//============================================================
// ICOMPARABLE IMPLEMENTATION
//============================================================
#region CompareTo(object obj)
/// <summary>
/// Compares the current instance with another object of the same type.
/// </summary>
/// <param name="obj">An object to compare with this instance.</param>
/// <returns>A 32-bit signed integer that indicates the relative order of the objects being compared.</returns>
/// <exception cref="ArgumentException">The <paramref name="obj"/> is not the expected <see cref="Type"/>.</exception>
public int CompareTo(object obj)
{
//------------------------------------------------------------
// If target is a null reference, instance is greater
//------------------------------------------------------------
if (obj == null)
{
return(1);
}
//------------------------------------------------------------
// Determine comparison result using property state of objects
//------------------------------------------------------------
DiscoverableSyndicationEndpoint value = obj as DiscoverableSyndicationEndpoint;
if (value != null)
{
int result = String.Compare(this.ContentType, value.ContentType, StringComparison.OrdinalIgnoreCase);
result = result | Uri.Compare(this.Source, value.Source, UriComponents.AbsoluteUri, UriFormat.SafeUnescaped, StringComparison.OrdinalIgnoreCase);
result = result | String.Compare(this.Title, value.Title, StringComparison.OrdinalIgnoreCase);
return(result);
}
else
{
throw new ArgumentException(String.Format(null, "obj is not of type {0}, type was found to be '{1}'.", this.GetType().FullName, obj.GetType().FullName), "obj");
}
}
/// <summary>
/// Compares the current instance with another object of the same type.
/// </summary>
/// <param name="obj">An object to compare with this instance.</param>
/// <returns>A 32-bit signed integer that indicates the relative order of the objects being compared.</returns>
/// <exception cref="ArgumentException">The <paramref name="obj"/> is not the expected <see cref="Type"/>.</exception>
public int CompareTo(object obj)
{
if (obj == null)
{
return(1);
}
DiscoverableSyndicationEndpoint value = obj as DiscoverableSyndicationEndpoint;
if (value != null)
{
int result = String.Compare(this.ContentType, value.ContentType, StringComparison.OrdinalIgnoreCase);
result = result | Uri.Compare(this.Source, value.Source, UriComponents.AbsoluteUri, UriFormat.SafeUnescaped, StringComparison.OrdinalIgnoreCase);
result = result | String.Compare(this.Title, value.Title, StringComparison.OrdinalIgnoreCase);
return(result);
}
else
{
throw new ArgumentException(String.Format(null, "obj is not of type {0}, type was found to be '{1}'.", this.GetType().FullName, obj.GetType().FullName), "obj");
}
}
/// <summary>
/// Extracts auto-discoverable syndication endpoints from the supplied HTML markup.
/// </summary>
/// <param name="content">The HTML markup to parse.</param>
/// <returns>
/// A collection of <see cref="DiscoverableSyndicationEndpoint"/> objects that represent auto-discoverable syndicated content endpoints contained within the <paramref name="content"/>.
/// </returns>
/// <remarks>
/// See <a href="http://www.rssboard.org/rss-autodiscovery">http://www.rssboard.org/rss-autodiscovery</a> for
/// further information about the auto-discovery of syndicated content.
/// </remarks>
/// <exception cref="ArgumentNullException">The <paramref name="content"/> is a null reference (Nothing in Visual Basic).</exception>
/// <exception cref="ArgumentNullException">The <paramref name="content"/> is an empty string.</exception>
public static Collection<DiscoverableSyndicationEndpoint> ExtractDiscoverableSyndicationEndpoints(string content)
{
//------------------------------------------------------------
// Local members
//------------------------------------------------------------
Collection<DiscoverableSyndicationEndpoint> results = new Collection<DiscoverableSyndicationEndpoint>();
Regex linkPattern = new Regex("<link[^>]+", RegexOptions.IgnoreCase);
//------------------------------------------------------------
// Validate parameter
//------------------------------------------------------------
Guard.ArgumentNotNullOrEmptyString(content, "content");
//------------------------------------------------------------
// Extract <link> elements using pattern matching
//------------------------------------------------------------
MatchCollection links = linkPattern.Matches(content);
foreach(Match link in links)
{
Hashtable linkAttributes = SyndicationDiscoveryUtility.ExtractHtmlAttributes(link.Value);
if (linkAttributes.ContainsKey("HREF") && linkAttributes.ContainsKey("REL") && linkAttributes.ContainsKey("TYPE"))
{
string href = (string)linkAttributes["HREF"];
string rel = (string)linkAttributes["REL"];
string type = (string)linkAttributes["TYPE"];
//------------------------------------------------------------
// Determine if the rel attribute indicates an alternate link
//------------------------------------------------------------
if (String.Compare(rel, "alternate", StringComparison.OrdinalIgnoreCase) == 0)
{
Uri url;
if (Uri.TryCreate(href, UriKind.RelativeOrAbsolute, out url))
{
//------------------------------------------------------------
// Create auto-discovery endpoint and add to results
//------------------------------------------------------------
DiscoverableSyndicationEndpoint endpoint = new DiscoverableSyndicationEndpoint();
endpoint.Source = url;
if (!String.IsNullOrEmpty(type))
{
endpoint.ContentType = type;
}
if (linkAttributes.ContainsKey("TITLE"))
{
string title = (string)linkAttributes["TITLE"];
if (!String.IsNullOrEmpty(title))
{
endpoint.Title = title;
}
}
results.Add(endpoint);
}
}
}
}
return results;
}
