support syndication namespace

lib/domain/rss_feed.dart

@@ -6,6 +6,7 @@ import 'package:webfeed/domain/rss_category.dart';
 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:xml/xml.dart';
 
@@ -32,6 +33,7 @@ class RssFeed {
   final int ttl;
   final DublinCore dc;
   final Itunes itunes;
+  final Syndication syndication;
 
   RssFeed({
     this.title,
@@ -55,6 +57,7 @@ class RssFeed {
     this.ttl,
     this.dc,
     this.itunes,
+    this.syndication,
   });
 
   factory RssFeed.parse(String xmlString) {
@@ -105,6 +108,7 @@ class RssFeed {
       ttl: int.tryParse(findFirstElement(channelElement, 'ttl')?.text ?? '0'),
       dc: DublinCore.parse(channelElement),
       itunes: Itunes.parse(channelElement),
+      syndication: Syndication.parse(channelElement),
     );
   }
 }

lib/domain/syndication/syndication.dart

@@ -0,0 +1,51 @@
+import 'package:webfeed/util/datetime.dart';
+import 'package:webfeed/util/xml.dart';
+import 'package:xml/xml.dart';
+
+enum SyndicationUpdatePeriod { hourly, daily, weekly, monthly, yearly }
+
+class Syndication {
+  final SyndicationUpdatePeriod updatePeriod;
+  final int updateFrequency;
+  final DateTime updateBase;
+
+  Syndication({
+    this.updatePeriod,
+    this.updateFrequency,
+    this.updateBase,
+  });
+
+  factory Syndication.parse(XmlElement element) {
+    if (element == null) {
+      return null;
+    }
+    SyndicationUpdatePeriod updatePeriod;
+    switch (findFirstElement(element, 'sy:updatePeriod')?.text) {
+      case 'hourly':
+        updatePeriod = SyndicationUpdatePeriod.hourly;
+        break;
+      case 'daily':
+        updatePeriod = SyndicationUpdatePeriod.daily;
+        break;
+      case 'weekly':
+        updatePeriod = SyndicationUpdatePeriod.weekly;
+        break;
+      case 'monthly':
+        updatePeriod = SyndicationUpdatePeriod.monthly;
+        break;
+      case 'yearly':
+        updatePeriod = SyndicationUpdatePeriod.yearly;
+        break;
+      default:
+        updatePeriod = SyndicationUpdatePeriod.daily;
+        break;
+    }
+    return Syndication(
+      updatePeriod: updatePeriod,
+      updateFrequency: int.tryParse(
+          findFirstElement(element, 'sy:updateFrequency')?.text ?? '1'),
+      updateBase:
+          parseDateTime(findFirstElement(element, 'sy:updateBase')?.text),
+    );
+  }
+}

test/rss_test.dart

@@ -4,6 +4,7 @@ import 'dart:io';
 import 'package:test/test.dart';
 import 'package:webfeed/domain/itunes/itunes_episode_type.dart';
 import 'package:webfeed/domain/itunes/itunes_type.dart';
+import 'package:webfeed/domain/syndication/syndication.dart';
 import 'package:webfeed/webfeed.dart';
 
 void main() {
@@ -385,4 +386,26 @@ void main() {
     expect(feed.items.first.title, 'New Status Updates');
     expect(feed.items.first.link, 'http://www.mozilla.org/status/');
   });
+
+  test('parse RSS-Syndication.xml', () {
+    var xmlString = File('test/xml/RSS-Syndication.xml').readAsStringSync();
+
+    var feed = RssFeed.parse(xmlString);
+
+    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,
+        '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,
+        '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');
+  });
 }

test/xml/RSS-Syndication.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
+         xmlns="http://purl.org/rss/1.0/">
+    <channel rdf:about="http://meerkat.oreillynet.com/?_fl=rss1.0">
+        <title>Meerkat</title>
+        <link>http://meerkat.oreillynet.com</link>
+        <description>Meerkat: An Open Wire Service</description>
+        <sy:updatePeriod>hourly</sy:updatePeriod>
+        <sy:updateFrequency>2</sy:updateFrequency>
+        <sy:updateBase>2001-01-01T12:01+00:00</sy:updateBase>
+        <image rdf:resource="http://meerkat.oreillynet.com/icons/meerkat-powered.jpg"/>
+    </channel>
+    <image rdf:about="http://meerkat.oreillynet.com/icons/meerkat-powered.jpg">
+        <title>Meerkat Powered!</title>
+        <url>http://meerkat.oreillynet.com/icons/meerkat-powered.jpg</url>
+        <link>http://meerkat.oreillynet.com</link>
+    </image>
+    <item rdf:about="http://c.moreover.com/click/here.pl?r123">
+        <title>XML: A Disruptive Technology</title>
+        <link>http://c.moreover.com/click/here.pl?r123</link>
+        <description>XML is placing increasingly heavy loads on the existing technical infrastructure of the Internet.</description>
+    </item>
+</rdf:RDF>