[gnome-online-accounts] OAuth2Provider: add support for facebook client side auth flow

[Debarshi Ray <debarshir src gnome org>]

commit 82a65f575bf19498bdfd171635673d547826ddf1
Author: Cosimo Alfarano <cosimo alfarano collabora com>
Date:   Thu Mar 8 14:18:17 2012 +0000

    OAuth2Provider: add support for facebook client side auth flow
    
    When a client side auth flow is performed, there's no need for the
    client to pass the authorization code to the remote application in
    order to allow her to be authorized by the provider.
    
    Under this flow the user requests directly for the token (using
    request_type=token query, which should be set in the authorization uri
    builder), which allows the provider to give the application/client
    directly the access token,skipping a step in the
    authentication/authorization flow.
    
    This means that under a client side auth flow no authorization code is
    ever present.
    
    Fixes: https://bugzilla.gnome.org/672060

 src/goabackend/goaoauth2provider.c |  138 +++++++++++++++++++++++++++---------
 1 files changed, 105 insertions(+), 33 deletions(-)
---
diff --git a/src/goabackend/goaoauth2provider.c b/src/goabackend/goaoauth2provider.c
index 1bb5f6c..0ee82d3 100644
--- a/src/goabackend/goaoauth2provider.c
+++ b/src/goabackend/goaoauth2provider.c
@@ -18,6 +18,7 @@
  * Boston, MA 02111-1307, USA.
  *
  * Author: David Zeuthen <davidz redhat com>
+ *         Cosimo Alfarano <cosimo alfarano collabora co uk>
  */
 
 #include "config.h"
@@ -554,28 +555,88 @@ on_web_view_navigation_policy_decision_requested (WebKitWebView             *web
     {
       SoupMessage *message;
       SoupURI *uri;
-      GHashTable *key_value_pairs;
 
       message = webkit_network_request_get_message (request);
       uri = soup_message_get_uri (message);
-      key_value_pairs = soup_form_decode (uri->query);
 
-      data->authorization_code = g_strdup (g_hash_table_lookup (key_value_pairs, "code"));
-      if (data->authorization_code != NULL)
+      /* Two cases:
+       * the data we look for might be in the query part or in the fragment
+       * part of the URI.
+       *
+       * Currently only facebook client-side flow uses the fragment to pass
+       * the access_token and expiration, though, so we are actually looking
+       * for the auth code in the query and the access_token in the fragment.
+       * This might need changes (FIXME) to be more generalized */
+      if (soup_uri_get_query (uri) != NULL)
         {
-          gtk_dialog_response (data->dialog, GTK_RESPONSE_OK);
+          /* case 1, the data we are expecting is in the query part of the URI */
+          GHashTable *key_value_pairs;
+
+          key_value_pairs = soup_form_decode (uri->query);
+
+          data->authorization_code = g_strdup (g_hash_table_lookup (key_value_pairs, "code"));
+          if (data->authorization_code != NULL)
+            {
+              gtk_dialog_response (data->dialog, GTK_RESPONSE_OK);
+            }
+          else
+            {
+              g_set_error (&data->error,
+                           GOA_ERROR,
+                           GOA_ERROR_NOT_AUTHORIZED,
+                           _("Authorization response was \"%s\""),
+                           (const gchar *) g_hash_table_lookup (key_value_pairs, "error"));
+              gtk_dialog_response (data->dialog, GTK_RESPONSE_CLOSE);
+            }
+          g_hash_table_unref (key_value_pairs);
+          webkit_web_policy_decision_ignore (policy_decision);
+        }
+      else if (soup_uri_get_fragment (uri) != NULL)
+        {
+          /* case 2, the data we are expecting is in the fragment part of the
+           * URI */
+          GHashTable *key_value_pairs;
+
+          /* fragment is encoded into a key/value pairs for the token and
+           * expiration values, using the same syntax as a URL query */
+          key_value_pairs = soup_form_decode (soup_uri_get_fragment (uri));
+
+          /* we might use oauth2_proxy_extract_access_token() here but we need
+           * also to extract the expire time */
+          data->access_token = g_strdup (g_hash_table_lookup (key_value_pairs, "access_token"));
+          if (data->access_token != NULL)
+            {
+              gchar *expires_in_str = NULL;
+
+              expires_in_str = g_hash_table_lookup (key_value_pairs, "expires_in");
+              /* sometimes "expires_in" appears as "expires" */
+              if (expires_in_str == NULL)
+                expires_in_str = g_hash_table_lookup (key_value_pairs, "expires");
+
+              if (expires_in_str != NULL)
+                 data->access_token_expires_in = atoi (expires_in_str);
+
+              gtk_dialog_response (data->dialog, GTK_RESPONSE_OK);
+            }
+          else
+            {
+              g_set_error (&data->error,
+                           GOA_ERROR,
+                           GOA_ERROR_NOT_AUTHORIZED,
+                           _("Authorization response was \"%s\""),
+                           (const gchar *) g_hash_table_lookup (key_value_pairs, "error"));
+              gtk_dialog_response (data->dialog, GTK_RESPONSE_CLOSE);
+            }
+          g_hash_table_unref (key_value_pairs);
+          webkit_web_policy_decision_ignore (policy_decision);
         }
       else
         {
-          g_set_error (&data->error,
-                       GOA_ERROR,
-                       GOA_ERROR_NOT_AUTHORIZED,
-                       _("Authorization response was \"%s\""),
-                       (const gchar *) g_hash_table_lookup (key_value_pairs, "error"));
-          gtk_dialog_response (data->dialog, GTK_RESPONSE_CLOSE);
+          /* this actually means that something unexpected happened, either we
+           * did something wrong or the provider's flow changed */
+          goa_debug ("URI format not recognized, DEFAULT BEHAVIOUR");
+          return FALSE;
         }
-      g_hash_table_unref (key_value_pairs);
-      webkit_web_policy_decision_ignore (policy_decision);
       return TRUE; /* ignore the request */
     }
   else
@@ -720,7 +781,11 @@ get_tokens_and_identity (GoaOAuth2Provider  *provider,
     }
   data.dialog = dialog;
   gtk_dialog_run (GTK_DIALOG (dialog));
-  if (data.authorization_code == NULL)
+
+  /* we can have either the auth code, with which we'll obtain the token, or
+   * the token directly if we are using a client side flow, since we don't
+   * need to pass the code to the remote application */
+  if (data.authorization_code == NULL && data.access_token == NULL)
     {
       if (data.error == NULL)
         {
@@ -735,26 +800,31 @@ get_tokens_and_identity (GoaOAuth2Provider  *provider,
 
   gtk_widget_hide (GTK_WIDGET (dialog));
 
-  /* OK, we now have the authorization code... now we need to get the
-   * email address (to e.g. check if the account already exists on
-   * @client).. for that we need to get a (short-lived) access token
-   * and a refresh_token
-   */
-
-  /* TODO: run in worker thread */
-  data.access_token = get_tokens_sync (provider,
-                                       data.authorization_code,
-                                       NULL, /* refresh_token */
-                                       &data.refresh_token,
-                                       &data.access_token_expires_in,
-                                       NULL, /* GCancellable */
-                                       &data.error);
-  if (data.access_token == NULL)
+  if (data.authorization_code != NULL)
     {
-      g_prefix_error (&data.error, _("Error getting an Access Token: "));
-      goto out;
+      /* OK, we now have the authorization code... now we need to get the
+       * email address (to e.g. check if the account already exists on
+       * @client).. for that we need to get a (short-lived) access token
+       * and a refresh_token
+       */
+
+      /* TODO: run in worker thread */
+      data.access_token = get_tokens_sync (provider,
+                                           data.authorization_code,
+                                           NULL, /* refresh_token */
+                                           &data.refresh_token,
+                                           &data.access_token_expires_in,
+                                           NULL, /* GCancellable */
+                                           &data.error);
+      if (data.access_token == NULL)
+        {
+          g_prefix_error (&data.error, _("Error getting an Access Token: "));
+          goto out;
+        }
     }
 
+  g_assert (data.access_token != NULL);
+
   /* TODO: run in worker thread */
   data.identity = goa_oauth2_provider_get_identity_sync (provider,
                                                          data.access_token,
@@ -956,7 +1026,8 @@ goa_oauth2_provider_add_account (GoaProvider *_provider,
                                                       data.account_object_path));
 
   g_variant_builder_init (&builder, G_VARIANT_TYPE_VARDICT);
-  g_variant_builder_add (&builder, "{sv}", "authorization_code", g_variant_new_string (authorization_code));
+  if (authorization_code != NULL)
+    g_variant_builder_add (&builder, "{sv}", "authorization_code", g_variant_new_string (authorization_code));
   g_variant_builder_add (&builder, "{sv}", "access_token", g_variant_new_string (access_token));
   if (access_token_expires_in > 0)
     g_variant_builder_add (&builder, "{sv}", "access_token_expires_at",
@@ -1060,7 +1131,8 @@ goa_oauth2_provider_refresh_account (GoaProvider  *_provider,
     }
 
   g_variant_builder_init (&builder, G_VARIANT_TYPE_VARDICT);
-  g_variant_builder_add (&builder, "{sv}", "authorization_code", g_variant_new_string (authorization_code));
+  if (authorization_code != NULL)
+    g_variant_builder_add (&builder, "{sv}", "authorization_code", g_variant_new_string (authorization_code));
   g_variant_builder_add (&builder, "{sv}", "access_token", g_variant_new_string (access_token));
   if (access_token_expires_in > 0)
     g_variant_builder_add (&builder, "{sv}", "access_token_expires_at",