'dc:rights')?.text,
+      title: element.findElements('dc:title').firstOrNull?.text,
+      description: element.findElements('dc:description').firstOrNull?.text,
+      creator: element.findElements('dc:creator').firstOrNull?.text,
+      subject: element.findElements('dc:subject').firstOrNull?.text,
+      publisher: element.findElements('dc:publisher').firstOrNull?.text,
+      contributor: element.findElements('dc:contributor').firstOrNull?.text,
+      date: parseDateTime(element.findElements('dc:date').firstOrNull?.text),
+      created:
+          parseDateTime(element.findElements('dc:created').firstOrNull?.text),
+      modified:
+          parseDateTime(element.findElements('dc:modified').firstOrNull?.text),
+      type: element.findElements('dc:type').firstOrNull?.text,
+      format: element.findElements('dc:format').firstOrNull?.text,
+      identifier: element.findElements('dc:identifier').firstOrNull?.text,
+      source: element.findElements('dc:source').firstOrNull?.text,
+      language: element.findElements('dc:language').firstOrNull?.text,
+      relation: element.findElements('dc:relation').firstOrNull?.text,
+      coverage: element.findElements('dc:coverage').firstOrNull?.text,
+      rights: element.findElements('dc:rights').firstOrNull?.text,
     );
   }
 }

lib/domain/itunes/itunes.dart

@@ -4,27 +4,28 @@ import 'package:webfeed/domain/itunes/itunes_image.dart';
 import 'package:webfeed/domain/itunes/itunes_owner.dart';
 import 'package:webfeed/domain/itunes/itunes_type.dart';
 import 'package:webfeed/util/string.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:webfeed/util/xml.dart';
 import 'package:xml/xml.dart';
 
 class Itunes {
-  final String author;
-  final String summary;
-  final bool explicit;
-  final String title;
-  final String subtitle;
-  final ItunesOwner owner;
-  final List<String> keywords;
-  final ItunesImage image;
-  final List<ItunesCategory> categories;
-  final ItunesType type;
-  final String newFeedUrl;
-  final bool block;
-  final bool complete;
-  final int episode;
-  final int season;
-  final Duration duration;
-  final ItunesEpisodeType episodeType;
+  final String? author;
+  final String? summary;
+  final bool? explicit;
+  final String? title;
+  final String? subtitle;
+  final ItunesOwner? owner;
+  final List<String>? keywords;
+  final ItunesImage? image;
+  final List<ItunesCategory>? categories;
+  final ItunesType? type;
+  final String? newFeedUrl;
+  final bool? block;
+  final bool? complete;
+  final int? episode;
+  final int? season;
+  final Duration? duration;
+  final ItunesEpisodeType? episodeType;
 
   Itunes({
     this.author,
@@ -47,38 +48,50 @@ class Itunes {
   });
 
   factory Itunes.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
-    var episodeStr = findFirstElement(element, 'itunes:episode')?.text;
-    var seasonStr = findFirstElement(element, 'itunes:season')?.text;
-    var durationStr = findFirstElement(element, 'itunes:duration')?.text;
+    final episodeStr = element.findElements('itunes:episode').firstOrNull?.text;
+    final seasonStr = element.findElements('itunes:season').firstOrNull?.text;
+    final durationStr =
+        element.findElements('itunes:duration').firstOrNull?.text;
     return Itunes(
-      author: findFirstElement(element, 'itunes:author')?.text,
-      summary: findFirstElement(element, 'itunes:summary')?.text,
+      author: element.findElements('itunes:author').firstOrNull?.text,
+      summary: element.findElements('itunes:summary').firstOrNull?.text,
       explicit: parseBoolLiteral(element, 'itunes:explicit'),
-      title: findFirstElement(element, 'itunes:title')?.text,
-      subtitle: findFirstElement(element, 'itunes:subtitle')?.text,
-      owner: ItunesOwner.parse(findFirstElement(element, 'itunes:owner')),
-      keywords: findFirstElement(element, 'itunes:keywords')
+      title: element.findElements('itunes:title').firstOrNull?.text,
+      subtitle: element.findElements('itunes:subtitle').firstOrNull?.text,
+      owner: element
+          .findElements('itunes:owner')
+          .map((e) => ItunesOwner.parse(e))
+          .firstOrNull,
+      keywords: element
+              .findElements('itunes:keywords')
+              .firstOrNull
               ?.text
-              ?.split(',')
-              ?.map((keyword) => keyword.trim())
-              ?.toList() ??
+              .split(',')
+              .map((keyword) => keyword.trim())
+              .toList() ??
           [],
-      image: ItunesImage.parse(findFirstElement(element, 'itunes:image')),
-      categories: findElements(element, 'itunes:category')
+      image: element
+          .findElements('itunes:image')
+          .map((e) => ItunesImage.parse(e))
+          .firstOrNull,
+      categories: element
+          .findElements('itunes:category')
           .map((e) => ItunesCategory.parse(e))
           .toList(),
-      type: newItunesType(findFirstElement(element, 'itunes:type')),
-      newFeedUrl: findFirstElement(element, 'itunes:new-feed-url')?.text,
+      type: element
+          .findElements('itunes:type')
+          .map((e) => newItunesType(e))
+          .firstOrNull,
+      newFeedUrl: element.findElements('itunes:new-feed-url').firstOrNull?.text,
       block: parseBoolLiteral(element, 'itunes:block'),
       complete: parseBoolLiteral(element, 'itunes:complete'),
-      episode: isNullOrEmpty(episodeStr) ? null : int.parse(episodeStr),
-      season: isNullOrEmpty(seasonStr) ? null : int.parse(seasonStr),
+      episode: isNullOrEmpty(episodeStr) ? null : int.tryParse(episodeStr),
+      season: isNullOrEmpty(seasonStr) ? null : int.tryParse(seasonStr),
       duration: isNullOrEmpty(durationStr) ? null : _parseDuration(durationStr),
-      episodeType:
-          newItunesEpisodeType(findFirstElement(element, 'itunes:episodeType')),
+      episodeType: element
+          .findElements('itunes:episodeType')
+          .map((e) => newItunesEpisodeType(e))
+          .firstOrNull,
     );
   }
 
@@ -88,12 +101,12 @@ class Itunes {
     var seconds = 0;
     var parts = s.split(':');
     if (parts.length > 2) {
-      hours = int.parse(parts[parts.length - 3]);
+      hours = int.tryParse(parts[parts.length - 3]) ?? 0;
     }
     if (parts.length > 1) {
-      minutes = int.parse(parts[parts.length - 2]);
+      minutes = int.tryParse(parts[parts.length - 2]) ?? 0;
     }
-    seconds = int.parse(parts[parts.length - 1]);
+    seconds = int.tryParse(parts[parts.length - 1]) ?? 0;
     return Duration(
       hours: hours,
       minutes: minutes,

lib/domain/itunes/itunes_category.dart

@@ -1,20 +1,17 @@
 import 'package:xml/xml.dart';
 
 class ItunesCategory {
-  final String category;
-  final List<String> subCategories;
+  final String? category;
+  final List<String>? subCategories;
 
   ItunesCategory({this.category, this.subCategories});
 
   factory ItunesCategory.parse(XmlElement element) {
-    if (element == null) return null;
     return ItunesCategory(
-      category: element.getAttribute('text')?.trim(),
-      subCategories: element
-              .findElements('itunes:category')
-              ?.map((e) => e.getAttribute('text')?.trim())
-              ?.toList() ??
-          [],
-    );
+        category: element.getAttribute('text')?.trim(),
+        subCategories: element
+            .findElements('itunes:category')
+            .map((e) => e.getAttribute('text')?.trim() ?? '')
+            .toList());
   }
 }

lib/domain/itunes/itunes_episode_type.dart

@@ -3,7 +3,7 @@ import 'package:xml/xml.dart';
 enum ItunesEpisodeType { full, trailer, bonus, unknown }
 
 ItunesEpisodeType newItunesEpisodeType(XmlElement element) {
-  switch (element?.text) {
+  switch (element.text) {
     case 'full':
       return ItunesEpisodeType.full;
     case 'trailer':

lib/domain/itunes/itunes_image.dart

@@ -1,12 +1,11 @@
 import 'package:xml/xml.dart';
 
 class ItunesImage {
-  final String href;
+  final String? href;
 
   ItunesImage({this.href});
 
   factory ItunesImage.parse(XmlElement element) {
-    if (element == null) return null;
     return ItunesImage(
       href: element.getAttribute('href')?.trim(),
     );

lib/domain/itunes/itunes_owner.dart

@@ -1,17 +1,16 @@
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class ItunesOwner {
-  final String name;
-  final String email;
+  final String? name;
+  final String? email;
 
   ItunesOwner({this.name, this.email});
 
   factory ItunesOwner.parse(XmlElement element) {
-    if (element == null) return null;
     return ItunesOwner(
-      name: findFirstElement(element, 'itunes:name')?.text?.trim(),
-      email: findFirstElement(element, 'itunes:email')?.text?.trim(),
+      name: element.findElements('itunes:name').firstOrNull?.text.trim(),
+      email: element.findElements('itunes:email').firstOrNull?.text.trim(),
     );
   }
 }

lib/domain/itunes/itunes_type.dart

@@ -3,7 +3,7 @@ import 'package:xml/xml.dart';
 enum ItunesType { episodic, serial, unknown }
 
 ItunesType newItunesType(XmlElement element) {
-  switch (element?.text) {
+  switch (element.text) {
     case 'episodic':
       return ItunesType.episodic;
     case 'serial':

lib/domain/media/category.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class Category {
-  final String scheme;
-  final String label;
-  final String value;
+  final String? scheme;
+  final String? label;
+  final String? value;
 
   Category({
     this.scheme,
@@ -12,9 +12,6 @@ class Category {
   });
 
   factory Category.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Category(
       scheme: element.getAttribute('scheme'),
       label: element.getAttribute('label'),

lib/domain/media/community.dart

@@ -1,13 +1,13 @@
 import 'package:webfeed/domain/media/star_rating.dart';
 import 'package:webfeed/domain/media/statistics.dart';
 import 'package:webfeed/domain/media/tags.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class Community {
-  final StarRating starRating;
-  final Statistics statistics;
-  final Tags tags;
+  final StarRating? starRating;
+  final Statistics? statistics;
+  final Tags? tags;
 
   Community({
     this.starRating,
@@ -16,19 +16,19 @@ class Community {
   });
 
   factory Community.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Community(
-      starRating: StarRating.parse(
-        findFirstElement(element, 'media:starRating'),
-      ),
-      statistics: Statistics.parse(
-        findFirstElement(element, 'media:statistics'),
-      ),
-      tags: Tags.parse(
-        findFirstElement(element, 'media:tags'),
-      ),
+      starRating: element
+          .findElements('media:starRating')
+          .map((e) => StarRating.parse(e))
+          .firstOrNull,
+      statistics: element
+          .findElements('media:statistics')
+          .map((e) => Statistics.parse(e))
+          .firstOrNull,
+      tags: element
+          .findElements('media:tags')
+          .map((e) => Tags.parse(e))
+          .firstOrNull,
     );
   }
 }

lib/domain/media/content.dart

@@ -1,20 +1,20 @@
 import 'package:xml/xml.dart';
 
 class Content {
-  final String url;
-  final String type;
-  final int fileSize;
-  final String medium;
-  final bool isDefault;
-  final String expression;
-  final int bitrate;
-  final double framerate;
-  final double samplingrate;
-  final int channels;
-  final int duration;
-  final int height;
-  final int width;
-  final String lang;
+  final String? url;
+  final String? type;
+  final int? fileSize;
+  final String? medium;
+  final bool? isDefault;
+  final String? expression;
+  final int? bitrate;
+  final double? framerate;
+  final double? samplingrate;
+  final int? channels;
+  final int? duration;
+  final int? height;
+  final int? width;
+  final String? lang;
 
   Content({
     this.url,

lib/domain/media/copyright.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Copyright {
-  final String url;
-  final String value;
+  final String? url;
+  final String? value;
 
   Copyright({
     this.url,
@@ -10,9 +10,6 @@ class Copyright {
   });
 
   factory Copyright.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Copyright(
       url: element.getAttribute('url'),
       value: element.text,

lib/domain/media/credit.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class Credit {
-  final String role;
-  final String scheme;
-  final String value;
+  final String? role;
+  final String? scheme;
+  final String? value;
 
   Credit({
     this.role,

lib/domain/media/description.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Description {
-  final String type;
-  final String value;
+  final String? type;
+  final String? value;
 
   Description({
     this.type,
@@ -10,9 +10,6 @@ class Description {
   });
 
   factory Description.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Description(
       type: element.getAttribute('type'),
       value: element.text,

lib/domain/media/embed.dart

@@ -2,10 +2,10 @@ import 'package:webfeed/domain/media/param.dart';
 import 'package:xml/xml.dart';
 
 class Embed {
-  final String url;
-  final int width;
-  final int height;
-  final List<Param> params;
+  final String? url;
+  final int? width;
+  final int? height;
+  final List<Param>? params;
 
   Embed({
     this.url,
@@ -15,16 +15,14 @@ class Embed {
   });
 
   factory Embed.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Embed(
       url: element.getAttribute('url'),
       width: int.tryParse(element.getAttribute('width') ?? '0'),
       height: int.tryParse(element.getAttribute('height') ?? '0'),
-      params: element.findElements('media:param').map((e) {
-        return Param.parse(e);
-      }).toList(),
+      params: element
+          .findElements('media:param')
+          .map((e) => Param.parse(e))
+          .toList(),
     );
   }
 }

lib/domain/media/group.dart

@@ -2,14 +2,14 @@ import 'package:webfeed/domain/media/category.dart';
 import 'package:webfeed/domain/media/content.dart';
 import 'package:webfeed/domain/media/credit.dart';
 import 'package:webfeed/domain/media/rating.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class Group {
-  final List<Content> contents;
-  final List<Credit> credits;
-  final Category category;
-  final Rating rating;
+  final List<Content>? contents;
+  final List<Credit>? credits;
+  final Category? category;
+  final Rating? rating;
 
   Group({
     this.contents,
@@ -19,22 +19,23 @@ class Group {
   });
 
   factory Group.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Group(
-      contents: element.findElements('media:content').map((e) {
-        return Content.parse(e);
-      }).toList(),
-      credits: element.findElements('media:credit').map((e) {
-        return Credit.parse(e);
-      }).toList(),
-      category: Category.parse(
-        findFirstElement(element, 'media:category'),
-      ),
-      rating: Rating.parse(
-        findFirstElement(element, 'media:rating'),
-      ),
+      contents: element
+          .findElements('media:content')
+          .map((e) => Content.parse(e))
+          .toList(),
+      credits: element
+          .findElements('media:credit')
+          .map((e) => Credit.parse(e))
+          .toList(),
+      category: element
+          .findElements('media:category')
+          .map((e) => Category.parse(e))
+          .firstOrNull,
+      rating: element
+          .findElements('media:rating')
+          .map((e) => Rating.parse(e))
+          .firstOrNull,
     );
   }
 }

lib/domain/media/hash.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Hash {
-  final String algo;
-  final String value;
+  final String? algo;
+  final String? value;
 
   Hash({
     this.algo,
@@ -10,9 +10,6 @@ class Hash {
   });
 
   factory Hash.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Hash(
       algo: element.getAttribute('algo'),
       value: element.text,

lib/domain/media/license.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class License {
-  final String type;
-  final String href;
-  final String value;
+  final String? type;
+  final String? href;
+  final String? value;
 
   License({
     this.type,
@@ -12,9 +12,6 @@ class License {
   });
 
   factory License.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return License(
       type: element.getAttribute('type'),
       href: element.getAttribute('href'),

lib/domain/media/media.dart

@@ -20,34 +20,35 @@ import 'package:webfeed/domain/media/text.dart';
 import 'package:webfeed/domain/media/thumbnail.dart';
 import 'package:webfeed/domain/media/title.dart';
 import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class Media {
-  final Group group;
-  final List<Content> contents;
-  final List<Credit> credits;
-  final Category category;
-  final Rating rating;
-  final Title title;
-  final Description description;
-  final String keywords;
-  final List<Thumbnail> thumbnails;
-  final Hash hash;
-  final Player player;
-  final Copyright copyright;
-  final Text text;
-  final Restriction restriction;
-  final Community community;
-  final List<String> comments;
-  final Embed embed;
-  final List<String> responses;
-  final List<String> backLinks;
-  final Status status;
-  final List<Price> prices;
-  final License license;
-  final PeerLink peerLink;
-  final Rights rights;
-  final List<Scene> scenes;
+  final Group? group;
+  final List<Content>? contents;
+  final List<Credit>? credits;
+  final Category? category;
+  final Rating? rating;
+  final Title? title;
+  final Description? description;
+  final String? keywords;
+  final List<Thumbnail>? thumbnails;
+  final Hash? hash;
+  final Player? player;
+  final Copyright? copyright;
+  final Text? text;
+  final Restriction? restriction;
+  final Community? community;
+  final List<String>? comments;
+  final Embed? embed;
+  final List<String>? responses;
+  final List<String>? backLinks;
+  final Status? status;
+  final List<Price>? prices;
+  final License? license;
+  final PeerLink? peerLink;
+  final Rights? rights;
+  final List<Scene>? scenes;
 
   Media({
     this.group,
@@ -79,90 +80,113 @@ class Media {
 
   factory Media.parse(XmlElement element) {
     return Media(
-      group: Group.parse(
-        findFirstElement(element, 'media:group'),
-      ),
-      contents: element.findElements('media:content').map((e) {
-        return Content.parse(e);
-      }).toList(),
-      credits: element.findElements('media:credit').map((e) {
-        return Credit.parse(e);
-      }).toList(),
-      category: Category.parse(
-        findFirstElement(element, 'media:category'),
-      ),
-      rating: Rating.parse(
-        findFirstElement(element, 'media:rating'),
-      ),
-      title: Title.parse(
-        findFirstElement(element, 'media:title'),
-      ),
-      description: Description.parse(
-        findFirstElement(element, 'media:description'),
-      ),
-      keywords: findFirstElement(element, 'media:keywords')?.text,
-      thumbnails: element.findElements('media:thumbnail').map((e) {
-        return Thumbnail.parse(e);
-      }).toList(),
-      hash: Hash.parse(
-        findFirstElement(element, 'media:hash'),
-      ),
-      player: Player.parse(
-        findFirstElement(element, 'media:player'),
-      ),
-      copyright: Copyright.parse(
-        findFirstElement(element, 'media:copyright'),
-      ),
-      text: Text.parse(
-        findFirstElement(element, 'media:text'),
-      ),
-      restriction: Restriction.parse(
-        findFirstElement(element, 'media:restriction'),
-      ),
-      community: Community.parse(
-        findFirstElement(element, 'media:community'),
-      ),
-      comments: findFirstElement(element, 'media:comments')
+      group: element
+          .findElements('media:group')
+          .map((e) => Group.parse(e))
+          .firstOrNull,
+      contents: element
+          .findElements('media:content')
+          .map((e) => Content.parse(e))
+          .toList(),
+      credits: element
+          .findElements('media:credit')
+          .map((e) => Credit.parse(e))
+          .toList(),
+      category: element
+          .findElements('media:category')
+          .map((e) => Category.parse(e))
+          .firstOrNull,
+      rating: element
+          .findElements('media:rating')
+          .map((e) => Rating.parse(e))
+          .firstOrNull,
+      title: findElements(element, 'media:title')
+          ?.map((e) => Title.parse(e))
+          .firstOrNull,
+      description: element
+          .findElements('media:description')
+          .map((e) => Description.parse(e))
+          .firstOrNull,
+      keywords: element.findElements('media:keywords').firstOrNull?.text,
+      thumbnails: element
+          .findElements('media:thumbnail')
+          .map((e) => Thumbnail.parse(e))
+          .toList(),
+      hash: element
+          .findElements('media:hash')
+          .map((e) => Hash.parse(e))
+          .firstOrNull,
+      player: element
+          .findElements('media:player')
+          .map((e) => Player.parse(e))
+          .firstOrNull,
+      copyright: element
+          .findElements('media:copyright')
+          .map((e) => Copyright.parse(e))
+          .firstOrNull,
+      text: element
+          .findElements('media:text')
+          .map((e) => Text.parse(e))
+          .firstOrNull,
+      restriction: element
+          .findElements('media:restriction')
+          .map((e) => Restriction.parse(e))
+          .firstOrNull,
+      community: element
+          .findElements('media:community')
+          .map((e) => Community.parse(e))
+          .firstOrNull,
+      comments: element
+              .findElements('media:comments')
+              .firstOrNull
               ?.findElements('media:comment')
-              ?.map((e) {
-            return e.text;
-          })?.toList() ??
+              .map((e) => e.text)
+              .toList() ??
           [],
-      embed: Embed.parse(
-        findFirstElement(element, 'media:embed'),
-      ),
-      responses: findFirstElement(element, 'media:responses')
+      embed: element
+          .findElements('media:embed')
+          .map((e) => Embed.parse(e))
+          .firstOrNull,
+      responses: element
+              .findElements('media:responses')
+              .firstOrNull
               ?.findElements('media:response')
-              ?.map((e) {
-            return e.text;
-          })?.toList() ??
+              .map((e) => e.text)
+              .toList() ??
           [],
-      backLinks: findFirstElement(element, 'media:backLinks')
+      backLinks: element
+              .findElements('media:backLinks')
+              .firstOrNull
               ?.findElements('media:backLink')
-              ?.map((e) {
-            return e.text;
-          })?.toList() ??
+              .map((e) => e.text)
+              .toList() ??
           [],
-      status: Status.parse(
-        findFirstElement(element, 'media:status'),
-      ),
-      prices: element.findElements('media:price').map((e) {
-        return Price.parse(e);
-      }).toList(),
-      license: License.parse(
-        findFirstElement(element, 'media:license'),
-      ),
-      peerLink: PeerLink.parse(
-        findFirstElement(element, 'media:peerLink'),
-      ),
-      rights: Rights.parse(
-        findFirstElement(element, 'media:rights'),
-      ),
-      scenes: findFirstElement(element, 'media:scenes')
+      status: element
+          .findElements('media:status')
+          .map((e) => Status.parse(e))
+          .firstOrNull,
+      prices: element
+          .findElements('media:price')
+          .map((e) => Price.parse(e))
+          .toList(),
+      license: element
+          .findElements('media:license')
+          .map((e) => License.parse(e))
+          .firstOrNull,
+      peerLink: element
+          .findElements('media:peerLink')
+          .map((e) => PeerLink.parse(e))
+          .firstOrNull,
+      rights: element
+          .findElements('media:rights')
+          .map((e) => Rights.parse(e))
+          .firstOrNull,
+      scenes: element
+              .findElements('media:scenes')
+              .firstOrNull
               ?.findElements('media:scene')
-              ?.map((e) {
-            return Scene.parse(e);
-          })?.toList() ??
+              .map((e) => Scene.parse(e))
+              .toList() ??
           [],
     );
   }

lib/domain/media/param.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Param {
-  final String name;
-  final String value;
+  final String? name;
+  final String? value;
 
   Param({
     this.name,
@@ -10,9 +10,6 @@ class Param {
   });
 
   factory Param.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Param(
       name: element.getAttribute('name'),
       value: element.text,

lib/domain/media/peer_link.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class PeerLink {
-  final String type;
-  final String href;
-  final String value;
+  final String? type;
+  final String? href;
+  final String? value;
 
   PeerLink({
     this.type,
@@ -12,9 +12,6 @@ class PeerLink {
   });
 
   factory PeerLink.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return PeerLink(
       type: element.getAttribute('type'),
       href: element.getAttribute('href'),

lib/domain/media/player.dart

@@ -1,10 +1,10 @@
 import 'package:xml/xml.dart';
 
 class Player {
-  final String url;
-  final int width;
-  final int height;
-  final String value;
+  final String? url;
+  final int? width;
+  final int? height;
+  final String? value;
 
   Player({
     this.url,
@@ -14,9 +14,6 @@ class Player {
   });
 
   factory Player.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Player(
       url: element.getAttribute('url'),
       width: int.tryParse(element.getAttribute('width') ?? '0'),

lib/domain/media/price.dart

@@ -1,10 +1,10 @@
 import 'package:xml/xml.dart';
 
 class Price {
-  final double price;
-  final String type;
-  final String info;
-  final String currency;
+  final double? price;
+  final String? type;
+  final String? info;
+  final String? currency;
 
   Price({
     this.price,

lib/domain/media/rating.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Rating {
-  final String scheme;
-  final String value;
+  final String? scheme;
+  final String? value;
 
   Rating({
     this.scheme,
@@ -10,9 +10,6 @@ class Rating {
   });
 
   factory Rating.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Rating(
       scheme: element.getAttribute('scheme'),
       value: element.text,

lib/domain/media/restriction.dart

@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class Restriction {
-  final String relationship;
-  final String type;
-  final String value;
+  final String? relationship;
+  final String? type;
+  final String? value;
 
   Restriction({
     this.relationship,
@@ -12,9 +12,6 @@ class Restriction {
   });
 
   factory Restriction.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Restriction(
       relationship: element.getAttribute('relationship'),
       type: element.getAttribute('type'),

lib/domain/media/rights.dart

@@ -1,16 +1,13 @@
 import 'package:xml/xml.dart';
 
 class Rights {
-  final String status;
+  final String? status;
 
   Rights({
     this.status,
   });
 
   factory Rights.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Rights(
       status: element.getAttribute('status'),
     );

lib/domain/media/scene.dart

@@ -1,11 +1,11 @@
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class Scene {
-  final String title;
-  final String description;
-  final String startTime;
-  final String endTime;
+  final String? title;
+  final String? description;
+  final String? startTime;
+  final String? endTime;
 
   Scene({
     this.title,
@@ -15,14 +15,11 @@ class Scene {
   });
 
   factory Scene.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Scene(
-      title: findFirstElement(element, 'sceneTitle')?.text,
-      description: findFirstElement(element, 'sceneDescription')?.text,
-      startTime: findFirstElement(element, 'sceneStartTime')?.text,
-      endTime: findFirstElement(element, 'sceneEndTime')?.text,
+      title: element.findElements('sceneTitle').firstOrNull?.text,
+      description: element.findElements('sceneDescription').firstOrNull?.text,
+      startTime: element.findElements('sceneStartTime').firstOrNull?.text,
+      endTime: element.findElements('sceneEndTime').firstOrNull?.text,
     );
   }
 }

lib/domain/media/star_rating.dart

@@ -1,10 +1,10 @@
 import 'package:xml/xml.dart';
 
 class StarRating {
-  final double average;
-  final int count;
-  final int min;
-  final int max;
+  final double? average;
+  final int? count;
+  final int? min;
+  final int? max;
 
   StarRating({
     this.average,
@@ -13,12 +13,12 @@ class StarRating {
     this.max,
   });
 
-  factory StarRating.parse(XmlElement element) {
+  factory StarRating.parse(XmlElement? element) {
     return StarRating(
-      average: double.tryParse(element.getAttribute('average') ?? '0'),
-      count: int.tryParse(element.getAttribute('count') ?? '0'),
-      min: int.tryParse(element.getAttribute('min') ?? '0'),
-      max: int.tryParse(element.getAttribute('max') ?? '0'),
+      average: double.tryParse(element?.getAttribute('average') ?? '0'),
+      count: int.tryParse(element?.getAttribute('count') ?? '0'),
+      min: int.tryParse(element?.getAttribute('min') ?? '0'),
+      max: int.tryParse(element?.getAttribute('max') ?? '0'),
     );
   }
 }

lib/domain/media/statistics.dart

@@ -1,18 +1,18 @@
 import 'package:xml/xml.dart';
 
 class Statistics {
-  final int views;
-  final int favorites;
+  final int? views;
+  final int? favorites;
 
   Statistics({
     this.views,
     this.favorites,
   });
 
-  factory Statistics.parse(XmlElement element) {
+  factory Statistics.parse(XmlElement? element) {
     return Statistics(
-      views: int.tryParse(element.getAttribute('views') ?? '0'),
-      favorites: int.tryParse(element.getAttribute('favorites') ?? '0'),
+      views: int.tryParse(element?.getAttribute('views') ?? '0'),
+      favorites: int.tryParse(element?.getAttribute('favorites') ?? '0'),
     );
   }
 }

lib/domain/media/status.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Status {
-  final String state;
-  final String reason;
+  final String? state;
+  final String? reason;
 
   Status({
     this.state,
@@ -10,9 +10,6 @@ class Status {
   });
 
   factory Status.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Status(
       state: element.getAttribute('state'),
       reason: element.getAttribute('reason'),

lib/domain/media/tags.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Tags {
-  final String tags;
-  final int weight;
+  final String? tags;
+  final int? weight;
 
   Tags({
     this.tags,
@@ -10,9 +10,6 @@ class Tags {
   });
 
   factory Tags.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Tags(
       tags: element.text,
       weight: int.tryParse(element.getAttribute('weight') ?? '1'),

lib/domain/media/text.dart

@@ -1,11 +1,11 @@
 import 'package:xml/xml.dart';
 
 class Text {
-  final String type;
-  final String lang;
-  final String start;
-  final String end;
-  final String value;
+  final String? type;
+  final String? lang;
+  final String? start;
+  final String? end;
+  final String? value;
 
   Text({
     this.type,
@@ -16,9 +16,6 @@ class Text {
   });
 
   factory Text.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Text(
       type: element.getAttribute('type'),
       lang: element.getAttribute('lang'),

lib/domain/media/thumbnail.dart

@@ -1,10 +1,10 @@
 import 'package:xml/xml.dart';
 
 class Thumbnail {
-  final String url;
-  final String width;
-  final String height;
-  final String time;
+  final String? url;
+  final String? width;
+  final String? height;
+  final String? time;
 
   Thumbnail({
     this.url,

lib/domain/media/title.dart

@@ -1,8 +1,8 @@
 import 'package:xml/xml.dart';
 
 class Title {
-  final String type;
-  final String value;
+  final String? type;
+  final String? value;
 
   Title({
     this.type,
@@ -10,9 +10,6 @@ class Title {
   });
 
   factory Title.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return Title(
       type: element.getAttribute('type'),
       value: element.text,

lib/domain/rss_category.dart

@@ -1,15 +1,12 @@
 import 'package:xml/xml.dart';
 
 class RssCategory {
-  final String domain;
+  final String? domain;
   final String value;
 
   RssCategory(this.domain, this.value);
 
   factory RssCategory.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     var domain = element.getAttribute('domain');
     var value = element.text;
 

lib/domain/rss_cloud.dart

@@ -1,11 +1,11 @@
 import 'package:xml/xml.dart';
 
 class RssCloud {
-  final String domain;
-  final String port;
-  final String path;
-  final String registerProcedure;
-  final String protocol;
+  final String? domain;
+  final String? port;
+  final String? path;
+  final String? registerProcedure;
+  final String? protocol;
 
   RssCloud(
     this.domain,
@@ -16,9 +16,6 @@ class RssCloud {
   );
 
   factory RssCloud.parse(XmlElement node) {
-    if (node == null) {
-      return null;
-    }
     var domain = node.getAttribute('domain');
     var port = node.getAttribute('port');
     var path = node.getAttribute('path');

lib/domain/rss_content.dart

@@ -17,13 +17,10 @@ class RssContent {
   RssContent(this.value, this.images);
 
   factory RssContent.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
-    final content = element.text;
+    final dynamic? content = element.text;
     final images = <String>[];
     _imagesRegExp.allMatches(content).forEach((match) {
-      images.add(match.group(1));
+      images.add(match.group(1)!);
     });
     return RssContent(content, images);
   }

lib/domain/rss_enclosure.dart

@@ -1,16 +1,13 @@
 import 'package:xml/xml.dart';
 
 class RssEnclosure {
-  final String url;
-  final String type;
-  final int length;
+  final String? url;
+  final String? type;
+  final int? length;
 
   RssEnclosure(this.url, this.type, this.length);
 
   factory RssEnclosure.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     var url = element.getAttribute('url');
     var type = element.getAttribute('type');
     var length = int.tryParse(element.getAttribute('length') ?? '0');

lib/domain/rss_feed.dart

@@ -7,33 +7,33 @@ import 'package:webfeed/domain/rss_cloud.dart';
 import 'package:webfeed/domain/rss_image.dart';
 import 'package:webfeed/domain/rss_item.dart';
 import 'package:webfeed/domain/syndication/syndication.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class RssFeed {
-  final String title;
-  final String author;
-  final String description;
-  final String link;
-  final List<RssItem> items;
+  final String? title;
+  final String? author;
+  final String? description;
+  final String? link;
+  final List<RssItem>? items;
 
-  final RssImage image;
-  final RssCloud cloud;
-  final List<RssCategory> categories;
-  final List<String> skipDays;
-  final List<int> skipHours;
-  final String lastBuildDate;
-  final String language;
-  final String generator;
-  final String copyright;
-  final String docs;
-  final String managingEditor;
-  final String rating;
-  final String webMaster;
-  final int ttl;
-  final DublinCore dc;
-  final Itunes itunes;
-  final Syndication syndication;
+  final RssImage? image;
+  final RssCloud? cloud;
+  final List<RssCategory>? categories;
+  final List<String>? skipDays;
+  final List<int>? skipHours;
+  final String? lastBuildDate;
+  final String? language;
+  final String? generator;
+  final String? copyright;
+  final String? docs;
+  final String? managingEditor;
+  final String? rating;
+  final String? webMaster;
+  final int? ttl;
+  final DublinCore? dc;
+  final Itunes? itunes;
+  final Syndication? syndication;
 
   RssFeed({
     this.title,
@@ -62,50 +62,62 @@ class RssFeed {
 
   factory RssFeed.parse(String xmlString) {
     var document = XmlDocument.parse(xmlString);
-    var rss = findFirstElement(document, 'rss');
-    var rdf = findFirstElement(document, 'rdf:RDF');
+    var rss = document.findElements('rss').firstOrNull;
+    var rdf = document.findElements('rdf:RDF').firstOrNull;
     if (rss == null && rdf == null) {
       throw ArgumentError('not a rss feed');
     }
-    var channelElement = findFirstElement(rss ?? rdf, 'channel');
+    var channelElement = (rss ?? rdf)!.findElements('channel').firstOrNull;
     if (channelElement == null) {
       throw ArgumentError('channel not found');
     }
     return RssFeed(
-      title: findFirstElement(channelElement, 'title')?.text,
-      author: findFirstElement(channelElement, 'author')?.text,
-      description: findFirstElement(channelElement, 'description')?.text,
-      link: findFirstElement(channelElement, 'link')?.text,
-      items: (rss != null ? channelElement : rdf)
+      title: channelElement.findElements('title').firstOrNull?.text,
+      author: channelElement.findElements('author').firstOrNull?.text,
+      description: channelElement.findElements('description').firstOrNull?.text,
+      link: channelElement.findElements('link').firstOrNull?.text,
+      items: (rdf ?? channelElement)
           .findElements('item')
           .map((e) => RssItem.parse(e))
           .toList(),
-      image: RssImage.parse(
-          findFirstElement(rss != null ? channelElement : rdf, 'image')),
-      cloud: RssCloud.parse(findFirstElement(channelElement, 'cloud')),
+      image: (rdf ?? channelElement)
+          .findElements('image')
+          .map((e) => RssImage.parse(e))
+          .firstOrNull,
+      cloud: channelElement
+          .findElements('cloud')
+          .map((e) => RssCloud.parse(e))
+          .firstOrNull,
       categories: channelElement
           .findElements('category')
           .map((e) => RssCategory.parse(e))
           .toList(),
-      skipDays: findFirstElement(channelElement, 'skipDays')
+      skipDays: channelElement
+              .findElements('skipDays')
+              .firstOrNull
               ?.findAllElements('day')
-              ?.map((e) => e.text)
-              ?.toList() ??
+              .map((e) => e.text)
+              .toList() ??
           [],
-      skipHours: findFirstElement(channelElement, 'skipHours')
+      skipHours: channelElement
+              .findElements('skipHours')
+              .firstOrNull
               ?.findAllElements('hour')
-              ?.map((e) => int.tryParse(e.text ?? '0'))
-              ?.toList() ??
+              .map((e) => int.tryParse(e.text) ?? 0)
+              .toList() ??
           [],
-      lastBuildDate: findFirstElement(channelElement, 'lastBuildDate')?.text,
-      language: findFirstElement(channelElement, 'language')?.text,
-      generator: findFirstElement(channelElement, 'generator')?.text,
-      copyright: findFirstElement(channelElement, 'copyright')?.text,
-      docs: findFirstElement(channelElement, 'docs')?.text,
-      managingEditor: findFirstElement(channelElement, 'managingEditor')?.text,
-      rating: findFirstElement(channelElement, 'rating')?.text,
-      webMaster: findFirstElement(channelElement, 'webMaster')?.text,
-      ttl: int.tryParse(findFirstElement(channelElement, 'ttl')?.text ?? '0'),
+      lastBuildDate:
+          channelElement.findElements('lastBuildDate').firstOrNull?.text,
+      language: channelElement.findElements('language').firstOrNull?.text,
+      generator: channelElement.findElements('generator').firstOrNull?.text,
+      copyright: channelElement.findElements('copyright').firstOrNull?.text,
+      docs: channelElement.findElements('docs').firstOrNull?.text,
+      managingEditor:
+          channelElement.findElements('managingEditor').firstOrNull?.text,
+      rating: channelElement.findElements('rating').firstOrNull?.text,
+      webMaster: channelElement.findElements('webMaster').firstOrNull?.text,
+      ttl: int.tryParse(
+          channelElement.findElements('ttl').firstOrNull?.text ?? '0'),
       dc: DublinCore.parse(channelElement),
       itunes: Itunes.parse(channelElement),
       syndication: Syndication.parse(channelElement),

lib/domain/rss_image.dart

@@ -1,21 +1,18 @@
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class RssImage {
-  final String title;
-  final String url;
-  final String link;
+  final String? title;
+  final String? url;
+  final String? link;
 
   RssImage({this.title, this.url, this.link});
 
   factory RssImage.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     return RssImage(
-      title: findFirstElement(element, 'title')?.text,
-      url: findFirstElement(element, 'url')?.text,
-      link: findFirstElement(element, 'link')?.text,
+      title: element.findElements('title').firstOrNull?.text,
+      url: element.findElements('url').firstOrNull?.text,
+      link: element.findElements('link').firstOrNull?.text,
     );
   }
 }

lib/domain/rss_item.dart

@@ -6,25 +6,25 @@ import 'package:webfeed/domain/rss_content.dart';
 import 'package:webfeed/domain/rss_enclosure.dart';
 import 'package:webfeed/domain/rss_source.dart';
 import 'package:webfeed/util/datetime.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 class RssItem {
-  final String title;
-  final String description;
-  final String link;
+  final String? title;
+  final String? description;
+  final String? link;
 
-  final List<RssCategory> categories;
-  final String guid;
-  final DateTime pubDate;
-  final String author;
-  final String comments;
-  final RssSource source;
-  final RssContent content;
-  final Media media;
-  final RssEnclosure enclosure;
-  final DublinCore dc;
-  final Itunes itunes;
+  final List<RssCategory>? categories;
+  final String? guid;
+  final DateTime? pubDate;
+  final String? author;
+  final String? comments;
+  final RssSource? source;
+  final RssContent? content;
+  final Media? media;
+  final RssEnclosure? enclosure;
+  final DublinCore? dc;
+  final Itunes? itunes;
 
   RssItem({
     this.title,
@@ -45,21 +45,30 @@ class RssItem {
 
   factory RssItem.parse(XmlElement element) {
     return RssItem(
-      title: findFirstElement(element, 'title')?.text,
-      description: findFirstElement(element, 'description')?.text,
-      link: findFirstElement(element, 'link')?.text,
+      title: element.findElements('title').firstOrNull?.text,
+      description: element.findElements('description').firstOrNull?.text,
+      link: element.findElements('link').firstOrNull?.text,
       categories: element
           .findElements('category')
           .map((e) => RssCategory.parse(e))
           .toList(),
-      guid: findFirstElement(element, 'guid')?.text,
-      pubDate: parseDateTime(findFirstElement(element, 'pubDate')?.text),
-      author: findFirstElement(element, 'author')?.text,
-      comments: findFirstElement(element, 'comments')?.text,
-      source: RssSource.parse(findFirstElement(element, 'source')),
-      content: RssContent.parse(findFirstElement(element, 'content:encoded')),
+      guid: element.findElements('guid').firstOrNull?.text,
+      pubDate: parseDateTime(element.findElements('pubDate').firstOrNull?.text),
+      author: element.findElements('author').firstOrNull?.text,
+      comments: element.findElements('comments').firstOrNull?.text,
+      source: element
+          .findElements('source')
+          .map((e) => RssSource.parse(e))
+          .firstOrNull,
+      content: element
+          .findElements('content:encoded')
+          .map((e) => RssContent.parse(e))
+          .firstOrNull,
       media: Media.parse(element),
-      enclosure: RssEnclosure.parse(findFirstElement(element, 'enclosure')),
+      enclosure: element
+          .findElements('enclosure')
+          .map((e) => RssEnclosure.parse(e))
+          .firstOrNull,
       dc: DublinCore.parse(element),
       itunes: Itunes.parse(element),
     );

lib/domain/rss_source.dart

@@ -1,15 +1,12 @@
 import 'package:xml/xml.dart';
 
 class RssSource {
-  final String url;
-  final String value;
+  final String? url;
+  final String? value;
 
   RssSource(this.url, this.value);
 
   factory RssSource.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     var url = element.getAttribute('url');
     var value = element.text;
 

lib/domain/syndication/syndication.dart

@@ -1,13 +1,13 @@
 import 'package:webfeed/util/datetime.dart';
-import 'package:webfeed/util/xml.dart';
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
 enum SyndicationUpdatePeriod { hourly, daily, weekly, monthly, yearly }
 
 class Syndication {
-  final SyndicationUpdatePeriod updatePeriod;
-  final int updateFrequency;
-  final DateTime updateBase;
+  final SyndicationUpdatePeriod? updatePeriod;
+  final int? updateFrequency;
+  final DateTime? updateBase;
 
   Syndication({
     this.updatePeriod,
@@ -16,11 +16,8 @@ class Syndication {
   });
 
   factory Syndication.parse(XmlElement element) {
-    if (element == null) {
-      return null;
-    }
     SyndicationUpdatePeriod updatePeriod;
-    switch (findFirstElement(element, 'sy:updatePeriod')?.text) {
+    switch (element.findElements('sy:updatePeriod').firstOrNull?.text) {
       case 'hourly':
         updatePeriod = SyndicationUpdatePeriod.hourly;
         break;
@@ -43,9 +40,9 @@ class Syndication {
     return Syndication(
       updatePeriod: updatePeriod,
       updateFrequency: int.tryParse(
-          findFirstElement(element, 'sy:updateFrequency')?.text ?? '1'),
-      updateBase:
-          parseDateTime(findFirstElement(element, 'sy:updateBase')?.text),
+          element.findElements('sy:updateFrequency').firstOrNull?.text ?? '1'),
+      updateBase: parseDateTime(
+          element.findElements('sy:updateBase').firstOrNull?.text),
     );
   }
 }

lib/util/datetime.dart

@@ -2,15 +2,15 @@ import 'package:intl/intl.dart';
 
 const rfc822DatePattern = 'EEE, dd MMM yyyy HH:mm:ss Z';
 
-DateTime parseDateTime(dateString) {
+DateTime? parseDateTime(dateString) {
   if (dateString == null) return null;
   return _parseRfc822DateTime(dateString) ?? _parseIso8601DateTime(dateString);
 }
 
-DateTime _parseRfc822DateTime(String dateString) {
+DateTime? _parseRfc822DateTime(String dateString) {
   try {
-    final length = dateString?.length?.clamp(0, rfc822DatePattern.length);
-    final trimmedPattern = rfc822DatePattern.substring(0, length); //Some feeds use a shortened RFC 822 date, e.g. 'Tue, 04 Aug 2020'
+    final num? length = dateString.length.clamp(0, rfc822DatePattern.length);
+    final trimmedPattern = rfc822DatePattern.substring(0, length as int?); //Some feeds use a shortened RFC 822 date, e.g. 'Tue, 04 Aug 2020'
     final format = DateFormat(trimmedPattern, 'en_US');
     return format.parse(dateString);
   } on FormatException {
@@ -18,7 +18,7 @@ DateTime _parseRfc822DateTime(String dateString) {
   }
 }
 
-DateTime _parseIso8601DateTime(dateString) {
+DateTime? _parseIso8601DateTime(dateString) {
   try {
     return DateTime.parse(dateString);
   } on FormatException {

lib/util/iterable.dart

@@ -0,0 +1,3 @@
+extension WebFeedIterable<T> on Iterable<T> {
+  T? get firstOrNull => isEmpty ? null : first;
+}

lib/util/xml.dart

@@ -1,32 +1,19 @@
 import 'dart:core';
 
+import 'package:webfeed/util/iterable.dart';
 import 'package:xml/xml.dart';
 
-XmlElement findFirstElement(
-  XmlNode node,
+Iterable<XmlElement>? findElements(
+  XmlNode? node,
   String name, {
   bool recursive = false,
-  String namespace,
-}) {
-  try {
-    return findElements(node, name, recursive: recursive, namespace: namespace)
-        ?.first;
-  } on StateError {
-    return null;
-  }
-}
-
-Iterable<XmlElement> findElements(
-  XmlNode node,
-  String name, {
-  bool recursive = false,
-  String namespace,
+  String? namespace,
 }) {
   try {
     if (recursive) {
-      return node.findAllElements(name, namespace: namespace);
+      return node?.findAllElements(name, namespace: namespace);
     } else {
-      return node.findElements(name, namespace: namespace);
+      return node?.findElements(name, namespace: namespace);
     }
   } on StateError {
     return null;
@@ -34,7 +21,7 @@ Iterable<XmlElement> findElements(
 }
 
 bool parseBoolLiteral(XmlElement element, String tagName) {
-  var v = findFirstElement(element, tagName)?.text?.toLowerCase()?.trim();
+  var v = element.findElements(tagName).firstOrNull?.text.toLowerCase().trim();
   if (v == null) return false;
   return ['yes', 'true'].contains(v);
 }

pubspec.yaml

@@ -3,10 +3,10 @@ version: 0.6.0
 description: webfeed is a dart package for parsing RSS and Atom feeds. Media, DublinCore, iTunes, Syndication namespaces are also supported.
 homepage: https://github.com/witochandra/webfeed
 environment:
-  sdk: ">=2.0.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 dependencies:
-  xml: "^4.2.0"
-  intl: "^0.16.0"
+  xml: "^5.0.2"
+  intl: "^0.17.0"
 dev_dependencies:
   test: ^1.3.0
-  http: "^0.11.3+16"
+  http: "^0.13.0"

test/atom_test.dart

@@ -23,65 +23,65 @@ void main() {
     expect(feed.title, 'Foo bar news');
     expect(feed.updated, DateTime.utc(2018, 4, 6, 13, 2, 46));
 
-    expect(feed.links.length, 2);
-    expect(feed.links.first.rel, 'foo');
-    expect(feed.links.first.type, 'text/html');
-    expect(feed.links.first.hreflang, 'en');
-    expect(feed.links.first.href, 'http://foo.bar.news/');
-    expect(feed.links.first.title, 'Foo bar news html');
-    expect(feed.links.first.length, 1000);
-
-    expect(feed.authors.length, 2);
-    expect(feed.authors.first.name, 'Alice');
-    expect(feed.authors.first.uri, 'http://foo.bar.news/people/alice');
-    expect(feed.authors.first.email, 'alice@foo.bar.news');
-
-    expect(feed.contributors.length, 2);
-    expect(feed.contributors.first.name, 'Charlie');
-    expect(feed.contributors.first.uri, 'http://foo.bar.news/people/charlie');
-    expect(feed.contributors.first.email, 'charlie@foo.bar.news');
-
-    expect(feed.categories.length, 2);
-    expect(feed.categories.first.term, 'foo category');
-    expect(feed.categories.first.scheme, 'this-is-foo-scheme');
-    expect(feed.categories.first.label, 'this is foo label');
-
-    expect(feed.generator.uri, 'http://foo.bar.news/generator');
-    expect(feed.generator.version, '1.0');
-    expect(feed.generator.value, 'Foo bar generator');
+    expect(feed.links!.length, 2);
+    expect(feed.links!.first.rel, 'foo');
+    expect(feed.links!.first.type, 'text/html');
+    expect(feed.links!.first.hreflang, 'en');
+    expect(feed.links!.first.href, 'http://foo.bar.news/');
+    expect(feed.links!.first.title, 'Foo bar news html');
+    expect(feed.links!.first.length, 1000);
+
+    expect(feed.authors!.length, 2);
+    expect(feed.authors!.first.name, 'Alice');
+    expect(feed.authors!.first.uri, 'http://foo.bar.news/people/alice');
+    expect(feed.authors!.first.email, 'alice@foo.bar.news');
+
+    expect(feed.contributors!.length, 2);
+    expect(feed.contributors!.first.name, 'Charlie');
+    expect(feed.contributors!.first.uri, 'http://foo.bar.news/people/charlie');
+    expect(feed.contributors!.first.email, 'charlie@foo.bar.news');
+
+    expect(feed.categories!.length, 2);
+    expect(feed.categories!.first.term, 'foo category');
+    expect(feed.categories!.first.scheme, 'this-is-foo-scheme');
+    expect(feed.categories!.first.label, 'this is foo label');
+
+    expect(feed.generator!.uri, 'http://foo.bar.news/generator');
+    expect(feed.generator!.version, '1.0');
+    expect(feed.generator!.value, 'Foo bar generator');
 
     expect(feed.icon, 'http://foo.bar.news/icon.png');
     expect(feed.logo, 'http://foo.bar.news/logo.png');
     expect(feed.subtitle, 'This is subtitle');
 
-    expect(feed.items.length, 2);
-    var item = feed.items.first;
+    expect(feed.items!.length, 2);
+    var item = feed.items!.first;
     expect(item.id, 'foo-bar-entry-id-1');
     expect(item.title, 'Foo bar item 1');
     expect(item.updated, DateTime.utc(2018, 4, 6, 13, 2, 40));
 
-    expect(item.authors.length, 2);
-    expect(item.authors.first.name, 'Ellie');
-    expect(item.authors.first.uri, 'http://foo.bar.news/people/ellie');
-    expect(item.authors.first.email, 'ellie@foo.bar.news');
-
-    expect(item.links.length, 2);
-    expect(item.links.first.rel, 'foo entry');
-    expect(item.links.first.type, 'text/html');
-    expect(item.links.first.hreflang, 'en');
-    expect(item.links.first.href, 'http://foo.bar.news/entry');
-    expect(item.links.first.title, 'Foo bar news html');
-    expect(item.links.first.length, 1000);
-
-    expect(item.categories.length, 2);
-    expect(item.categories.first.term, 'foo entry category');
-    expect(item.categories.first.scheme, 'this-is-foo-entry-scheme');
-    expect(item.categories.first.label, 'this is foo entry label');
-
-    expect(item.contributors.length, 2);
-    expect(item.contributors.first.name, 'Gin');
-    expect(item.contributors.first.uri, 'http://foo.bar.news/people/gin');
-    expect(item.contributors.first.email, 'gin@foo.bar.news');
+    expect(item.authors!.length, 2);
+    expect(item.authors!.first.name, 'Ellie');
+    expect(item.authors!.first.uri, 'http://foo.bar.news/people/ellie');
+    expect(item.authors!.first.email, 'ellie@foo.bar.news');
+
+    expect(item.links!.length, 2);
+    expect(item.links!.first.rel, 'foo entry');
+    expect(item.links!.first.type, 'text/html');
+    expect(item.links!.first.hreflang, 'en');
+    expect(item.links!.first.href, 'http://foo.bar.news/entry');
+    expect(item.links!.first.title, 'Foo bar news html');
+    expect(item.links!.first.length, 1000);
+
+    expect(item.categories!.length, 2);
+    expect(item.categories!.first.term, 'foo entry category');
+    expect(item.categories!.first.scheme, 'this-is-foo-entry-scheme');
+    expect(item.categories!.first.label, 'this is foo entry label');
+
+    expect(item.contributors!.length, 2);
+    expect(item.contributors!.first.name, 'Gin');
+    expect(item.contributors!.first.uri, 'http://foo.bar.news/people/gin');
+    expect(item.contributors!.first.email, 'gin@foo.bar.news');
 
     expect(item.published, '2018-04-06T13:02:49Z');
     expect(item.summary, 'This is summary 1');
@@ -96,16 +96,16 @@ void main() {
     expect(feed.title, 'Foo bar news');
     expect(feed.updated, DateTime.utc(2018, 4, 6, 13, 2, 46));
 
-    expect(feed.items.length, 1);
+    expect(feed.items!.length, 1);
 
-    var item = feed.items.first;
-    expect(item.media.group.contents.length, 5);
-    expect(item.media.group.credits.length, 2);
-    expect(item.media.group.category.value, 'music/artist name/album/song');
-    expect(item.media.group.rating.value, 'nonadult');
+    var item = feed.items!.first;
+    expect(item.media!.group!.contents!.length, 5);
+    expect(item.media!.group!.credits!.length, 2);
+    expect(item.media!.group!.category!.value, 'music/artist name/album/song');
+    expect(item.media!.group!.rating!.value, 'nonadult');
 
-    expect(item.media.contents.length, 2);
-    var mediaContent = item.media.contents.first;
+    expect(item.media!.contents!.length, 2);
+    var mediaContent = item.media!.contents!.first;
     expect(mediaContent.url, 'http://www.foo.com/video.mov');
     expect(mediaContent.type, 'video/quicktime');
     expect(mediaContent.fileSize, 2000);
@@ -117,111 +117,111 @@ void main() {
     expect(mediaContent.samplingrate, 44.1);
     expect(mediaContent.channels, 2);
 
-    expect(item.media.credits.length, 2);
-    var mediaCredit = item.media.credits.first;
+    expect(item.media!.credits!.length, 2);
+    var mediaCredit = item.media!.credits!.first;
     expect(mediaCredit.role, 'owner1');
     expect(mediaCredit.scheme, 'urn:yvs');
     expect(mediaCredit.value, 'copyright holder of the entity');
 
-    expect(item.media.category.scheme,
+    expect(item.media!.category!.scheme,
         'http://search.yahoo.com/mrss/category_ schema');
-    expect(item.media.category.label, 'Music');
-    expect(item.media.category.value, 'music/artist/album/song');
+    expect(item.media!.category!.label, 'Music');
+    expect(item.media!.category!.value, 'music/artist/album/song');
 
-    expect(item.media.rating.scheme, 'urn:simple');
-    expect(item.media.rating.value, 'adult');
+    expect(item.media!.rating!.scheme, 'urn:simple');
+    expect(item.media!.rating!.value, 'adult');
 
-    expect(item.media.title.type, 'plain');
-    expect(item.media.title.value, "The Judy's -- The Moo Song");
+    expect(item.media!.title!.type, 'plain');
+    expect(item.media!.title!.value, "The Judy's -- The Moo Song");
 
-    expect(item.media.description.type, 'plain');
-    expect(item.media.description.value,
+    expect(item.media!.description!.type, 'plain');
+    expect(item.media!.description!.value,
         'This was some really bizarre band I listened to as a young lad.');
 
-    expect(item.media.keywords, 'kitty, cat, big dog, yarn, fluffy');
+    expect(item.media!.keywords, 'kitty, cat, big dog, yarn, fluffy');
 
-    expect(item.media.thumbnails.length, 2);
-    var mediaThumbnail = item.media.thumbnails.first;
+    expect(item.media!.thumbnails!.length, 2);
+    var mediaThumbnail = item.media!.thumbnails!.first;
     expect(mediaThumbnail.url, 'http://www.foo.com/keyframe1.jpg');
     expect(mediaThumbnail.width, '75');
     expect(mediaThumbnail.height, '50');
     expect(mediaThumbnail.time, '12:05:01.123');
 
-    expect(item.media.hash.algo, 'md5');
-    expect(item.media.hash.value, 'dfdec888b72151965a34b4b59031290a');
-
-    expect(item.media.player.url, 'http://www.foo.com/player?id=1111');
-    expect(item.media.player.width, 400);
-    expect(item.media.player.height, 200);
-    expect(item.media.player.value, '');
-
-    expect(item.media.copyright.url, 'http://blah.com/additional-info.html');
-    expect(item.media.copyright.value, '2005 FooBar Media');
-
-    expect(item.media.text.type, 'plain');
-    expect(item.media.text.lang, 'en');
-    expect(item.media.text.start, '00:00:03.000');
-    expect(item.media.text.end, '00:00:10.000');
-    expect(item.media.text.value, ' Oh, say, can you see');
-
-    expect(item.media.restriction.relationship, 'allow');
-    expect(item.media.restriction.type, 'country');
-    expect(item.media.restriction.value, 'au us');
-
-    expect(item.media.community.starRating.average, 3.5);
-    expect(item.media.community.starRating.count, 20);
-    expect(item.media.community.starRating.min, 1);
-    expect(item.media.community.starRating.max, 10);
-    expect(item.media.community.statistics.views, 5);
-    expect(item.media.community.statistics.favorites, 4);
-    expect(item.media.community.tags.tags, 'news: 5, abc:3');
-    expect(item.media.community.tags.weight, 1);
-
-    expect(item.media.comments.length, 2);
-    expect(item.media.comments.first, 'comment1');
-    expect(item.media.comments.last, 'comment2');
-
-    expect(item.media.embed.url, 'http://www.foo.com/player.swf');
-    expect(item.media.embed.width, 512);
-    expect(item.media.embed.height, 323);
-    expect(item.media.embed.params.length, 5);
-    expect(item.media.embed.params.first.name, 'type');
-    expect(
-        item.media.embed.params.first.value, 'application/x-shockwave-flash');
-
-    expect(item.media.responses.length, 2);
-    expect(item.media.responses.first, 'http://www.response1.com');
-    expect(item.media.responses.last, 'http://www.response2.com');
-
-    expect(item.media.backLinks.length, 2);
-    expect(item.media.backLinks.first, 'http://www.backlink1.com');
-    expect(item.media.backLinks.last, 'http://www.backlink2.com');
-
-    expect(item.media.status.state, 'active');
-    expect(item.media.status.reason, null);
-
-    expect(item.media.prices.length, 2);
-    expect(item.media.prices.first.price, 19.99);
-    expect(item.media.prices.first.type, 'rent');
-    expect(
-        item.media.prices.first.info, 'http://www.dummy.jp/package_info.html');
-    expect(item.media.prices.first.currency, 'EUR');
-
-    expect(item.media.license.type, 'text/html');
-    expect(item.media.license.href, 'http://www.licensehost.com/license');
-    expect(item.media.license.value, ' Sample license for a video');
-
-    expect(item.media.peerLink.type, 'application/x-bittorrent');
-    expect(item.media.peerLink.href, 'http://www.foo.org/sampleFile.torrent');
-    expect(item.media.peerLink.value, '');
-
-    expect(item.media.rights.status, 'official');
-
-    expect(item.media.scenes.length, 2);
-    expect(item.media.scenes.first.title, 'sceneTitle1');
-    expect(item.media.scenes.first.description, 'sceneDesc1');
-    expect(item.media.scenes.first.startTime, '00:15');
-    expect(item.media.scenes.first.endTime, '00:45');
+    expect(item.media!.hash!.algo, 'md5');
+    expect(item.media!.hash!.value, 'dfdec888b72151965a34b4b59031290a');
+
+    expect(item.media!.player!.url, 'http://www.foo.com/player?id=1111');
+    expect(item.media!.player!.width, 400);
+    expect(item.media!.player!.height, 200);
+    expect(item.media!.player!.value, '');
+
+    expect(item.media!.copyright!.url, 'http://blah.com/additional-info.html');
+    expect(item.media!.copyright!.value, '2005 FooBar Media');
+
+    expect(item.media!.text!.type, 'plain');
+    expect(item.media!.text!.lang, 'en');
+    expect(item.media!.text!.start, '00:00:03.000');
+    expect(item.media!.text!.end, '00:00:10.000');
+    expect(item.media!.text!.value, ' Oh, say, can you see');
+
+    expect(item.media!.restriction!.relationship, 'allow');
+    expect(item.media!.restriction!.type, 'country');
+    expect(item.media!.restriction!.value, 'au us');
+
+    expect(item.media!.community!.starRating!.average, 3.5);
+    expect(item.media!.community!.starRating!.count, 20);
+    expect(item.media!.community!.starRating!.min, 1);
+    expect(item.media!.community!.starRating!.max, 10);
+    expect(item.media!.community!.statistics!.views, 5);
+    expect(item.media!.community!.statistics!.favorites, 4);
+    expect(item.media!.community!.tags!.tags, 'news: 5, abc:3');
+    expect(item.media!.community!.tags!.weight, 1);
+
+    expect(item.media!.comments!.length, 2);
+    expect(item.media!.comments!.first, 'comment1');
+    expect(item.media!.comments!.last, 'comment2');
+
+    expect(item.media!.embed!.url, 'http://www.foo.com/player.swf');
+    expect(item.media!.embed!.width, 512);
+    expect(item.media!.embed!.height, 323);
+    expect(item.media!.embed!.params!.length, 5);
+    expect(item.media!.embed!.params!.first.name, 'type');
+    expect(item.media!.embed!.params!.first.value,
+        'application/x-shockwave-flash');
+
+    expect(item.media!.responses!.length, 2);
+    expect(item.media!.responses!.first, 'http://www.response1.com');
+    expect(item.media!.responses!.last, 'http://www.response2.com');
+
+    expect(item.media!.backLinks!.length, 2);
+    expect(item.media!.backLinks!.first, 'http://www.backlink1.com');
+    expect(item.media!.backLinks!.last, 'http://www.backlink2.com');
+
+    expect(item.media!.status!.state, 'active');
+    expect(item.media!.status!.reason, null);
+
+    expect(item.media!.prices!.length, 2);
+    expect(item.media!.prices!.first.price, 19.99);
+    expect(item.media!.prices!.first.type, 'rent');
+    expect(item.media!.prices!.first.info,
+        'http://www.dummy.jp/package_info.html');
+    expect(item.media!.prices!.first.currency, 'EUR');
+
+    expect(item.media!.license!.type, 'text/html');
+    expect(item.media!.license!.href, 'http://www.licensehost.com/license');
+    expect(item.media!.license!.value, ' Sample license for a video');
+
+    expect(item.media!.peerLink!.type, 'application/x-bittorrent');
+    expect(item.media!.peerLink!.href, 'http://www.foo.org/sampleFile.torrent');
+    expect(item.media!.peerLink!.value, '');
+
+    expect(item.media!.rights!.status, 'official');
+
+    expect(item.media!.scenes!.length, 2);
+    expect(item.media!.scenes!.first.title, 'sceneTitle1');
+    expect(item.media!.scenes!.first.description, 'sceneDesc1');
+    expect(item.media!.scenes!.first.startTime, '00:15');
+    expect(item.media!.scenes!.first.endTime, '00:45');
   });
 
   test('parse Atom-Empty.xml', () {
@@ -232,25 +232,25 @@ void main() {
     expect(feed.id, null);
     expect(feed.title, null);
     expect(feed.updated, null);
-    expect(feed.links.length, 0);
-    expect(feed.authors.length, 0);
-    expect(feed.contributors.length, 0);
-    expect(feed.categories.length, 0);
+    expect(feed.links!.length, 0);
+    expect(feed.authors!.length, 0);
+    expect(feed.contributors!.length, 0);
+    expect(feed.categories!.length, 0);
     expect(feed.generator, null);
     expect(feed.icon, null);
     expect(feed.logo, null);
     expect(feed.subtitle, null);
 
-    expect(feed.items.length, 1);
-    var item = feed.items.first;
+    expect(feed.items!.length, 1);
+    var item = feed.items!.first;
 
-    expect(item.authors.length, 0);
+    expect(item.authors!.length, 0);
 
-    expect(item.links.length, 0);
+    expect(item.links!.length, 0);
 
-    expect(item.categories.length, 0);
+    expect(item.categories!.length, 0);
 
-    expect(item.contributors.length, 0);
+    expect(item.contributors!.length, 0);
 
     expect(item.published, null);
     expect(item.summary, null);

test/rss_test.dart

@@ -36,59 +36,59 @@ void main() {
     expect(feed.webMaster, 'webmaster@foo.bar.news');
     expect(feed.ttl, 60);
 
-    expect(feed.image.title, 'Foo bar News');
-    expect(feed.image.url, 'https://foo.bar.news/logo.gif');
-    expect(feed.image.link, 'https://foo.bar.news/');
-
-    expect(feed.cloud.domain, 'radio.foo.bar.news');
-    expect(feed.cloud.port, '80');
-    expect(feed.cloud.path, '/RPC2');
-    expect(feed.cloud.registerProcedure, 'foo.bar.rssPleaseNotify');
-    expect(feed.cloud.protocol, 'xml-rpc');
-
-    expect(feed.categories.length, 2);
-    expect(feed.categories[0].domain, null);
-    expect(feed.categories[0].value, 'Ipsum');
-    expect(feed.categories[1].domain, 'news');
-    expect(feed.categories[1].value, 'Lorem Ipsum');
-
-    expect(feed.skipDays.length, 3);
-    expect(feed.skipDays.contains('Monday'), true);
-    expect(feed.skipDays.contains('Tuesday'), true);
-    expect(feed.skipDays.contains('Sunday'), true);
-
-    expect(feed.skipHours.length, 5);
-    expect(feed.skipHours.contains(0), true);
-    expect(feed.skipHours.contains(1), true);
-    expect(feed.skipHours.contains(2), true);
-    expect(feed.skipHours.contains(3), true);
-    expect(feed.skipHours.contains(4), true);
-
-    expect(feed.items.length, 2);
-
-    expect(feed.items.first.title,
+    expect(feed.image!.title, 'Foo bar News');
+    expect(feed.image!.url, 'https://foo.bar.news/logo.gif');
+    expect(feed.image!.link, 'https://foo.bar.news/');
+
+    expect(feed.cloud!.domain, 'radio.foo.bar.news');
+    expect(feed.cloud!.port, '80');
+    expect(feed.cloud!.path, '/RPC2');
+    expect(feed.cloud!.registerProcedure, 'foo.bar.rssPleaseNotify');
+    expect(feed.cloud!.protocol, 'xml-rpc');
+
+    expect(feed.categories!.length, 2);
+    expect(feed.categories![0].domain, null);
+    expect(feed.categories![0].value, 'Ipsum');
+    expect(feed.categories![1].domain, 'news');
+    expect(feed.categories![1].value, 'Lorem Ipsum');
+
+    expect(feed.skipDays!.length, 3);
+    expect(feed.skipDays!.contains('Monday'), true);
+    expect(feed.skipDays!.contains('Tuesday'), true);
+    expect(feed.skipDays!.contains('Sunday'), true);
+
+    expect(feed.skipHours!.length, 5);
+    expect(feed.skipHours!.contains(0), true);
+    expect(feed.skipHours!.contains(1), true);
+    expect(feed.skipHours!.contains(2), true);
+    expect(feed.skipHours!.contains(3), true);
+    expect(feed.skipHours!.contains(4), true);
+
+    expect(feed.items!.length, 2);
+
+    expect(feed.items!.first.title,
         'The standard Lorem Ipsum passage, used since the 1500s');
-    expect(feed.items.first.description,
+    expect(feed.items!.first.description,
         'Lorem ipsum dolor sit amet, consectetur adipiscing elit');
-    expect(feed.items.first.link, 'https://foo.bar.news/1');
-    expect(feed.items.first.guid, 'https://foo.bar.news/1?guid');
-    expect(feed.items.first.pubDate,
+    expect(feed.items!.first.link, 'https://foo.bar.news/1');
+    expect(feed.items!.first.guid, 'https://foo.bar.news/1?guid');
+    expect(feed.items!.first.pubDate,
         DateTime(2018, 03, 26, 14)); //Mon, 26 Mar 2018 14:00:00 PDT
-    expect(feed.items.first.categories.first.domain, 'news');
-    expect(feed.items.first.categories.first.value, 'Lorem');
-    expect(feed.items.first.author, 'alice@foo.bar.news');
-    expect(feed.items.first.source.url, 'https://foo.bar.news/1?source');
-    expect(feed.items.first.source.value, 'Foo Bar');
-    expect(feed.items.first.comments, 'https://foo.bar.news/1/comments');
-    expect(feed.items.first.enclosure.url,
+    expect(feed.items!.first.categories!.first.domain, 'news');
+    expect(feed.items!.first.categories!.first.value, 'Lorem');
+    expect(feed.items!.first.author, 'alice@foo.bar.news');
+    expect(feed.items!.first.source!.url, 'https://foo.bar.news/1?source');
+    expect(feed.items!.first.source!.value, 'Foo Bar');
+    expect(feed.items!.first.comments, 'https://foo.bar.news/1/comments');
+    expect(feed.items!.first.enclosure!.url,
         'http://www.scripting.com/mp3s/weatherReportSuite.mp3');
-    expect(feed.items.first.enclosure.length, 12216320);
-    expect(feed.items.first.enclosure.type, 'audio/mpeg');
+    expect(feed.items!.first.enclosure!.length, 12216320);
+    expect(feed.items!.first.enclosure!.type, 'audio/mpeg');
 
-    expect(feed.items.first.content.value,
+    expect(feed.items!.first.content!.value,
         '<img width="1000" height="690" src="https://test.com/image_link"/> Test content<br />');
     expect(
-        feed.items.first.content.images.first, 'https://test.com/image_link');
+        feed.items!.first.content!.images.first, 'https://test.com/image_link');
   });
   test('parse RSS-Media.xml', () {
     var xmlString = File('test/xml/RSS-Media.xml').readAsStringSync();
@@ -98,21 +98,21 @@ void main() {
     expect(
         feed.description, 'Media RSS example with new fields added in v1.5.0');
 
-    expect(feed.items.length, 1);
+    expect(feed.items!.length, 1);
 
-    var item = feed.items.first;
+    var item = feed.items!.first;
     expect(item.title, null);
     expect(item.link, 'http://www.foo.com');
     expect(item.pubDate,
         DateTime(2001, 08, 27, 16, 08, 56)); //Mon, 27 Aug 2001 16:08:56 PST
 
-    expect(item.media.group.contents.length, 5);
-    expect(item.media.group.credits.length, 2);
-    expect(item.media.group.category.value, 'music/artist name/album/song');
-    expect(item.media.group.rating.value, 'nonadult');
+    expect(item.media!.group!.contents!.length, 5);
+    expect(item.media!.group!.credits!.length, 2);
+    expect(item.media!.group!.category!.value, 'music/artist name/album/song');
+    expect(item.media!.group!.rating!.value, 'nonadult');
 
-    expect(item.media.contents.length, 2);
-    var mediaContent = item.media.contents.first;
+    expect(item.media!.contents!.length, 2);
+    var mediaContent = item.media!.contents!.first;
     expect(mediaContent.url, 'http://www.foo.com/video.mov');
     expect(mediaContent.type, 'video/quicktime');
     expect(mediaContent.fileSize, 2000);
@@ -124,152 +124,152 @@ void main() {
     expect(mediaContent.samplingrate, 44.1);
     expect(mediaContent.channels, 2);
 
-    expect(item.media.credits.length, 2);
-    var mediaCredit = item.media.credits.first;
+    expect(item.media!.credits!.length, 2);
+    var mediaCredit = item.media!.credits!.first;
     expect(mediaCredit.role, 'owner1');
     expect(mediaCredit.scheme, 'urn:yvs');
     expect(mediaCredit.value, 'copyright holder of the entity');
 
-    expect(item.media.category.scheme,
+    expect(item.media!.category!.scheme,
         'http://search.yahoo.com/mrss/category_ schema');
-    expect(item.media.category.label, 'Music');
-    expect(item.media.category.value, 'music/artist/album/song');
+    expect(item.media!.category!.label, 'Music');
+    expect(item.media!.category!.value, 'music/artist/album/song');
 
-    expect(item.media.rating.scheme, 'urn:simple');
-    expect(item.media.rating.value, 'adult');
+    expect(item.media!.rating!.scheme, 'urn:simple');
+    expect(item.media!.rating!.value, 'adult');
 
-    expect(item.media.title.type, 'plain');
-    expect(item.media.title.value, "The Judy's -- The Moo Song");
+    expect(item.media!.title!.type, 'plain');
+    expect(item.media!.title!.value, "The Judy's -- The Moo Song");
 
-    expect(item.media.description.type, 'plain');
-    expect(item.media.description.value,
+    expect(item.media!.description!.type, 'plain');
+    expect(item.media!.description!.value,
         'This was some really bizarre band I listened to as a young lad.');
 
-    expect(item.media.keywords, 'kitty, cat, big dog, yarn, fluffy');
+    expect(item.media!.keywords, 'kitty, cat, big dog, yarn, fluffy');
 
-    expect(item.media.thumbnails.length, 2);
-    var mediaThumbnail = item.media.thumbnails.first;
+    expect(item.media!.thumbnails!.length, 2);
+    var mediaThumbnail = item.media!.thumbnails!.first;
     expect(mediaThumbnail.url, 'http://www.foo.com/keyframe1.jpg');
     expect(mediaThumbnail.width, '75');
     expect(mediaThumbnail.height, '50');
     expect(mediaThumbnail.time, '12:05:01.123');
 
-    expect(item.media.hash.algo, 'md5');
-    expect(item.media.hash.value, 'dfdec888b72151965a34b4b59031290a');
-
-    expect(item.media.player.url, 'http://www.foo.com/player?id=1111');
-    expect(item.media.player.width, 400);
-    expect(item.media.player.height, 200);
-    expect(item.media.player.value, '');
-
-    expect(item.media.copyright.url, 'http://blah.com/additional-info.html');
-    expect(item.media.copyright.value, '2005 FooBar Media');
-
-    expect(item.media.text.type, 'plain');
-    expect(item.media.text.lang, 'en');
-    expect(item.media.text.start, '00:00:03.000');
-    expect(item.media.text.end, '00:00:10.000');
-    expect(item.media.text.value, ' Oh, say, can you see');
-
-    expect(item.media.restriction.relationship, 'allow');
-    expect(item.media.restriction.type, 'country');
-    expect(item.media.restriction.value, 'au us');
-
-    expect(item.media.community.starRating.average, 3.5);
-    expect(item.media.community.starRating.count, 20);
-    expect(item.media.community.starRating.min, 1);
-    expect(item.media.community.starRating.max, 10);
-    expect(item.media.community.statistics.views, 5);
-    expect(item.media.community.statistics.favorites, 4);
-    expect(item.media.community.tags.tags, 'news: 5, abc:3');
-    expect(item.media.community.tags.weight, 1);
-
-    expect(item.media.comments.length, 2);
-    expect(item.media.comments.first, 'comment1');
-    expect(item.media.comments.last, 'comment2');
-
-    expect(item.media.embed.url, 'http://www.foo.com/player.swf');
-    expect(item.media.embed.width, 512);
-    expect(item.media.embed.height, 323);
-    expect(item.media.embed.params.length, 5);
-    expect(item.media.embed.params.first.name, 'type');
-    expect(
-        item.media.embed.params.first.value, 'application/x-shockwave-flash');
-
-    expect(item.media.responses.length, 2);
-    expect(item.media.responses.first, 'http://www.response1.com');
-    expect(item.media.responses.last, 'http://www.response2.com');
-
-    expect(item.media.backLinks.length, 2);
-    expect(item.media.backLinks.first, 'http://www.backlink1.com');
-    expect(item.media.backLinks.last, 'http://www.backlink2.com');
-
-    expect(item.media.status.state, 'active');
-    expect(item.media.status.reason, null);
-
-    expect(item.media.prices.length, 2);
-    expect(item.media.prices.first.price, 19.99);
-    expect(item.media.prices.first.type, 'rent');
-    expect(
-        item.media.prices.first.info, 'http://www.dummy.jp/package_info.html');
-    expect(item.media.prices.first.currency, 'EUR');
-
-    expect(item.media.license.type, 'text/html');
-    expect(item.media.license.href, 'http://www.licensehost.com/license');
-    expect(item.media.license.value, ' Sample license for a video');
-
-    expect(item.media.peerLink.type, 'application/x-bittorrent');
-    expect(item.media.peerLink.href, 'http://www.foo.org/sampleFile.torrent');
-    expect(item.media.peerLink.value, '');
-
-    expect(item.media.rights.status, 'official');
-
-    expect(item.media.scenes.length, 2);
-    expect(item.media.scenes.first.title, 'sceneTitle1');
-    expect(item.media.scenes.first.description, 'sceneDesc1');
-    expect(item.media.scenes.first.startTime, '00:15');
-    expect(item.media.scenes.first.endTime, '00:45');
+    expect(item.media!.hash!.algo, 'md5');
+    expect(item.media!.hash!.value, 'dfdec888b72151965a34b4b59031290a');
+
+    expect(item.media!.player!.url, 'http://www.foo.com/player?id=1111');
+    expect(item.media!.player!.width, 400);
+    expect(item.media!.player!.height, 200);
+    expect(item.media!.player!.value, '');
+
+    expect(item.media!.copyright!.url, 'http://blah.com/additional-info.html');
+    expect(item.media!.copyright!.value, '2005 FooBar Media');
+
+    expect(item.media!.text!.type, 'plain');
+    expect(item.media!.text!.lang, 'en');
+    expect(item.media!.text!.start, '00:00:03.000');
+    expect(item.media!.text!.end, '00:00:10.000');
+    expect(item.media!.text!.value, ' Oh, say, can you see');
+
+    expect(item.media!.restriction!.relationship, 'allow');
+    expect(item.media!.restriction!.type, 'country');
+    expect(item.media!.restriction!.value, 'au us');
+
+    expect(item.media!.community!.starRating!.average, 3.5);
+    expect(item.media!.community!.starRating!.count, 20);
+    expect(item.media!.community!.starRating!.min, 1);
+    expect(item.media!.community!.starRating!.max, 10);
+    expect(item.media!.community!.statistics!.views, 5);
+    expect(item.media!.community!.statistics!.favorites, 4);
+    expect(item.media!.community!.tags!.tags, 'news: 5, abc:3');
+    expect(item.media!.community!.tags!.weight, 1);
+
+    expect(item.media!.comments!.length, 2);
+    expect(item.media!.comments!.first, 'comment1');
+    expect(item.media!.comments!.last, 'comment2');
+
+    expect(item.media!.embed!.url, 'http://www.foo.com/player.swf');
+    expect(item.media!.embed!.width, 512);
+    expect(item.media!.embed!.height, 323);
+    expect(item.media!.embed!.params!.length, 5);
+    expect(item.media!.embed!.params!.first.name, 'type');
+    expect(item.media!.embed!.params!.first.value,
+        'application/x-shockwave-flash');
+
+    expect(item.media!.responses!.length, 2);
+    expect(item.media!.responses!.first, 'http://www.response1.com');
+    expect(item.media!.responses!.last, 'http://www.response2.com');
+
+    expect(item.media!.backLinks!.length, 2);
+    expect(item.media!.backLinks!.first, 'http://www.backlink1.com');
+    expect(item.media!.backLinks!.last, 'http://www.backlink2.com');
+
+    expect(item.media!.status!.state, 'active');
+    expect(item.media!.status!.reason, null);
+
+    expect(item.media!.prices!.length, 2);
+    expect(item.media!.prices!.first.price, 19.99);
+    expect(item.media!.prices!.first.type, 'rent');
+    expect(item.media!.prices!.first.info,
+        'http://www.dummy.jp/package_info.html');
+    expect(item.media!.prices!.first.currency, 'EUR');
+
+    expect(item.media!.license!.type, 'text/html');
+    expect(item.media!.license!.href, 'http://www.licensehost.com/license');
+    expect(item.media!.license!.value, ' Sample license for a video');
+
+    expect(item.media!.peerLink!.type, 'application/x-bittorrent');
+    expect(item.media!.peerLink!.href, 'http://www.foo.org/sampleFile.torrent');
+    expect(item.media!.peerLink!.value, '');
+
+    expect(item.media!.rights!.status, 'official');
+
+    expect(item.media!.scenes!.length, 2);
+    expect(item.media!.scenes!.first.title, 'sceneTitle1');
+    expect(item.media!.scenes!.first.description, 'sceneDesc1');
+    expect(item.media!.scenes!.first.startTime, '00:15');
+    expect(item.media!.scenes!.first.endTime, '00:45');
   });
   test('parse RSS-DC.xml', () {
     var xmlString = File('test/xml/RSS-DC.xml').readAsStringSync();
 
     var feed = RssFeed.parse(xmlString);
 
-    expect(feed.dc.title, 'title');
-    expect(feed.dc.creator, 'creator');
-    expect(feed.dc.subject, 'subject');
-    expect(feed.dc.description, 'description');
-    expect(feed.dc.publisher, 'publisher');
-    expect(feed.dc.contributor, 'contributor');
-    expect(feed.dc.date, DateTime.utc(2000, 1, 1, 12));
-    expect(feed.dc.created, DateTime.utc(2000, 1, 1, 13));
-    expect(feed.dc.modified, DateTime.utc(2000, 1, 1, 14));
-    expect(feed.dc.type, 'type');
-    expect(feed.dc.format, 'format');
-    expect(feed.dc.identifier, 'identifier');
-    expect(feed.dc.source, 'source');
-    expect(feed.dc.language, 'language');
-    expect(feed.dc.relation, 'relation');
-    expect(feed.dc.coverage, 'coverage');
-    expect(feed.dc.rights, 'rights');
-
-    expect(feed.items.first.dc.title, 'title');
-    expect(feed.items.first.dc.creator, 'creator');
-    expect(feed.items.first.dc.subject, 'subject');
-    expect(feed.items.first.dc.description, 'description');
-    expect(feed.items.first.dc.publisher, 'publisher');
-    expect(feed.items.first.dc.contributor, 'contributor');
-    expect(feed.items.first.dc.date, DateTime.utc(2000, 1, 2, 12));
-    expect(feed.items.first.dc.created, DateTime.utc(2000, 1, 2, 13));
-    expect(feed.items.first.dc.modified, DateTime.utc(2000, 1, 2, 14));
-    expect(feed.items.first.dc.type, 'type');
-    expect(feed.items.first.dc.format, 'format');
-    expect(feed.items.first.dc.identifier, 'identifier');
-    expect(feed.items.first.dc.source, 'source');
-    expect(feed.items.first.dc.language, 'language');
-    expect(feed.items.first.dc.relation, 'relation');
-    expect(feed.items.first.dc.coverage, 'coverage');
-    expect(feed.items.first.dc.rights, 'rights');
+    expect(feed.dc!.title, 'title');
+    expect(feed.dc!.creator, 'creator');
+    expect(feed.dc!.subject, 'subject');
+    expect(feed.dc!.description, 'description');
+    expect(feed.dc!.publisher, 'publisher');
+    expect(feed.dc!.contributor, 'contributor');
+    expect(feed.dc!.date, DateTime.utc(2000, 1, 1, 12));
+    expect(feed.dc!.created, DateTime.utc(2000, 1, 1, 13));
+    expect(feed.dc!.modified, DateTime.utc(2000, 1, 1, 14));
+    expect(feed.dc!.type, 'type');
+    expect(feed.dc!.format, 'format');
+    expect(feed.dc!.identifier, 'identifier');
+    expect(feed.dc!.source, 'source');
+    expect(feed.dc!.language, 'language');
+    expect(feed.dc!.relation, 'relation');
+    expect(feed.dc!.coverage, 'coverage');
+    expect(feed.dc!.rights, 'rights');
+
+    expect(feed.items!.first.dc!.title, 'title');
+    expect(feed.items!.first.dc!.creator, 'creator');
+    expect(feed.items!.first.dc!.subject, 'subject');
+    expect(feed.items!.first.dc!.description, 'description');
+    expect(feed.items!.first.dc!.publisher, 'publisher');
+    expect(feed.items!.first.dc!.contributor, 'contributor');
+    expect(feed.items!.first.dc!.date, DateTime.utc(2000, 1, 2, 12));
+    expect(feed.items!.first.dc!.created, DateTime.utc(2000, 1, 2, 13));
+    expect(feed.items!.first.dc!.modified, DateTime.utc(2000, 1, 2, 14));
+    expect(feed.items!.first.dc!.type, 'type');
+    expect(feed.items!.first.dc!.format, 'format');
+    expect(feed.items!.first.dc!.identifier, 'identifier');
+    expect(feed.items!.first.dc!.source, 'source');
+    expect(feed.items!.first.dc!.language, 'language');
+    expect(feed.items!.first.dc!.relation, 'relation');
+    expect(feed.items!.first.dc!.coverage, 'coverage');
+    expect(feed.items!.first.dc!.rights, 'rights');
   });
 
   test('parse RSS-Empty.xml', () {
@@ -294,26 +294,26 @@ void main() {
 
     expect(feed.cloud, null);
 
-    expect(feed.categories.length, 0);
+    expect(feed.categories!.length, 0);
 
-    expect(feed.skipDays.length, 0);
+    expect(feed.skipDays!.length, 0);
 
-    expect(feed.skipHours.length, 0);
+    expect(feed.skipHours!.length, 0);
 
-    expect(feed.items.length, 1);
+    expect(feed.items!.length, 1);
 
-    expect(feed.items.first.title, null);
-    expect(feed.items.first.description, null);
-    expect(feed.items.first.link, null);
-    expect(feed.items.first.guid, null);
-    expect(feed.items.first.pubDate, null);
-    expect(feed.items.first.categories.length, 0);
-    expect(feed.items.first.author, null);
-    expect(feed.items.first.source, null);
-    expect(feed.items.first.comments, null);
-    expect(feed.items.first.enclosure, null);
+    expect(feed.items!.first.title, null);
+    expect(feed.items!.first.description, null);
+    expect(feed.items!.first.link, null);
+    expect(feed.items!.first.guid, null);
+    expect(feed.items!.first.pubDate, null);
+    expect(feed.items!.first.categories!.length, 0);
+    expect(feed.items!.first.author, null);
+    expect(feed.items!.first.source, null);
+    expect(feed.items!.first.comments, null);
+    expect(feed.items!.first.enclosure, null);
 
-    expect(feed.items.first.content, null);
+    expect(feed.items!.first.content, null);
   });
 
   test('parse RSS-Itunes.xml', () {
@@ -321,22 +321,22 @@ void main() {
 
     var feed = RssFeed.parse(xmlString);
 
-    expect(feed.itunes.author, 'Changelog Media');
-    expect(feed.itunes.summary, 'Foo');
-    expect(feed.itunes.explicit, false);
-    expect(feed.itunes.image.href,
+    expect(feed.itunes!.author, 'Changelog Media');
+    expect(feed.itunes!.summary, 'Foo');
+    expect(feed.itunes!.explicit, false);
+    expect(feed.itunes!.image!.href,
         'https://cdn.changelog.com/uploads/covers/go-time-original.png?v=63725770357');
-    expect(feed.itunes.keywords,
+    expect(feed.itunes!.keywords,
         'go,golang,open source,software,development'.split(','));
-    expect(feed.itunes.owner.name, 'Changelog Media');
-    expect(feed.itunes.owner.email, 'editors@changelog.com');
+    expect(feed.itunes!.owner!.name, 'Changelog Media');
+    expect(feed.itunes!.owner!.email, 'editors@changelog.com');
     expect(
         Set.from([
-          feed.itunes.categories[0].category,
-          feed.itunes.categories[1].category
+          feed.itunes!.categories![0].category,
+          feed.itunes!.categories![1].category
         ]),
         ['Technology', 'Foo']);
-    for (var category in feed.itunes.categories) {
+    for (var category in feed.itunes!.categories!) {
       switch (category.category) {
         case 'Foo':
           expect(category.subCategories, ['Bar', 'Baz']);
@@ -346,29 +346,29 @@ void main() {
           break;
       }
     }
-    expect(feed.itunes.title, 'Go Time');
-    expect(feed.itunes.type, ItunesType.serial);
-    expect(feed.itunes.newFeedUrl, 'wubawuba');
-    expect(feed.itunes.block, true);
-    expect(feed.itunes.complete, true);
-
-    var item = feed.items[0];
-    expect(item.itunes.episodeType, ItunesEpisodeType.full);
-    expect(item.itunes.episode, 1);
-    expect(item.itunes.season, 1);
-    expect(item.itunes.image.href,
+    expect(feed.itunes!.title, 'Go Time');
+    expect(feed.itunes!.type, ItunesType.serial);
+    expect(feed.itunes!.newFeedUrl, 'wubawuba');
+    expect(feed.itunes!.block, true);
+    expect(feed.itunes!.complete, true);
+
+    var item = feed.items![0];
+    expect(item.itunes!.episodeType, ItunesEpisodeType.full);
+    expect(item.itunes!.episode, 1);
+    expect(item.itunes!.season, 1);
+    expect(item.itunes!.image!.href,
         'https://cdn.changelog.com/uploads/covers/go-time-original.png?v=63725770357');
-    expect(item.itunes.duration, Duration(minutes: 32, seconds: 30));
-    expect(item.itunes.explicit, false);
-    expect(item.itunes.keywords,
+    expect(item.itunes!.duration, Duration(minutes: 32, seconds: 30));
+    expect(item.itunes!.explicit, false);
+    expect(item.itunes!.keywords,
         'go,golang,open source,software,development'.split(','));
-    expect(item.itunes.subtitle, 'with Erik, Carlisia, and Brian');
-    expect(item.itunes.summary, 'Foo');
-    expect(item.itunes.author,
+    expect(item.itunes!.subtitle, 'with Erik, Carlisia, and Brian');
+    expect(item.itunes!.summary, 'Foo');
+    expect(item.itunes!.author,
         'Erik St. Martin, Carlisia Pinto, and Brian Ketelsen');
-    expect(item.itunes.explicit, false);
-    expect(item.itunes.title, 'awesome title');
-    expect(item.itunes.block, false);
+    expect(item.itunes!.explicit, false);
+    expect(item.itunes!.title, 'awesome title');
+    expect(item.itunes!.block, false);
   });
 
   test('parse RSS-Itunes_item_empty_field.xml with empty duration field', () {
@@ -391,12 +391,12 @@ void main() {
     expect(feed.title, 'Mozilla Dot Org');
     expect(feed.link, 'http://www.mozilla.org');
     expect(feed.description, 'the Mozilla Organization web site');
-    expect(feed.image.title, 'Mozilla');
-    expect(feed.image.url, 'http://www.mozilla.org/images/moz.gif');
-    expect(feed.image.link, 'http://www.mozilla.org');
-    expect(feed.items.length, 5);
-    expect(feed.items.first.title, 'New Status Updates');
-    expect(feed.items.first.link, 'http://www.mozilla.org/status/');
+    expect(feed.image!.title, 'Mozilla');
+    expect(feed.image!.url, 'http://www.mozilla.org/images/moz.gif');
+    expect(feed.image!.link, 'http://www.mozilla.org');
+    expect(feed.items!.length, 5);
+    expect(feed.items!.first.title, 'New Status Updates');
+    expect(feed.items!.first.link, 'http://www.mozilla.org/status/');
   });
 
   test('parse RSS-Syndication.xml', () {
@@ -407,17 +407,17 @@ void main() {
     expect(feed.title, 'Meerkat');
     expect(feed.link, 'http://meerkat.oreillynet.com');
     expect(feed.description, 'Meerkat: An Open Wire Service');
-    expect(feed.image.title, 'Meerkat Powered!');
-    expect(feed.image.url,
+    expect(feed.image!.title, 'Meerkat Powered!');
+    expect(feed.image!.url,
         'http://meerkat.oreillynet.com/icons/meerkat-powered.jpg');
-    expect(feed.image.link, 'http://meerkat.oreillynet.com');
-    expect(feed.syndication.updatePeriod, SyndicationUpdatePeriod.hourly);
-    expect(feed.syndication.updateFrequency, 2);
-    expect(feed.syndication.updateBase, DateTime.utc(2001, 1, 1, 12, 1));
-    expect(feed.items.length, 1);
-    expect(feed.items.first.title, 'XML: A Disruptive Technology');
-    expect(feed.items.first.description,
+    expect(feed.image!.link, 'http://meerkat.oreillynet.com');
+    expect(feed.syndication!.updatePeriod, SyndicationUpdatePeriod.hourly);
+    expect(feed.syndication!.updateFrequency, 2);
+    expect(feed.syndication!.updateBase, DateTime.utc(2001, 1, 1, 12, 1));
+    expect(feed.items!.length, 1);
+    expect(feed.items!.first.title, 'XML: A Disruptive Technology');
+    expect(feed.items!.first.description,
         'XML is placing increasingly heavy loads on the existing technical infrastructure of the Internet.');
-    expect(feed.items.first.link, 'http://c.moreover.com/click/here.pl?r123');
+    expect(feed.items!.first.link, 'http://c.moreover.com/click/here.pl?r123');
   });
 }