[#816] OAuth2 error handling

documentation/manual/libs.textile

@@ -190,11 +190,14 @@ To connect to a service, you need the create a OAuth2 instance using the followi
 bc. public static void auth() {
     // FACEBOOK is a OAuth2 object
     if (OAuth2.isCodeResponse()) {
-        String access_token = FACEBOOK.getAccessToken();
-        // Save access_token, you will need it to request the service
+        OAuth2.Response response = FACEBOOK.retrieveAccessToken(authUrl); // authUrl must be the same as the retrieveVerificationCode call
+        String accessToken = response.accessToken; // null if an error occurred
+        OAuth2.Error = response.error; // null if the call was a success
+        // Save accessToken, you will need it to request the service
         index();
     }
-    FACEBOOK.requestAccessToken(); // This will trigger a redirect
+    // authUrl is a String containing an absolute URL where the service should redirect the user back
+    FACEBOOK.requestVerificationCode(authUrl); // This will trigger a redirect
 }
 
 Once you have the access token associated to the current user, you can use it to query the service on behalf of the user:

framework/src/play/libs/OAuth2.java

@@ -7,6 +7,10 @@
 import play.mvc.Scope.Params;
 import play.mvc.results.Redirect;
 
+import play.libs.WS.HttpResponse;
+
+import com.google.gson.JsonObject;
+
 /**
  * Library to access ressources protected by OAuth 2.0. For OAuth 1.0a, see play.libs.OAuth.
  * See the facebook-oauth2 example for usage.
@@ -33,23 +37,112 @@ public static boolean isCodeResponse() {
         return Params.current().get("code") != null;
     }
 
-    public void requestAccessToken() {
-        String callbackURL = Request.current().getBase() + Request.current().url;
-        throw new Redirect(accessTokenURL
+    /**
+     * First step of the OAuth2 process: redirects the user to the authorization page
+     *
+     * @param callbackURL
+     */
+    public void retrieveVerificationCode(String callbackURL) {
+        throw new Redirect(authorizationURL
                 + "?client_id=" + clientid
                 + "&redirect_uri=" + callbackURL);
     }
 
-    public String getAccessToken() {
-        String callbackURL = Request.current().getBase() + Request.current().url;
+    public void retrieveVerificationCode() {
+        retrieveVerificationCode(Request.current().getBase() + Request.current().url);
+    }
+
+    public Response retrieveAccessToken(String callbackURL) {
         String accessCode = Params.current().get("code");
         Map<String, Object> params = new HashMap<String, Object>();
         params.put("client_id", clientid);
         params.put("client_secret", secret);
         params.put("redirect_uri", callbackURL);
         params.put("code", accessCode);
-        Map<String, String> response = WS.url(authorizationURL).params(params).get().getQueryString();
-        return response.get("access_token");
+        HttpResponse response = WS.url(accessTokenURL).params(params).get();
+        return new Response(response);
+    }
+
+    public Response retrieveAccessToken() {
+        return retrieveAccessToken(Request.current().getBase() + Request.current().url);
+    }
+
+    /**
+     * @deprecated Use @{link play.libs.OAuth2.retrieveVerificationCode()} instead
+     */
+    @Deprecated
+    public void requestAccessToken() {
+        retrieveVerificationCode();
+    }
+
+    /**
+     * @deprecated Use @{link play.libs.OAuth2.retrieveAccessToken()} instead
+     */
+    @Deprecated
+    public String getAccessToken() {
+        return retrieveAccessToken().accessToken;
+    }
+
+    public static class Response {
+        public final String accessToken;
+        public final Error error;
+        public final WS.HttpResponse httpResponse;
+        private Response(String accessToken, Error error, WS.HttpResponse response) {
+            this.accessToken = accessToken;
+            this.error = error;
+            this.httpResponse = response;
+        }
+        public Response(WS.HttpResponse response) {
+            this.httpResponse = response;
+            Map<String, String> querystring = response.getQueryString();
+            if (querystring.containsKey("access_token")) {
+                this.accessToken = querystring.get("access_token");
+                this.error = null;
+            } else {
+                this.accessToken = null;
+                this.error = Error.oauth2(response);
+            }
+        }
+        public static Response error(Error error, WS.HttpResponse response) {
+            return new Response(null, error, response);
+        }
+    }
+
+    public static class Error {
+        public final Type type;
+        public final String error;
+        public final String description;
+        public enum Type {
+            COMMUNICATION,
+            OAUTH,
+            UNKNOWN
+        }
+        private Error(Type type, String error, String description) {
+            this.type = type;
+            this.error = error;
+            this.description = description;
+        }
+        static Error communication() {
+            return new Error(Type.COMMUNICATION, null, null);
+        }
+        static Error oauth2(WS.HttpResponse response) {
+            if (response.getQueryString().containsKey("error")) {
+                Map<String, String> qs = response.getQueryString();
+                return new Error(Type.OAUTH,
+                        qs.get("error"),
+                        qs.get("error_description"));
+            } else if (response.getContentType().startsWith("text/javascript")) { // Stupid Facebook returns JSON with the wrong encoding
+                JsonObject jsonResponse = response.getJson().getAsJsonObject().getAsJsonObject("error");
+                return new Error(Type.OAUTH,
+                        jsonResponse.getAsJsonPrimitive("type").getAsString(),
+                        jsonResponse.getAsJsonPrimitive("message").getAsString());
+            } else {
+                return new Error(Type.UNKNOWN, null, null);
+            }
+        }
+        @Override public String toString() {
+            return "OAuth2 Error: " + type + " - " + error + " (" + description + ")";
+        }
     }
 
 }

framework/src/play/libs/WS.java

@@ -23,6 +23,7 @@
 import play.libs.OAuth.ServiceInfo;
 import play.libs.ws.WSAsync;
 import play.libs.ws.WSUrlFetch;
+import play.mvc.Http;
 import play.mvc.Http.Header;
 import play.utils.NoOpEntityResolver;
 
@@ -434,6 +435,13 @@ public static abstract class HttpResponse {
          */
         public abstract Integer getStatus();
 
+        /**
+         * @return true if the status code is 20x, false otherwise
+         */
+        public boolean success() {
+            return Http.StatusCode.success(this.getStatus());
+        }
+
         /**
          * The http response content type
          * @return the content type of the http response

samples-and-tests/facebook-oauth2/app/controllers/Application.java

@@ -11,9 +11,14 @@
 
 public class Application extends Controller {
 
+    // The following keys correspond to a test application
+    // registered on Facebook, and associated with the loisant.org domain.
+    // You need to bind loisant.org to your machine with /etc/hosts to
+    // test the application locally.
+
     public static OAuth2 FACEBOOK = new OAuth2(
-            "https://graph.facebook.com/oauth/access_token",
             "https://graph.facebook.com/oauth/authorize",
+            "https://graph.facebook.com/oauth/access_token",
             "95341411595",
             "8eff1b488da7fe3426f9ecaf8de1ba54"
     );
@@ -22,19 +27,20 @@ public static void index() {
         User u = connected();
         JsonObject me = null;
         if (u != null && u.access_token != null) {
-            me = WS.url("https://graph.facebook.com/me?access_token=%s", u.access_token).get().getJson().getAsJsonObject();
+            me = WS.url("https://graph.facebook.com/me?access_token=%s", WS.encode(u.access_token)).get().getJson().getAsJsonObject();
         }
         render(me);
     }
 
     public static void auth() {
         if (OAuth2.isCodeResponse()) {
             User u = connected();
-            u.access_token = FACEBOOK.getAccessToken();
+            OAuth2.Response response = FACEBOOK.retrieveAccessToken(authURL());
+            u.access_token = response.accessToken;
             u.save();
             index();
         }
-        FACEBOOK.requestAccessToken();
+        FACEBOOK.retrieveVerificationCode(authURL());
     }
 
     @Before
@@ -51,6 +57,10 @@ static void setuser() {
         renderArgs.put("user", user);
     }
 
+    static String authURL() {
+        return play.mvc.Router.getFullUrl("Application.auth");
+    }
+
     static User connected() {
         return (User)renderArgs.get("user");
     }