internal object Lookup(string lookupKey) {
if (lookupKey==null) {
return null;
}
object mostSpecificMatch = null;
int longestMatchPrefix = 0;
int prefixLen;
lock (m_Store) {
//
// readers don't need to be locked, but we lock() because:
// "The enumerator does not have exclusive access to the collection.
//
// When an enumerator is instantiated, it takes a snapshot of the current state
// of the collection. If changes are made to the collection, such as adding,
// modifying or deleting elements, the snapshot gets out of sync and the
// enumerator throws an InvalidOperationException. Two enumerators instantiated
// from the same collection at the same time can have different snapshots of the
// collection."
//
// enumerate through every credential in the cache
//
string prefix;
foreach (DictionaryEntry entry in m_Store) {
prefix = (string)entry.Key;
if (lookupKey.StartsWith(prefix)) {
prefixLen = prefix.Length;
//
// check if the match is better than the current-most-specific match
//
if (prefixLen>longestMatchPrefix) {
//
// Yes-- update the information about currently preferred match
//
longestMatchPrefix = prefixLen;
mostSpecificMatch = entry.Value;
}
}
}
}
return mostSpecificMatch;
}
/// <devdoc>
/// <para>Pre-authenticates a request.</para>
/// </devdoc>
public static Authorization PreAuthenticate(WebRequest request, ICredentials credentials)
{
GlobalLog.Print("AuthenticationManager::PreAuthenticate() request:" + ValidationHelper.HashString(request) + " credentials:" + ValidationHelper.HashString(credentials));
if (request == null)
{
throw new ArgumentNullException("request");
}
if (credentials == null)
{
return(null);
}
HttpWebRequest httpWebRequest = request as HttpWebRequest;
IAuthenticationModule authenticationModule;
if (httpWebRequest == null)
{
return(null);
}
//
// PrefixLookup is thread-safe
//
string moduleName = s_ModuleBinding.Lookup(httpWebRequest.ChallengedUri.AbsoluteUri) as string;
GlobalLog.Print("AuthenticationManager::PreAuthenticate() s_ModuleBinding.Lookup returns:" + ValidationHelper.ToString(moduleName));
if (moduleName == null)
{
return(null);
}
authenticationModule = findModule(moduleName);
if (authenticationModule == null)
{
// The module could have been unregistered
// No preauthentication is possible
return(null);
}
// Otherwise invoke the PreAuthenticate method
// we're guaranteed that CanPreAuthenticate is true because we check before calling BindModule()
Authorization authorization = authenticationModule.PreAuthenticate(request, credentials);
if (authorization != null && !authorization.Complete && httpWebRequest != null)
{
httpWebRequest.CurrentAuthenticationState.Module = authenticationModule;
}
GlobalLog.Print("AuthenticationManager::PreAuthenticate() IAuthenticationModule.PreAuthenticate() returned authorization:" + ValidationHelper.HashString(authorization));
return(authorization);
}
