mcs/class/System.ServiceModel.Web/System.ServiceModel.Syndication/SyndicationVersions.cs

   1 //
   2 // SyndicationVersions.cs
   3 //
   4 // Author:
   5 //      Atsushi Enomoto  <atsushi@ximian.com>
   6 //
   7 // Copyright (C) 2007 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28 using System;
  29 using System.Collections.Generic;
  30 using System.Collections.ObjectModel;
  31 using System.IO;
  32 using System.Runtime.Serialization;
  33 using System.Text;
  34 using System.Xml;
  35
  36 namespace System.ServiceModel.Syndication
  37 {
  38         public static class SyndicationVersions
  39         {
  40                 private enum ReaderKind
  41                 {
  42                         Item,
  43                         Feed,
  44                 }
  45
  46                 public const string Atom10 = "Atom10";
  47                 public const string Rss20 = "Rss20";
  48
  49                 const string AtomNamespace ="http://www.w3.org/2005/Atom";
  50
  51                 static string DetectVersion (XmlReader reader, ReaderKind kind)
  52                 {
  53                         if (reader == null)
  54                                 throw new ArgumentNullException ("reader");
  55                         reader.MoveToContent ();
  56                         if (reader.NodeType != XmlNodeType.Element)
  57                                 throw new XmlException ("An element is expected for syndication item");
  58                         if (reader.IsStartElement ("rss", String.Empty) && reader.GetAttribute ("version") == "2.0")
  59                                 return SyndicationVersions.Rss20;
  60                         if ((kind == ReaderKind.Item && reader.IsStartElement ("entry", AtomNamespace)) ||
  61                             (kind == ReaderKind.Feed && reader.IsStartElement("feed", AtomNamespace)))
  62                                 return SyndicationVersions.Atom10;
  63                         else if (reader.IsStartElement ("item", String.Empty))
  64                                 return SyndicationVersions.Rss20;
  65                         else
  66                                 throw new XmlException (String.Format ("Unexpected syndication item element: name is '{0}' and namespace is '{1}'", reader.LocalName, reader.NamespaceURI));
  67                 }
  68
  69                 internal static TSyndicationFeed LoadFeed<TSyndicationFeed> (XmlReader reader) where TSyndicationFeed : SyndicationFeed, new()
  70                 {
  71                         switch (DetectVersion (reader, ReaderKind.Feed)) {
  72                         case SyndicationVersions.Atom10:
  73                                 Atom10FeedFormatter af = new Atom10FeedFormatter<TSyndicationFeed> ();
  74                                 af.ReadFrom (reader);
  75                                 return (TSyndicationFeed) af.Feed;
  76                         case SyndicationVersions.Rss20:
  77                         default: // anything else are rejected by DetectVersion
  78                                 Rss20FeedFormatter rf = new Rss20FeedFormatter<TSyndicationFeed> ();
  79                                 rf.ReadFrom (reader);
  80                                 return (TSyndicationFeed) rf.Feed;
  81                         }
  82                 }
  83
  84                 internal static TSyndicationItem LoadItem<TSyndicationItem> (XmlReader reader) where TSyndicationItem : SyndicationItem, new()
  85                 {
  86                         switch (DetectVersion (reader, ReaderKind.Item)) {
  87                         case SyndicationVersions.Atom10:
  88                                 Atom10ItemFormatter af = new Atom10ItemFormatter<TSyndicationItem> ();
  89                                 af.ReadFrom (reader);
  90                                 return (TSyndicationItem) af.Item;
  91                         case SyndicationVersions.Rss20:
  92                         default: // anything else are rejected by DetectVersion
  93                                 Rss20ItemFormatter rf = new Rss20ItemFormatter<TSyndicationItem> ();
  94                                 rf.ReadFrom (reader);
  95                                 return (TSyndicationItem) rf.Item;
  96                         }
  97                 }
  98         }
  99 }