Adds extensibility points for authenticating OAuth 2 clients at the client and authorization server ends.

Fixes #105
Related to #75

1 files changed, 50 insertions, 10 deletions

diff --git a/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ClientBase.cs b/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ClientBase.cs
index 77b9cc6..5f377ae 100644
--- a/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ClientBase.cs
+++ b/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ClientBase.cs
@@ -26,13 +26,16 @@ namespace DotNetOpenAuth.OAuth2 {
 		/// </summary>
 		/// <param name="authorizationServer">The token issuer.</param>
 		/// <param name="clientIdentifier">The client identifier.</param>
-		/// <param name="clientSecret">The client secret.</param>
-		protected ClientBase(AuthorizationServerDescription authorizationServer, string clientIdentifier = null, string clientSecret = null) {
+		/// <param name="clientCredentialApplicator">
+		/// The tool to use to apply client credentials to authenticated requests to the Authorization Server.  
+		/// May be <c>null</c> for clients with no secret or other means of authentication.
+		/// </param>
+		protected ClientBase(AuthorizationServerDescription authorizationServer, string clientIdentifier = null, ClientCredentialApplicator clientCredentialApplicator = null) {
 			Requires.NotNull(authorizationServer, "authorizationServer");
 			this.AuthorizationServer = authorizationServer;
 			this.Channel = new OAuth2ClientChannel();
 			this.ClientIdentifier = clientIdentifier;
-			this.ClientSecret = clientSecret;
+			this.ClientCredentialApplicator = clientCredentialApplicator;
 		}
 
 		/// <summary>
@@ -50,12 +53,26 @@ namespace DotNetOpenAuth.OAuth2 {
 		/// <summary>
 		/// Gets or sets the identifier by which this client is known to the Authorization Server.
 		/// </summary>
-		public string ClientIdentifier { get; set; }
+		public string ClientIdentifier {
+			get { return this.OAuthChannel.ClientIdentifier; }
+			set { this.OAuthChannel.ClientIdentifier = value; }
+		}
+
+		/// <summary>
+		/// Gets or sets the tool to use to apply client credentials to authenticated requests to the Authorization Server.
+		/// </summary>
+		/// <value>May be <c>null</c> if this client has no client secret.</value>
+		public ClientCredentialApplicator ClientCredentialApplicator {
+			get { return this.OAuthChannel.ClientCredentialApplicator; }
+			set { this.OAuthChannel.ClientCredentialApplicator = value; }
+		}
 
 		/// <summary>
-		/// Gets or sets the client secret shared with the Authorization Server.
+		/// Gets the OAuth client channel.
 		/// </summary>
-		public string ClientSecret { get; set; }
+		internal IOAuth2ChannelWithClient OAuthChannel {
+			get { return (IOAuth2ChannelWithClient)this.Channel; }
+		}
 
 		/// <summary>
 		/// Adds the necessary HTTP Authorization header to an HTTP request for protected resources
@@ -118,10 +135,11 @@ namespace DotNetOpenAuth.OAuth2 {
 
 			var request = new AccessTokenRefreshRequestC(this.AuthorizationServer) {
 				ClientIdentifier = this.ClientIdentifier,
-				ClientSecret = this.ClientSecret,
 				RefreshToken = authorization.RefreshToken,
 			};
 
+			this.ApplyClientCredential(request);
+
 			var response = this.Channel.Request<AccessTokenSuccessResponse>(request);
 			UpdateAuthorizationWithResponse(authorization, response);
 			return true;
@@ -145,10 +163,11 @@ namespace DotNetOpenAuth.OAuth2 {
 
 			var request = new AccessTokenRefreshRequestC(this.AuthorizationServer) {
 				ClientIdentifier = this.ClientIdentifier,
-				ClientSecret = this.ClientSecret,
 				RefreshToken = refreshToken,
 			};
 
+			this.ApplyClientCredential(request);
+
 			var response = this.Channel.Request<AccessTokenSuccessResponse>(request);
 			var authorization = new AuthorizationState();
 			UpdateAuthorizationWithResponse(authorization, response);
@@ -250,10 +269,10 @@ namespace DotNetOpenAuth.OAuth2 {
 
 			var accessTokenRequest = new AccessTokenAuthorizationCodeRequestC(this.AuthorizationServer) {
 				ClientIdentifier = this.ClientIdentifier,
-				ClientSecret = this.ClientSecret,
 				Callback = authorizationState.Callback,
 				AuthorizationCode = authorizationSuccess.AuthorizationCode,
 			};
+			this.ApplyClientCredential(accessTokenRequest);
 			IProtocolMessage accessTokenResponse = this.Channel.Request(accessTokenRequest);
 			var accessTokenSuccess = accessTokenResponse as AccessTokenSuccessResponse;
 			var failedAccessTokenResponse = accessTokenResponse as AccessTokenFailedResponse;
@@ -267,6 +286,27 @@ namespace DotNetOpenAuth.OAuth2 {
 		}
 
 		/// <summary>
+		/// Applies the default client authentication mechanism given a client secret.
+		/// </summary>
+		/// <param name="secret">The client secret.  May be <c>null</c></param>
+		/// <returns>The client credential applicator.</returns>
+		protected static ClientCredentialApplicator DefaultSecretApplicator(string secret) {
+			return secret == null ? ClientCredentialApplicator.NoSecret() : ClientCredentialApplicator.NetworkCredential(secret);
+		}
+
+		/// <summary>
+		/// Applies any applicable client credential to an authenticated outbound request to the authorization server.
+		/// </summary>
+		/// <param name="request">The request to apply authentication information to.</param>
+		protected void ApplyClientCredential(AuthenticatedClientRequestBase request) {
+			Requires.NotNull(request, "request");
+
+			if (this.ClientCredentialApplicator != null) {
+				this.ClientCredentialApplicator.ApplyClientCredential(this.ClientIdentifier, request);
+			}
+		}
+
+		/// <summary>
 		/// Calculates the fraction of life remaining in an access token.
 		/// </summary>
 		/// <param name="authorization">The authorization to measure.</param>
@@ -295,7 +335,7 @@ namespace DotNetOpenAuth.OAuth2 {
 			var authorizationState = new AuthorizationState(scopes);
 
 			request.ClientIdentifier = this.ClientIdentifier;
-			request.ClientSecret = this.ClientSecret;
+			this.ApplyClientCredential(request);
 			request.Scope.UnionWith(authorizationState.Scope);
 
 			var response = this.Channel.Request(request);