/// <summary>
/// Searches for an XRDS document at the realm URL, and if found, searches
/// for a description of a relying party endpoints (OpenId login pages).
/// </summary>
/// <param name="requestHandler">The mechanism to use for sending HTTP requests.</param>
/// <param name="allowRedirects">Whether redirects may be followed when discovering the Realm.
/// This may be true when creating an unsolicited assertion, but must be
/// false when performing return URL verification per 2.0 spec section 9.2.1.</param>
/// <returns>
/// The details of the endpoints if found; or <c>null</c> if no service document was discovered.
/// </returns>
internal virtual IEnumerable<RelyingPartyEndpointDescription> Discover(IDirectWebRequestHandler requestHandler, bool allowRedirects)
{
// Attempt YADIS discovery
DiscoveryResult yadisResult = Yadis.Discover(requestHandler, this.UriWithWildcardChangedToWww, false);
if (yadisResult != null) {
// Detect disallowed redirects, since realm discovery never allows them for security.
ErrorUtilities.VerifyProtocol(allowRedirects || yadisResult.NormalizedUri == yadisResult.RequestUri, OpenIdStrings.RealmCausedRedirectUponDiscovery, yadisResult.RequestUri);
if (yadisResult.IsXrds) {
try {
XrdsDocument xrds = new XrdsDocument(yadisResult.ResponseText);
return xrds.FindRelyingPartyReceivingEndpoints();
} catch (XmlException ex) {
throw ErrorUtilities.Wrap(ex, XrdsStrings.InvalidXRDSDocument);
}
}
}
return null;
}
