/// <summary>
/// Loads this <see cref="MyCustomRssFeed"/> instance asynchronously using the specified <see cref="Uri"/>, <see cref="SyndicationResourceLoadSettings"/>, <see cref="ICredentials"/>, and <see cref="IWebProxy"/>.
/// </summary>
/// <param name="source">A <see cref="Uri"/> that represents the URL of the syndication resource XML data.</param>
/// <param name="settings">The <see cref="SyndicationResourceLoadSettings"/> object used to configure the <see cref="MyCustomRssFeed"/> instance. This value can be <b>null</b>.</param>
/// <param name="options">A <see cref="WebRequestOptions"/> that holds options that should be applied to web requests.</param>
/// <param name="userToken">A user-defined object that is passed to the method invoked when the asynchronous operation completes.</param>
/// <remarks>
/// <para>
/// To receive notification when the operation has completed or the operation has been canceled, add an event handler to the <see cref="Loaded"/> event.
/// You can cancel a <see cref="LoadAsync(Uri, SyndicationResourceLoadSettings, ICredentials, IWebProxy, Object)"/> operation by calling the <see cref="LoadAsyncCancel()"/> method.
/// </para>
/// <para>
/// After calling <see cref="LoadAsync(Uri, SyndicationResourceLoadSettings, ICredentials, IWebProxy, Object)"/>,
/// you must wait for the load operation to complete before attempting to load the syndication resource using the <see cref="LoadAsync(Uri, Object)"/> method.
/// </para>
/// </remarks>
/// <exception cref="ArgumentNullException">The <paramref name="source"/> is a null reference (Nothing in Visual Basic).</exception>
/// <exception cref="FormatException">The <paramref name="source"/> data does not conform to the expected syndication content format. In this case, the feed remains empty.</exception>
/// <exception cref="InvalidOperationException">This <see cref="MyCustomRssFeed"/> has a <see cref="LoadAsync(Uri, SyndicationResourceLoadSettings, ICredentials, IWebProxy, Object)"/> call in progress.</exception>
public void LoadAsync(Uri source, SyndicationResourceLoadSettings settings, WebRequestOptions options, Object userToken)
{
Guard.ArgumentNotNull(source, "source");
if (settings == null)
{
settings = new SyndicationResourceLoadSettings();
}
if (this.LoadOperationInProgress)
{
throw new InvalidOperationException();
}
this.LoadOperationInProgress = true;
this.AsyncLoadHasBeenCancelled = false;
asyncHttpWebRequest = SyndicationEncodingUtility.CreateWebRequest(source, options);
asyncHttpWebRequest.Timeout = Convert.ToInt32(settings.Timeout.TotalMilliseconds, System.Globalization.NumberFormatInfo.InvariantInfo);
object[] state = new object[6] {
asyncHttpWebRequest, this, source, settings, options, userToken
};
IAsyncResult result = asyncHttpWebRequest.BeginGetResponse(new AsyncCallback(AsyncLoadCallback), state);
ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, new WaitOrTimerCallback(AsyncTimeoutCallback), state, settings.Timeout, true);
}
/// <summary>
/// Called when a corresponding asynchronous load operation completes.
/// </summary>
/// <param name="result">The result of the asynchronous operation.</param>
private static void AsyncLoadCallback(IAsyncResult result)
{
System.Text.Encoding encoding = System.Text.Encoding.UTF8;
XPathNavigator navigator = null;
WebRequest httpWebRequest = null;
MyCustomRssFeed feed = null;
Uri source = null;
WebRequestOptions options = null;
SyndicationResourceLoadSettings settings = null;
if (result.IsCompleted)
{
object[] parameters = (object[])result.AsyncState;
httpWebRequest = parameters[0] as WebRequest;
feed = parameters[1] as MyCustomRssFeed;
source = parameters[2] as Uri;
settings = parameters[3] as SyndicationResourceLoadSettings;
options = parameters[4] as WebRequestOptions;
object userToken = parameters[5];
if (feed != null)
{
WebResponse httpWebResponse = (WebResponse)httpWebRequest.EndGetResponse(result);
using (Stream stream = httpWebResponse.GetResponseStream())
{
if (settings != null)
{
encoding = settings.CharacterEncoding;
}
using (StreamReader streamReader = new StreamReader(stream, encoding))
{
XmlReaderSettings readerSettings = new XmlReaderSettings();
readerSettings.IgnoreComments = true;
readerSettings.IgnoreWhitespace = true;
readerSettings.DtdProcessing = DtdProcessing.Ignore;
using (XmlReader reader = XmlReader.Create(streamReader, readerSettings))
{
if (encoding == System.Text.Encoding.UTF8)
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, null);
}
else
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, settings.CharacterEncoding);
}
// Code to load the syndication resource using the XPathNavigator would go here.
// If you support legacy formats, you would use a SyndicationResourceAdapter to fill the feed;
// otherwise you would utilize the feed's Load method.
feed.OnFeedLoaded(new SyndicationResourceLoadedEventArgs(navigator, source, options, userToken));
}
}
}
feed.LoadOperationInProgress = false;
}
}
}
/// <summary>
/// Loads the syndication resource from the specified <see cref="Stream"/>.
/// </summary>
/// <param name="stream">The <b>Stream</b> used to load the syndication resource.</param>
/// <param name="settings">The <see cref="SyndicationResourceLoadSettings"/> object used to configure the <see cref="MyCustomRssFeed"/> instance. This value can be <b>null</b>.</param>
/// <remarks>
/// After the load operation has successfully completed, the <see cref="MyCustomRssFeed.Loaded"/> event will be raised.
/// </remarks>
/// <exception cref="ArgumentNullException">The <paramref name="stream"/> is a null reference (Nothing in Visual Basic).</exception>
/// <exception cref="FormatException">The <paramref name="stream"/> data does not conform to the expected syndication content format. In this case, the feed remains empty.</exception>
/// <exception cref="XmlException">There is a load or parse error in the XML. In this case, the feed remains empty.</exception>
public void Load(Stream stream, SyndicationResourceLoadSettings settings)
{
Guard.ArgumentNotNull(stream, "stream");
if (settings != null)
{
this.Load(SyndicationEncodingUtility.CreateSafeNavigator(stream, settings.CharacterEncoding), settings);
}
else
{
this.Load(SyndicationEncodingUtility.CreateSafeNavigator(stream), settings);
}
}
/// <summary>
/// Loads this <see cref="AtomEntry"/> instance asynchronously using the specified <see cref="Uri"/>, <see cref="SyndicationResourceLoadSettings"/>, <see cref="ICredentials"/>, and <see cref="IWebProxy"/>.
/// </summary>
/// <param name="source">A <see cref="Uri"/> that represents the URL of the syndication resource XML data.</param>
/// <param name="settings">The <see cref="SyndicationResourceLoadSettings"/> object used to configure the <see cref="AtomEntry"/> instance. This value can be <b>null</b>.</param>
/// <param name="options">A <see cref="WebRequestOptions"/> that holds options that should be applied to web requests.</param>
/// <param name="userToken">A user-defined object that is passed to the method invoked when the asynchronous operation completes.</param>
/// <remarks>
/// <para>
/// To receive notification when the operation has completed or the operation has been canceled, add an event handler to the <see cref="AtomEntry.Loaded"/> event.
/// You can cancel a <see cref="LoadAsync(Uri, SyndicationResourceLoadSettings, ICredentials, IWebProxy, Object)"/> operation by calling the <see cref="LoadAsyncCancel()"/> method.
/// </para>
/// <para>
/// After calling <see cref="LoadAsync(Uri, SyndicationResourceLoadSettings, ICredentials, IWebProxy, Object)"/>,
/// you must wait for the load operation to complete before attempting to load the syndication resource using the <see cref="AtomEntry.LoadAsync(Uri, Object)"/> method.
/// </para>
/// </remarks>
/// <exception cref="ArgumentNullException">The <paramref name="source"/> is a null reference (Nothing in Visual Basic).</exception>
/// <exception cref="FormatException">The <paramref name="source"/> data does not conform to the expected syndication content format. In this case, the feed remains empty.</exception>
/// <exception cref="InvalidOperationException">This <see cref="AtomEntry"/> has a <see cref="LoadAsync(Uri, SyndicationResourceLoadSettings, ICredentials, IWebProxy, Object)"/> call in progress.</exception>
public new void LoadAsync(Uri source, SyndicationResourceLoadSettings settings, WebRequestOptions options, Object userToken)
{
//------------------------------------------------------------
// Validate parameters
//------------------------------------------------------------
Guard.ArgumentNotNull(source, "source");
//------------------------------------------------------------
// Use default settings if none specified by the caller
//------------------------------------------------------------
if (settings == null)
{
settings = new SyndicationResourceLoadSettings();
}
//------------------------------------------------------------
// Validate syndication resource state
//------------------------------------------------------------
if (this.LoadOperationInProgress)
{
throw new InvalidOperationException();
}
//------------------------------------------------------------
// Indicate that a load operation is in progress
//------------------------------------------------------------
this.LoadOperationInProgress = true;
//------------------------------------------------------------
// Reset the asynchronous load operation cancelled indicator
//------------------------------------------------------------
this.AsyncLoadHasBeenCancelled = false;
//------------------------------------------------------------
// Build HTTP web request used to retrieve the syndication resource
//------------------------------------------------------------
asyncHttpWebRequest = SyndicationEncodingUtility.CreateWebRequest(source, options);
asyncHttpWebRequest.Timeout = Convert.ToInt32(settings.Timeout.TotalMilliseconds, System.Globalization.NumberFormatInfo.InvariantInfo);
//------------------------------------------------------------
// Get the async response to the web request
//------------------------------------------------------------
object[] state = new object[6] {
asyncHttpWebRequest, this, source, settings, options, userToken
};
IAsyncResult result = asyncHttpWebRequest.BeginGetResponse(new AsyncCallback(AsyncLoadCallback), state);
//------------------------------------------------------------
// Register the timeout callback
//------------------------------------------------------------
ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, new WaitOrTimerCallback(AsyncTimeoutCallback), state, settings.Timeout, true);
}
/// <summary>
/// Loads the syndication resource from the supplied <see cref="Uri"/> using the specified <see cref="ICredentials">credentials</see>, <see cref="IWebProxy">proxy</see> and <see cref="SyndicationResourceLoadSettings"/>.
/// </summary>
/// <param name="source">A <see cref="Uri"/> that points to the location of the web resource used to load the syndication resource.</param>
/// <param name="options">A <see cref="WebRequestOptions"/> that holds options that should be applied to web requests.</param>
/// <param name="settings">The <see cref="SyndicationResourceLoadSettings"/> object used to configure the <see cref="MyCustomRssFeed"/> instance. This value can be <b>null</b>.</param>
/// <remarks>
/// <para>
/// <list type="bullet">
/// <item>
/// <description>
/// If <paramref name="settings"/> has a <see cref="SyndicationResourceLoadSettings.CharacterEncoding">character encoding</see> of <see cref="System.Text.Encoding.UTF8"/>
/// the character encoding of the <paramref name="source"/> will be attempt to be determined automatically, otherwise the specified character encoding will be used.
/// If automatic detection fails, a character encoding of <see cref="System.Text.Encoding.UTF8"/> is used by default.
/// </description>
/// </item>
/// <item>
/// <description>
/// After the load operation has successfully completed, the <see cref="MyCustomRssFeed.Loaded"/> event will be raised.
/// </description>
/// </item>
/// </list>
/// </para>
/// </remarks>
/// <exception cref="ArgumentNullException">The <paramref name="source"/> is a null reference (Nothing in Visual Basic).</exception>
/// <exception cref="FormatException">The <paramref name="source"/> data does not conform to the expected syndication content format. In this case, the feed remains empty.</exception>
/// <exception cref="XmlException">There is a load or parse error in the XML. In this case, the feed remains empty.</exception>
public void Load(Uri source, WebRequestOptions options, SyndicationResourceLoadSettings settings)
{
XPathNavigator navigator = null;
Guard.ArgumentNotNull(source, "source");
if (settings == null)
{
settings = new SyndicationResourceLoadSettings();
}
if (settings.CharacterEncoding == System.Text.Encoding.UTF8)
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, null);
}
else
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, settings.CharacterEncoding);
}
this.Load(navigator, settings, new SyndicationResourceLoadedEventArgs(navigator, source, options));
}
//============================================================
// CALLBACK DELEGATE METHODS
//============================================================
#region AsyncLoadCallback(IAsyncResult result)
/// <summary>
/// Called when a corresponding asynchronous load operation completes.
/// </summary>
/// <param name="result">The result of the asynchronous operation.</param>
private static void AsyncLoadCallback(IAsyncResult result)
{
//------------------------------------------------------------
// Local members
//------------------------------------------------------------
System.Text.Encoding encoding = System.Text.Encoding.UTF8;
XPathNavigator navigator = null;
WebRequest httpWebRequest = null;
AtomEntryResource entry = null;
Uri source = null;
WebRequestOptions options = null;
SyndicationResourceLoadSettings settings = null;
//------------------------------------------------------------
// Determine if the async send operation completed
//------------------------------------------------------------
if (result.IsCompleted)
{
//------------------------------------------------------------
// Extract the send operations parameters from the user state
//------------------------------------------------------------
object[] parameters = (object[])result.AsyncState;
httpWebRequest = parameters[0] as WebRequest;
entry = parameters[1] as AtomEntryResource;
source = parameters[2] as Uri;
settings = parameters[3] as SyndicationResourceLoadSettings;
options = parameters[4] as WebRequestOptions;
object userToken = parameters[5];
//------------------------------------------------------------
// Verify expected parameters were found
//------------------------------------------------------------
if (entry != null)
{
//------------------------------------------------------------
// Get the response to the syndication resource request
//------------------------------------------------------------
WebResponse httpWebResponse = (WebResponse)httpWebRequest.EndGetResponse(result);
//------------------------------------------------------------
// Load syndication resource
//------------------------------------------------------------
using (Stream stream = httpWebResponse.GetResponseStream())
{
if (settings != null)
{
encoding = settings.CharacterEncoding;
}
using (StreamReader streamReader = new StreamReader(stream, encoding))
{
XmlReaderSettings readerSettings = new XmlReaderSettings();
readerSettings.IgnoreComments = true;
readerSettings.IgnoreWhitespace = true;
readerSettings.ProhibitDtd = false;
using (XmlReader reader = XmlReader.Create(streamReader, readerSettings))
{
if (encoding == System.Text.Encoding.UTF8)
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, null);
}
else
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, settings.CharacterEncoding);
}
//------------------------------------------------------------
// Load syndication resource using the framework adapters
//------------------------------------------------------------
SyndicationResourceAdapter adapter = new SyndicationResourceAdapter(navigator, settings);
adapter.Fill(entry, SyndicationContentFormat.Atom);
//------------------------------------------------------------
// Extract member resource information from extensions
//------------------------------------------------------------
AtomPublishingEditedSyndicationExtension editedExtension = entry.FindExtension(AtomPublishingEditedSyndicationExtension.MatchByType) as AtomPublishingEditedSyndicationExtension;
if (editedExtension != null)
{
entry.EditedOn = editedExtension.Context.EditedOn;
}
AtomPublishingControlSyndicationExtension controlExtension = entry.FindExtension(AtomPublishingControlSyndicationExtension.MatchByType) as AtomPublishingControlSyndicationExtension;
if (controlExtension != null)
{
entry.IsDraft = controlExtension.Context.IsDraft;
}
//------------------------------------------------------------
// Raise Loaded event to notify registered handlers of state change
//------------------------------------------------------------
entry.OnEntryLoaded(new SyndicationResourceLoadedEventArgs(navigator, source, options, userToken));
}
}
}
//------------------------------------------------------------
// Reset load operation in progress indicator
//------------------------------------------------------------
entry.LoadOperationInProgress = false;
}
}
}
/// <summary>
/// Called when a corresponding asynchronous load operation completes.
/// </summary>
/// <param name="result">The result of the asynchronous operation.</param>
private static void AsyncLoadCallback(IAsyncResult result)
{
System.Text.Encoding encoding = System.Text.Encoding.UTF8;
XPathNavigator navigator = null;
WebRequest httpWebRequest = null;
AtomEntryResource entry = null;
Uri source = null;
WebRequestOptions options = null;
SyndicationResourceLoadSettings settings = null;
if (result.IsCompleted)
{
object[] parameters = (object[])result.AsyncState;
httpWebRequest = parameters[0] as WebRequest;
entry = parameters[1] as AtomEntryResource;
source = parameters[2] as Uri;
settings = parameters[3] as SyndicationResourceLoadSettings;
options = parameters[4] as WebRequestOptions;
object userToken = parameters[5];
if (entry != null)
{
WebResponse httpWebResponse = (WebResponse)httpWebRequest.EndGetResponse(result);
using (Stream stream = httpWebResponse.GetResponseStream())
{
if (settings != null)
{
encoding = settings.CharacterEncoding;
}
using (StreamReader streamReader = new StreamReader(stream, encoding))
{
XmlReaderSettings readerSettings = new XmlReaderSettings();
readerSettings.IgnoreComments = true;
readerSettings.IgnoreWhitespace = true;
readerSettings.DtdProcessing = DtdProcessing.Ignore;
using (XmlReader reader = XmlReader.Create(streamReader, readerSettings))
{
if (encoding == System.Text.Encoding.UTF8)
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, null);
}
else
{
navigator = SyndicationEncodingUtility.CreateSafeNavigator(source, options, settings.CharacterEncoding);
}
SyndicationResourceAdapter adapter = new SyndicationResourceAdapter(navigator, settings);
adapter.Fill(entry, SyndicationContentFormat.Atom);
AtomPublishingEditedSyndicationExtension editedExtension = entry.FindExtension(AtomPublishingEditedSyndicationExtension.MatchByType) as AtomPublishingEditedSyndicationExtension;
if (editedExtension != null)
{
entry.EditedOn = editedExtension.Context.EditedOn;
}
AtomPublishingControlSyndicationExtension controlExtension = entry.FindExtension(AtomPublishingControlSyndicationExtension.MatchByType) as AtomPublishingControlSyndicationExtension;
if (controlExtension != null)
{
entry.IsDraft = controlExtension.Context.IsDraft;
}
entry.OnEntryLoaded(new SyndicationResourceLoadedEventArgs(navigator, source, options, userToken));
}
}
}
entry.LoadOperationInProgress = false;
}
}
}
