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/* RssReader.cs
* ============
*
* RSS.NET (http://rss-net.sf.net/)
* Copyright � 2002, 2003 George Tsiokos. All Rights Reserved.
*
* RSS 2.0 (http://blogs.law.harvard.edu/tech/rss)
* RSS 2.0 is offered by the Berkman Center for Internet & Society at
* Harvard Law School under the terms of the Attribution/Share Alike
* Creative Commons license.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
using System;
using System.Collections;
using System.Xml;
using System.Text;
using System.IO;
namespace Rss
{
/// <summary>Reads an RSS file.</summary>
/// <remarks>Provides fast, non-cached, forward-only access to RSS data.</remarks>
public class RssReader
{
// TODO: Add support for modules
private Stack xmlNodeStack = new Stack();
private StringBuilder elementText = new StringBuilder();
private XmlTextReader reader = null;
private bool wroteChannel = false;
private RssVersion rssVersion = RssVersion.Empty;
private ExceptionCollection exceptions = new ExceptionCollection();
private RssTextInput textInput = null;
private RssImage image = null;
private RssCloud cloud = null;
private RssChannel channel = null;
private RssSource source = null;
private RssEnclosure enclosure = null;
private RssGuid guid = null;
private RssCategory category = null;
private RssItem item = null;
private void InitReader()
{
reader.WhitespaceHandling = WhitespaceHandling.None;
reader.XmlResolver = null;
}
#region Constructors
/// <summary>Initializes a new instance of the RssReader class with the specified URL or filename.</summary>
/// <param name="url">The URL or filename for the file containing the RSS data.</param>
/// <exception cref="ArgumentException">Occures when unable to retrieve file containing the RSS data.</exception>
public RssReader(string url)
{
try
{
reader = new XmlTextReader(url);
InitReader();
}
catch (Exception e)
{
throw new ArgumentException("Unable to retrieve file containing the RSS data.", e);
}
}
/// <summary>Creates an instance of the RssReader class using the specified TextReader.</summary>
/// <param name="textReader">specified TextReader</param>
/// <exception cref="ArgumentException">Occures when unable to retrieve file containing the RSS data.</exception>
public RssReader(TextReader textReader)
{
try
{
reader = new XmlTextReader(textReader);
InitReader();
}
catch (Exception e)
{
throw new ArgumentException("Unable to retrieve file containing the RSS data.", e);
}
}
/// <summary>Creates an instance of the RssReader class using the specified Stream.</summary>
/// <exception cref="ArgumentException">Occures when unable to retrieve file containing the RSS data.</exception>
/// <param name="stream">Stream to read from</param>
public RssReader(Stream stream)
{
try
{
reader = new XmlTextReader(stream);
InitReader();
}
catch (Exception e)
{
throw new ArgumentException("Unable to retrieve file containing the RSS data.", e);
}
}
#endregion
/// <summary>Reads the next RssElement from the stream.</summary>
/// <returns>An RSS Element</returns>
/// <exception cref="InvalidOperationException">RssReader has been closed, and can not be read.</exception>
/// <exception cref="System.IO.FileNotFoundException">RSS file not found.</exception>
/// <exception cref="System.Xml.XmlException">Invalid XML syntax in RSS file.</exception>
/// <exception cref="System.IO.EndOfStreamException">Unable to read an RssElement. Reached the end of the stream.</exception>
public RssElement Read()
{
bool readData = false;
bool pushElement = true;
RssElement rssElement = null;
int lineNumber = -1;
int linePosition = -1;
if (reader == null)
throw new InvalidOperationException("RssReader has been closed, and can not be read.");
do
{
pushElement = true;
try
{
readData = reader.Read();
}
catch (System.IO.EndOfStreamException e)
{
throw new System.IO.EndOfStreamException("Unable to read an RssElement. Reached the end of the stream.", e);
}
catch (System.Xml.XmlException e)
{
if (lineNumber != -1 || linePosition != -1)
if (reader.LineNumber == lineNumber && reader.LinePosition == linePosition)
throw exceptions.LastException;
lineNumber = reader.LineNumber;
linePosition = reader.LinePosition;
exceptions.Add(e); // just add to list of exceptions and continue :)
}
if (readData)
{
string readerName = reader.Name.ToLower();
switch (reader.NodeType)
{
case XmlNodeType.Element:
{
if (reader.IsEmptyElement)
break;
elementText = new StringBuilder();
switch (readerName)
{
case "item":
// is this the end of the channel element? (absence of </channel> before <item>)
if (!wroteChannel)
{
wroteChannel = true;
rssElement = channel; // return RssChannel
readData = false;
}
item = new RssItem(); // create new RssItem
channel.Items.Add(item);
break;
case "source":
source = new RssSource();
item.Source = source;
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
switch (reader.Name.ToLower())
{
case "url":
try
{
source.Url = new Uri(reader.Value);
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
}
}
break;
case "enclosure":
enclosure = new RssEnclosure();
item.Enclosure = enclosure;
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
switch (reader.Name.ToLower())
{
case "url":
try
{
enclosure.Url = new Uri(reader.Value);
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "length":
try
{
enclosure.Length = int.Parse(reader.Value);
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "type":
enclosure.Type = reader.Value;
break;
}
}
break;
case "guid":
guid = new RssGuid();
item.Guid = guid;
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
switch (reader.Name.ToLower())
{
case "ispermalink":
try
{
guid.PermaLink = bool.Parse(reader.Value);
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
}
}
break;
case "category":
category = new RssCategory();
if ((string)xmlNodeStack.Peek() == "channel")
channel.Categories.Add(category);
else
item.Categories.Add(category);
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
switch (reader.Name.ToLower())
{
case "url":
goto case "domain";
case "domain":
category.Domain = reader.Value;
break;
}
}
break;
case "channel":
channel = new RssChannel();
textInput = null;
image = null;
cloud = null;
source = null;
enclosure = null;
category = null;
item = null;
break;
case "image":
image = new RssImage();
channel.Image = image;
break;
case "textinput":
textInput = new RssTextInput();
channel.TextInput = textInput;
break;
case "cloud":
pushElement = false;
cloud = new RssCloud();
channel.Cloud = cloud;
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
switch (reader.Name.ToLower())
{
case "domain":
cloud.Domain = reader.Value;
break;
case "port":
try
{
cloud.Port = ushort.Parse(reader.Value);
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "path":
cloud.Path = reader.Value;
break;
case "registerprocedure":
cloud.RegisterProcedure = reader.Value;
break;
case "protocol":
switch (reader.Value.ToLower())
{
case "xml-rpc":
cloud.Protocol = RssCloudProtocol.XmlRpc;
break;
case "soap":
cloud.Protocol = RssCloudProtocol.Soap;
break;
case "http-post":
cloud.Protocol = RssCloudProtocol.HttpPost;
break;
default:
cloud.Protocol = RssCloudProtocol.Empty;
break;
}
break;
}
}
break;
case "rss":
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
if (reader.Name.ToLower() == "version")
switch (reader.Value)
{
case "0.91":
rssVersion = RssVersion.RSS091;
break;
case "0.92":
rssVersion = RssVersion.RSS092;
break;
case "2.0":
rssVersion = RssVersion.RSS20;
break;
default:
rssVersion = RssVersion.NotSupported;
break;
}
}
break;
case "rdf":
for (int i=0; i < reader.AttributeCount; i++)
{
reader.MoveToAttribute(i);
if (reader.Name.ToLower() == "version")
switch (reader.Value)
{
case "0.90":
rssVersion = RssVersion.RSS090;
break;
case "1.0":
rssVersion = RssVersion.RSS10;
break;
default:
rssVersion = RssVersion.NotSupported;
break;
}
}
break;
}
if (pushElement)
xmlNodeStack.Push(readerName);
break;
}
case XmlNodeType.EndElement:
{
if (xmlNodeStack.Count == 1)
break;
string childElementName = (string)xmlNodeStack.Pop();
string parentElementName = (string)xmlNodeStack.Peek();
switch (childElementName) // current element
{
// item classes
case "item":
rssElement = item;
readData = false;
break;
case "source":
source.Name = elementText.ToString();
rssElement = source;
readData = false;
break;
case "enclosure":
rssElement = enclosure;
readData = false;
break;
case "guid":
guid.Name = elementText.ToString();
rssElement = guid;
readData = false;
break;
case "category": // parent is either item or channel
category.Name = elementText.ToString();
rssElement = category;
readData = false;
break;
// channel classes
case "channel":
if (wroteChannel)
wroteChannel = false;
else
{
wroteChannel = true;
rssElement = channel;
readData = false;
}
break;
case "textinput":
rssElement = textInput;
readData = false;
break;
case "image":
rssElement = image;
readData = false;
break;
case "cloud":
rssElement = cloud;
readData = false;
break;
}
switch (parentElementName) // parent element
{
case "item":
switch (childElementName)
{
case "title":
item.Title = elementText.ToString();
break;
case "link":
item.Link = new Uri(elementText.ToString());
break;
case "description":
item.Description = elementText.ToString();
break;
case "content:encoded":
item.Content = elementText.ToString ();
break;
case "author":
item.Author = elementText.ToString();
break;
case "comments":
item.Comments = elementText.ToString();
break;
case "pubdate":
try
{
item.PubDate = DateTime.Parse(elementText.ToString());
}
catch (Exception e)
{
try {
string tmp = elementText.ToString ();
tmp = tmp.Substring (0, tmp.Length - 5);
if (!tmp.EndsWith("GMT"))
tmp += "GMT";
item.PubDate = DateTime.Parse (tmp);
}
catch
{
exceptions.Add(e);
}
}
break;
}
break;
case "channel":
switch (childElementName)
{
case "title":
channel.Title = elementText.ToString();
break;
case "link":
try
{
channel.Link = new Uri(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "description":
channel.Description = elementText.ToString();
break;
case "language":
channel.Language = elementText.ToString();
break;
case "copyright":
channel.Copyright = elementText.ToString();
break;
case "managingeditor":
channel.ManagingEditor = elementText.ToString();
break;
case "webmaster":
channel.WebMaster = elementText.ToString();
break;
case "rating":
channel.Rating = elementText.ToString();
break;
case "pubdate":
try
{
channel.PubDate = DateTime.Parse(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "lastbuilddate":
try
{
channel.LastBuildDate = DateTime.Parse(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "generator":
channel.Generator = elementText.ToString();
break;
case "docs":
channel.Docs = elementText.ToString();
break;
case "ttl":
try
{
channel.TimeToLive = int.Parse(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
}
break;
case "image":
switch (childElementName)
{
case "url":
try
{
image.Url = new Uri(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "title":
image.Title = elementText.ToString();
break;
case "link":
try
{
image.Link = new Uri(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "description":
image.Description = elementText.ToString();
break;
case "width":
try
{
image.Width = Byte.Parse(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
case "height":
try
{
image.Height = Byte.Parse(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
}
break;
case "textinput":
switch (childElementName)
{
case "title":
textInput.Title = elementText.ToString();
break;
case "description":
textInput.Description = elementText.ToString();
break;
case "name":
textInput.Name = elementText.ToString();
break;
case "link":
try
{
textInput.Link = new Uri(elementText.ToString());
}
catch (Exception e)
{
exceptions.Add(e);
}
break;
}
break;
case "skipdays":
if (childElementName == "day")
switch (elementText.ToString().ToLower())
{
case "monday":
channel.SkipDays[0] = true;
break;
case "tuesday":
channel.SkipDays[1] = true;
break;
case "wednesday":
channel.SkipDays[2] = true;
break;
case "thursday":
channel.SkipDays[3] = true;
break;
case "friday":
channel.SkipDays[4] = true;
break;
case "saturday":
channel.SkipDays[5] = true;
break;
case "sunday":
channel.SkipDays[6] = true;
break;
}
break;
case "skiphours":
if (childElementName == "hour")
channel.SkipHours[Byte.Parse(elementText.ToString().ToLower())] = true;
break;
}
break;
}
case XmlNodeType.Text:
elementText.Append(reader.Value);
break;
case XmlNodeType.CDATA:
elementText.Append(reader.Value);
break;
}
}
}
while (readData);
return rssElement;
}
/// <summary>A collection of all exceptions the RssReader class has encountered.</summary>
public ExceptionCollection Exceptions
{
get { return exceptions; }
}
/// <summary>Gets the RSS version of the stream.</summary>
/// <value>One of the <see cref="RssVersion"/> values.</value>
public RssVersion Version
{
get { return rssVersion; }
}
/// <summary>Closes connection to file.</summary>
/// <remarks>This method also releases any resources held while reading.</remarks>
public void Close()
{
textInput = null;
image = null;
cloud = null;
channel = null;
source = null;
enclosure = null;
category = null;
item = null;
if (reader!=null)
{
reader.Close();
reader = null;
}
elementText = null;
xmlNodeStack = null;
}
}
}
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