1 files changed, 122 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.AspNet/Clients/OAuth2/OAuth2Client.cs b/src/DotNetOpenAuth.AspNet/Clients/OAuth2/OAuth2Client.cs
new file mode 100644
index 0000000..ff50521
--- /dev/null
+++ b/src/DotNetOpenAuth.AspNet/Clients/OAuth2/OAuth2Client.cs
@@ -0,0 +1,122 @@
+namespace DotNetOpenAuth.AspNet.Clients {
+	using System;
+	using System.Collections.Generic;
+	using System.Diagnostics.CodeAnalysis;
+	using System.Web;
+
+	/// <summary>
+	/// Represents the base class for OAuth 2.0 clients
+	/// </summary>
+	public abstract class OAuth2Client : IAuthenticationClient {
+		private readonly string _providerName;
+		private Uri _returnUrl;
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="OAuth2Client"/> class with the specified provider name.
+		/// </summary>
+		/// <param name="providerName">Name of the provider.</param>
+		protected OAuth2Client(string providerName) {
+			if (providerName == null) {
+				throw new ArgumentNullException("providerName");
+			}
+
+			_providerName = providerName;
+		}
+
+		/// <summary>
+		/// Gets the name of the provider which provides authentication service.
+		/// </summary>
+		public string ProviderName {
+			get { return _providerName; }
+		}
+
+		/// <summary>
+		/// Attempts to authenticate users by forwarding them to an external website, and
+		/// upon succcess or failure, redirect users back to the specified url.
+		/// </summary>
+		/// <param name="returnUrl">The return url after users have completed authenticating against external website.</param>
+		public virtual void RequestAuthentication(HttpContextBase context, Uri returnUrl) {
+			if (context == null) {
+				throw new ArgumentNullException("context");
+			}
+
+			if (returnUrl == null) {
+				throw new ArgumentNullException("returnUrl");
+			}
+
+			_returnUrl = returnUrl;
+
+			string redirectUrl = GetServiceLoginUrl(returnUrl).ToString();
+			context.Response.Redirect(redirectUrl, endResponse: true);
+		}
+
+		/// <summary>
+		/// Check if authentication succeeded after user is redirected back from the service provider.
+		/// </summary>
+		/// <returns>
+		/// An instance of <see cref="AuthenticationResult"/> containing authentication result.
+		/// </returns>
+		public virtual AuthenticationResult VerifyAuthentication(HttpContextBase context) {
+			if (context == null) {
+				throw new ArgumentNullException("context");
+			}
+
+			string code = context.Request.QueryString["code"];
+			if (String.IsNullOrEmpty(code)) {
+				return AuthenticationResult.Failed;
+			}
+
+			string accessToken = QueryAccessToken(_returnUrl, code);
+			if (accessToken == null) {
+				return AuthenticationResult.Failed;
+			}
+
+			IDictionary<string, string> userData = GetUserData(accessToken);
+			if (userData == null) {
+				return AuthenticationResult.Failed;
+			}
+			string id = userData["id"];
+			string name;
+			// Some oAuth providers do not return value for the 'username' attribute. 
+			// In that case, try the 'name' attribute. If it's still unavailable, fall back to 'id'
+			if (!userData.TryGetValue("username", out name) && !userData.TryGetValue("name", out name)) {
+				name = id;
+			}
+
+			// add the access token to the user data dictionary just in case page developers want to use it
+			userData["accesstoken"] = accessToken;
+
+			return new AuthenticationResult(
+				isSuccessful: true,
+				provider: ProviderName,
+				providerUserId: id,
+				userName: name,
+				extraData: userData);
+		}
+
+		/// <summary>
+		/// Gets the full url pointing to the login page for this client. The url should include the 
+		/// specified return url so that when the login completes, user is redirected back to that url.
+		/// </summary>
+		/// <param name="returnUrl">The return URL.</param>
+		/// <returns></returns>
+		[SuppressMessage("Microsoft.Naming", "CA1726:UsePreferredTerms", MessageId = "Login", Justification = "Login is used more consistently in ASP.Net")]
+		protected abstract Uri GetServiceLoginUrl(Uri returnUrl);
+
+		/// <summary>
+		/// Queries the access token from the specified authorization code.
+		/// </summary>
+		/// <param name="returnUrl">The return URL.</param>
+		/// <param name="authorizationCode">The authorization code.</param>
+		/// <returns></returns>
+		protected abstract string QueryAccessToken(Uri returnUrl, string authorizationCode);
+
+		/// <summary>
+		/// Given the access token, gets the logged-in user's data. The returned dictionary must include
+		/// two keys 'id', and 'username'.
+		/// </summary>
+		/// <param name="accessToken">The access token of the current user.</param>
+		/// <returns>A dictionary contains key-value pairs of user data</returns>
+		protected abstract IDictionary<string, string> GetUserData(string accessToken);
+	}
+}
+\ No newline at end of file