mcs/class/System.ServiceModel.Web/System.ServiceModel.Syndication/Rss20FeedFormatter.cs

   1 //
   2 // Rss20FeedFormatter.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.Globalization;
  32 using System.IO;
  33 using System.Runtime.Serialization;
  34 using System.Text;
  35 using System.Xml;
  36 using System.Xml.Schema;
  37 using System.Xml.Serialization;
  38
  39 namespace System.ServiceModel.Syndication
  40 {
  41         [XmlRoot ("rss", Namespace = "")]
  42         public class Rss20FeedFormatter : SyndicationFeedFormatter, IXmlSerializable
  43         {
  44                 const string AtomNamespace ="http://www.w3.org/2005/Atom";
  45
  46                 bool ext_atom_serialization, preserve_att_ext = true, preserve_elem_ext = true;
  47                 Type feed_type;
  48
  49                 public Rss20FeedFormatter ()
  50                 {
  51                         ext_atom_serialization = true;
  52                 }
  53
  54                 public Rss20FeedFormatter (SyndicationFeed feedToWrite)
  55                         : this (feedToWrite, true)
  56                 {
  57                 }
  58
  59                 public Rss20FeedFormatter (SyndicationFeed feedToWrite, bool serializeExtensionsAsAtom)
  60                         : base (feedToWrite)
  61                 {
  62                         ext_atom_serialization = serializeExtensionsAsAtom;
  63                 }
  64
  65                 public Rss20FeedFormatter (Type feedTypeToCreate)
  66                 {
  67                         if (feedTypeToCreate == null)
  68                                 throw new ArgumentNullException ("feedTypeToCreate");
  69                         feed_type = feedTypeToCreate;
  70                 }
  71
  72                 public bool SerializeExtensionsAsAtom {
  73                         get { return ext_atom_serialization; }
  74                         set { ext_atom_serialization = value; }
  75                 }
  76
  77                 protected Type FeedType {
  78                         get { return feed_type; }
  79                 }
  80
  81                 public bool PreserveAttributeExtensions {
  82                         get { return preserve_att_ext; }
  83                         set { preserve_att_ext = value; }
  84                 }
  85
  86                 public bool PreserveElementExtensions {
  87                         get { return preserve_elem_ext; }
  88                         set { preserve_elem_ext = value; }
  89                 }
  90
  91                 public override string Version {
  92                         get { return "Rss20"; }
  93                 }
  94
  95                 protected override SyndicationFeed CreateFeedInstance ()
  96                 {
  97                         return new SyndicationFeed ();
  98                 }
  99
 100                 // hmm, why is it overriden? probably failed API cleanup.
 101                 protected internal override void SetFeed (SyndicationFeed feed)
 102                 {
 103                         base.SetFeed (feed);
 104                 }
 105
 106                 public override bool CanRead (XmlReader reader)
 107                 {
 108                         if (reader == null)
 109                                 throw new ArgumentNullException ("reader");
 110                         reader.MoveToContent ();
 111                         return reader.IsStartElement ("rss", String.Empty);
 112                 }
 113
 114                 public override void ReadFrom (XmlReader reader)
 115                 {
 116                         if (!CanRead (reader))
 117                                 throw new XmlException (String.Format ("Element '{0}' in namespace '{1}' is not accepted by this syndication formatter", reader.LocalName, reader.NamespaceURI));
 118                         ReadXml (reader, true);
 119                 }
 120
 121                 protected virtual SyndicationItem ReadItem (XmlReader reader, SyndicationFeed feed)
 122                 {
 123                         Rss20ItemFormatter formatter = new Rss20ItemFormatter();
 124                         formatter.ReadFrom (reader);
 125                         return formatter.Item;
 126                 }
 127
 128                 protected virtual IEnumerable<SyndicationItem> ReadItems (XmlReader reader, SyndicationFeed feed, out bool areAllItemsRead)
 129                 {
 130                         Collection<SyndicationItem> c = new Collection<SyndicationItem> ();
 131                         for (reader.MoveToContent (); reader.NodeType != XmlNodeType.EndElement; reader.MoveToContent ())
 132                                 if (reader.LocalName == "item" && reader.NamespaceURI == String.Empty)
 133                                         c.Add (ReadItem (reader, feed));
 134                         areAllItemsRead = (reader.NodeType == XmlNodeType.EndElement);
 135                         return c;
 136                 }
 137
 138                 protected virtual void WriteItem (XmlWriter writer, SyndicationItem item, Uri feedBaseUri)
 139                 {
 140                         item.SaveAsRss20 (writer);
 141                 }
 142
 143                 protected virtual void WriteItems (XmlWriter writer, IEnumerable<SyndicationItem> items, Uri feedBaseUri)
 144                 {
 145                         if (items == null)
 146                                 throw new ArgumentNullException ("items");
 147                         foreach (SyndicationItem item in items)
 148                                 WriteItem (writer, item, feedBaseUri);
 149                 }
 150
 151                 public override void WriteTo (XmlWriter writer)
 152                 {
 153                         WriteXml (writer, true);
 154                 }
 155
 156                 void IXmlSerializable.ReadXml (XmlReader reader)
 157                 {
 158                         ReadXml (reader, false);
 159                 }
 160
 161                 void IXmlSerializable.WriteXml (XmlWriter writer)
 162                 {
 163                         WriteXml (writer, false);
 164                 }
 165
 166                 XmlSchema IXmlSerializable.GetSchema ()
 167                 {
 168                         return null;
 169                 }
 170
 171                 // read
 172
 173                 void ReadXml (XmlReader reader, bool fromSerializable)
 174                 {
 175                         if (reader == null)
 176                                 throw new ArgumentNullException ("reader");
 177                         SetFeed (CreateFeedInstance ());
 178
 179                         reader.MoveToContent ();
 180
 181                         string ver = reader.GetAttribute ("version");
 182                         if (ver != "2.0")
 183                                 throw new NotSupportedException (String.Format ("RSS Version '{0}' is not supported", ver));
 184
 185                         if (PreserveAttributeExtensions && reader.MoveToFirstAttribute ()) {
 186                                 do {
 187                                         if (reader.NamespaceURI == "http://www.w3.org/2000/xmlns/")
 188                                                 continue;
 189                                         if (reader.NamespaceURI == String.Empty && reader.LocalName == "version")
 190                                                 continue;
 191                                         if (!TryParseAttribute (reader.LocalName, reader.NamespaceURI, reader.Value, Feed, Version))
 192                                                 Feed.AttributeExtensions.Add (new XmlQualifiedName (reader.LocalName, reader.NamespaceURI), reader.Value);
 193                                 } while (reader.MoveToNextAttribute ());
 194                         }
 195
 196                         reader.ReadStartElement (); // <rss> => <channel>
 197                         reader.MoveToContent ();
 198                         reader.ReadStartElement ("channel", String.Empty); // <channel> => *
 199
 200                         Collection<SyndicationItem> items = null;
 201
 202                         for (reader.MoveToContent (); reader.NodeType != XmlNodeType.EndElement; reader.MoveToContent ()) {
 203                                 if (reader.NodeType != XmlNodeType.Element)
 204                                         throw new XmlException ("Only element node is expected under 'channel' element");
 205                                 if (reader.NamespaceURI == String.Empty)
 206                                         switch (reader.LocalName) {
 207                                         case "title":
 208                                                 Feed.Title = ReadTextSyndicationContent (reader);
 209                                                 continue;
 210                                         case "link":
 211                                                 SyndicationLink l = Feed.CreateLink ();
 212                                                 ReadLink (reader, l);
 213                                                 Feed.Links.Add (l);
 214                                                 continue;
 215                                         case "description":
 216                                                 Feed.Description = ReadTextSyndicationContent (reader);
 217                                                 continue;
 218                                         case "language":
 219                                                 Feed.Language = reader.ReadElementContentAsString ();
 220                                                 continue;
 221                                         case "copyright":
 222                                                 Feed.Copyright = ReadTextSyndicationContent (reader);
 223                                                 continue;
 224                                         case "managingEditor":
 225                                                 SyndicationPerson p = Feed.CreatePerson ();
 226                                                 ReadPerson (reader, p);
 227                                                 Feed.Authors.Add (p);
 228                                                 continue;
 229                                         case "pubDate":
 230                                                 // FIXME: somehow DateTimeOffset causes the runtime crash.
 231                                                 reader.ReadElementContentAsString ();
 232                                                 // Feed.PublishDate = FromRFC822DateString (reader.ReadElementContentAsString ());
 233                                                 continue;
 234                                         case "lastBuildDate":
 235                                                 // FIXME: somehow DateTimeOffset causes the runtime crash.
 236                                                 reader.ReadElementContentAsString ();
 237                                                 // Feed.LastUpdatedTime = FromRFC822DateString (reader.ReadElementContentAsString ());
 238                                                 continue;
 239                                         case "category":
 240                                                 SyndicationCategory c = Feed.CreateCategory ();
 241                                                 ReadCategory (reader, c);
 242                                                 Feed.Categories.Add (c);
 243                                                 continue;
 244                                         case "generator":
 245                                                 Feed.Generator = reader.ReadElementContentAsString ();
 246                                                 continue;
 247                                         //  "webMaster" "docs" "cloud" "ttl" "image" "rating" "textInput" "skipHours" "skipDays" are not handled.
 248                                         case "item":
 249                                                 if (items == null) {
 250                                                         items = new Collection<SyndicationItem> ();
 251                                                         Feed.Items = items;
 252                                                 }
 253                                                 items.Add (ReadItem (reader, Feed));
 254                                                 continue;
 255                                         }
 256                                 if (!TryParseElement (reader, Feed, Version)) {
 257                                         if (PreserveElementExtensions)
 258                                                 // FIXME: what to specify for maxExtensionSize
 259                                                 LoadElementExtensions (reader, Feed, int.MaxValue);
 260                                         else
 261                                                 reader.Skip ();
 262                                 }
 263                         }
 264
 265                         reader.ReadEndElement (); // </channel>
 266                         reader.ReadEndElement (); // </rss>
 267                 }
 268
 269                 TextSyndicationContent ReadTextSyndicationContent (XmlReader reader)
 270                 {
 271                         TextSyndicationContentKind kind = TextSyndicationContentKind.Plaintext;
 272                         switch (reader.GetAttribute ("type")) {
 273                         case "html":
 274                                 kind = TextSyndicationContentKind.Html;
 275                                 break;
 276                         case "xhtml":
 277                                 kind = TextSyndicationContentKind.XHtml;
 278                                 break;
 279                         }
 280                         string text = reader.ReadElementContentAsString ();
 281                         TextSyndicationContent t = new TextSyndicationContent (text, kind);
 282                         return t;
 283                 }
 284
 285                 void ReadCategory (XmlReader reader, SyndicationCategory category)
 286                 {
 287                         if (reader.MoveToFirstAttribute ()) {
 288                                 do {
 289                                         if (reader.NamespaceURI == "http://www.w3.org/2000/xmlns/")
 290                                                 continue;
 291                                         if (reader.NamespaceURI == String.Empty) {
 292                                                 switch (reader.LocalName) {
 293                                                 case "domain":
 294                                                         category.Scheme = reader.Value;
 295                                                         continue;
 296                                                 }
 297                                         }
 298                                         if (PreserveAttributeExtensions)
 299                                                 if (!TryParseAttribute (reader.LocalName, reader.NamespaceURI, reader.Value, category, Version))
 300                                                         category.AttributeExtensions.Add (new XmlQualifiedName (reader.LocalName, reader.NamespaceURI), reader.Value);
 301                                 } while (reader.MoveToNextAttribute ());
 302                                 reader.MoveToElement ();
 303                         }
 304
 305                         if (!reader.IsEmptyElement) {
 306                                 reader.Read ();
 307                                 for (reader.MoveToContent (); reader.NodeType != XmlNodeType.EndElement; reader.MoveToContent ()) {
 308                                         if (reader.IsTextNode ())
 309                                                 category.Name += reader.Value;
 310                                         else if (!TryParseElement (reader, category, Version)) {
 311                                                 if (PreserveElementExtensions)
 312                                                         // FIXME: what should be used for maxExtenswionSize
 313                                                         LoadElementExtensions (reader, category, int.MaxValue);
 314                                                 else
 315                                                         reader.Skip ();
 316                                         }
 317                                         reader.Read ();
 318                                 }
 319                         }
 320                         reader.Read (); // </category> or <category ... />
 321                 }
 322
 323                 void ReadLink (XmlReader reader, SyndicationLink link)
 324                 {
 325                         if (PreserveAttributeExtensions && reader.MoveToFirstAttribute ()) {
 326                                 do {
 327                                         if (reader.NamespaceURI == "http://www.w3.org/2000/xmlns/")
 328                                                 continue;
 329                                         if (!TryParseAttribute (reader.LocalName, reader.NamespaceURI, reader.Value, link, Version))
 330                                                 link.AttributeExtensions.Add (new XmlQualifiedName (reader.LocalName, reader.NamespaceURI), reader.Value);
 331                                 } while (reader.MoveToNextAttribute ());
 332                                 reader.MoveToElement ();
 333                         }
 334
 335                         if (!reader.IsEmptyElement) {
 336                                 string url = null;
 337                                 reader.Read ();
 338                                 for (reader.MoveToContent (); reader.NodeType != XmlNodeType.EndElement; reader.MoveToContent ()) {
 339                                         if (reader.IsTextNode ())
 340                                                 url += reader.Value;
 341                                         else if (!TryParseElement (reader, link, Version)) {
 342                                                 if (PreserveElementExtensions)
 343                                                         // FIXME: what should be used for maxExtenswionSize
 344                                                         LoadElementExtensions (reader, link, int.MaxValue);
 345                                                 else
 346                                                         reader.Skip ();
 347                                         }
 348                                         reader.Read ();
 349                                 }
 350                                 link.Uri = CreateUri (url);
 351                         }
 352                         reader.Read (); // </link> or <link ... />
 353                 }
 354
 355                 void ReadPerson (XmlReader reader, SyndicationPerson person)
 356                 {
 357                         if (PreserveAttributeExtensions && reader.MoveToFirstAttribute ()) {
 358                                 do {
 359                                         if (reader.NamespaceURI == "http://www.w3.org/2000/xmlns/")
 360                                                 continue;
 361                                         if (!TryParseAttribute (reader.LocalName, reader.NamespaceURI, reader.Value, person, Version))
 362                                                 person.AttributeExtensions.Add (new XmlQualifiedName (reader.LocalName, reader.NamespaceURI), reader.Value);
 363                                 } while (reader.MoveToNextAttribute ());
 364                                 reader.MoveToElement ();
 365                         }
 366
 367                         if (!reader.IsEmptyElement) {
 368                                 reader.Read ();
 369                                 for (reader.MoveToContent (); reader.NodeType != XmlNodeType.EndElement; reader.MoveToContent ()) {
 370                                         if (reader.IsTextNode ())
 371                                                 person.Email += reader.Value;
 372                                         else if (!TryParseElement (reader, person, Version)) {
 373                                                 if (PreserveElementExtensions)
 374                                                         // FIXME: what should be used for maxExtenswionSize
 375                                                         LoadElementExtensions (reader, person, int.MaxValue);
 376                                                 else
 377                                                         reader.Skip ();
 378                                         }
 379                                         reader.Read ();
 380                                 }
 381                         }
 382                         reader.Read (); // end element or empty element
 383                 }
 384
 385                 Uri CreateUri (string uri)
 386                 {
 387                         return new Uri (uri, UriKind.RelativeOrAbsolute);
 388                 }
 389
 390                 // write
 391
 392                 void WriteXml (XmlWriter writer, bool writeRoot)
 393                 {
 394                         if (writer == null)
 395                                 throw new ArgumentNullException ("writer");
 396                         if (Feed == null)
 397                                 throw new InvalidOperationException ("Syndication feed must be set before writing");
 398
 399                         if (writeRoot)
 400                                 writer.WriteStartElement ("rss");
 401
 402                         if (SerializeExtensionsAsAtom)
 403                                 writer.WriteAttributeString ("xmlns", "a10", "http://www.w3.org/2000/xmlns/", AtomNamespace);
 404                         writer.WriteAttributeString ("version", "2.0");
 405
 406                         writer.WriteStartElement ("channel");
 407
 408                         if (Feed.BaseUri != null)
 409                                 writer.WriteAttributeString ("xml:base", Feed.BaseUri.ToString ());
 410
 411                         writer.WriteElementString ("title", String.Empty, Feed.Title != null ? Feed.Title.Text : String.Empty);
 412
 413                         writer.WriteElementString ("description", String.Empty, Feed.Description != null ? Feed.Description.Text : String.Empty);
 414
 415                         if (Feed.Copyright != null)
 416                                 writer.WriteElementString ("copyright", String.Empty, Feed.Copyright.Text);
 417
 418                         if (!Feed.LastUpdatedTime.Equals (default (DateTimeOffset))) {
 419                                 writer.WriteStartElement ("lastBuildDate");
 420                                 writer.WriteString (ToRFC822DateString (Feed.LastUpdatedTime));
 421                                 writer.WriteEndElement ();
 422                         }
 423
 424                         if (Feed.Generator != null)
 425                                 writer.WriteElementString ("generator", String.Empty, Feed.Generator);
 426                         if (Feed.ImageUrl != null) {
 427                                 writer.WriteStartElement ("image");
 428                                 writer.WriteElementString ("url", String.Empty, Feed.ImageUrl.ToString ());
 429                                 // FIXME: are they really empty?
 430                                 writer.WriteElementString ("title", String.Empty, String.Empty);
 431                                 writer.WriteElementString ("link", String.Empty, String.Empty);
 432                                 writer.WriteEndElement ();
 433                         }
 434                         if (Feed.Language != null)
 435                                 writer.WriteElementString ("language", String.Empty, Feed.Language);
 436
 437                         foreach (SyndicationPerson author in Feed.Authors)
 438                                 if (author != null) {
 439                                         writer.WriteStartElement ("managingEditor");
 440                                         WriteAttributeExtensions (writer, author, Version);
 441                                         writer.WriteString (author.Email);
 442                                         WriteElementExtensions (writer, author, Version);
 443                                         writer.WriteEndElement ();
 444                                 }
 445                         foreach (SyndicationCategory category in Feed.Categories)
 446                                 if (category != null) {
 447                                         writer.WriteStartElement ("category");
 448                                         if (category.Scheme != null)
 449                                                 writer.WriteAttributeString ("domain", category.Scheme);
 450                                         WriteAttributeExtensions (writer, category, Version);
 451                                         writer.WriteString (category.Name);
 452                                         WriteElementExtensions (writer, category, Version);
 453                                         writer.WriteEndElement ();
 454                                 }
 455
 456                         foreach (SyndicationLink link in Feed.Links)
 457                                 if (link != null) {
 458                                         writer.WriteStartElement ("link");
 459                                         WriteAttributeExtensions (writer, link, Version);
 460                                         writer.WriteString (link.Uri != null ? link.Uri.ToString () : String.Empty);
 461                                         WriteElementExtensions (writer, link, Version);
 462                                         writer.WriteEndElement ();
 463                                 }
 464
 465                         WriteItems (writer, Feed.Items, Feed.BaseUri);
 466
 467                         if (SerializeExtensionsAsAtom) {
 468
 469                                 if (Feed.Id != null) {
 470                                         writer.WriteStartElement ("a10", "id", AtomNamespace);
 471                                         writer.WriteString (Feed.Id);
 472                                         writer.WriteEndElement ();
 473                                 }
 474
 475                                 foreach (SyndicationPerson contributor in Feed.Contributors) {
 476                                         if (contributor != null) {
 477                                                 writer.WriteStartElement ("a10", "contributor", AtomNamespace);
 478                                                 WriteAttributeExtensions (writer, contributor, Version);
 479                                                 writer.WriteElementString ("a10", "name", AtomNamespace, contributor.Name);
 480                                                 writer.WriteElementString ("a10", "uri", AtomNamespace, contributor.Uri);
 481                                                 writer.WriteElementString ("a10", "email", AtomNamespace, contributor.Email);
 482                                                 WriteElementExtensions (writer, contributor, Version);
 483                                                 writer.WriteEndElement ();
 484                                         }
 485                                 }
 486                         }
 487
 488                         writer.WriteEndElement (); // </channel>
 489
 490                         if (writeRoot)
 491                                 writer.WriteEndElement (); // </rss>
 492                 }
 493
 494                 // FIXME: DateTimeOffset.ToString() needs another overload.
 495                 // When it is implemented, just remove ".DateTime" parts below.
 496                 string ToRFC822DateString (DateTimeOffset date)
 497                 {
 498                         switch (date.DateTime.Kind) {
 499                         case DateTimeKind.Utc:
 500                                 return date.DateTime.ToString ("ddd, dd MMM yyyy HH:mm:ss 'Z'", DateTimeFormatInfo.InvariantInfo);
 501                         case DateTimeKind.Local:
 502                                 StringBuilder sb = new StringBuilder (date.DateTime.ToString ("ddd, dd MMM yyyy HH:mm:ss zzz", DateTimeFormatInfo.InvariantInfo));
 503                                 sb.Remove (sb.Length - 3, 1);
 504                                 return sb.ToString (); // remove ':' from +hh:mm
 505                         default:
 506                                 return date.DateTime.ToString ("ddd, dd MMM yyyy HH:mm:ss", DateTimeFormatInfo.InvariantInfo);
 507                         }
 508                 }
 509         }
 510 }