Question

I’m new to web server programming so maybe I’m doing this the wrong way, but here’s what I’m trying to do:

1. The user authenticates using a native iOS app against the server “https://www.googleapis.com/auth/plus.me”. I’m using the ,
   GTMOAuth2 classes to handle the authorization. I’ve successfully retrieved a valid token, so this part works.

2. I’m now trying to POST JSON data to a google-app-engine web servlet as an authenticated user by using the authentication token I obtained in step 1. Here’s the code I’m using:

   - (void)postDictionary:(NSMutableDictionary *)dict toURL:(NSMutableString *)urlString     withAuthToken:(GTMOAuth2Authentication *)authToken delegate:(id)connectDelegate
   {
   
   if( ![NSJSONSerialization isValidJSONObject:dict] )
   {
       NSLog(@"JSON Data is Invalid!");
       return;
   }
   NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dict
                                                  options:0 error:nil];
   NSMutableString *serverURL = [[NSMutableString alloc] initWithString:urlString];
   //DEBUG
   NSLog(@"sent URL: %@", serverURL);
   
   NSURL *url = [[NSURL alloc] initWithString:serverURL];
   NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
   
   // Execute URL Asynchronously
   // Make sure we "Post" the data to the server
   [request setHTTPMethod:@"POST"];
   [request setHTTPBody:jsonData];
   [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
   [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
   [request setValue:@"json" forHTTPHeaderField:@"Data-Type"];
   [request setValue:[NSString stringWithFormat:@"%d",
                  [jsonData length]] forHTTPHeaderField:@"Content-Length"];
   
   // We need to send the authentication information to the server.
   [request setValue:CLIENT_ID forHTTPHeaderField:@"client_id"];
   [request setValue:CLIENT_SECRET forHTTPHeaderField:@"client_secret"];
   [request setValue:authToken.accessToken forHTTPHeaderField:@"Authorization: GoogleLogin auth"];
   // Make sure we can authenticate on HTTP instead of just HTTPS
   authToken.shouldAuthorizeAllRequests=YES;   // USED FOR TESTING ON LOCALHOST ONLY!!!
   
   
   // Let's Try the Fetcher method...
   GTMHTTPFetcher* myFetcher = [GTMHTTPFetcher fetcherWithRequest:request];
   [myFetcher setAuthorizer:authToken];
   [myFetcher beginFetchWithDelegate:self
               didFinishSelector:@selector(myFetcher:finishedWithData:error:)];
    return;
   }
   

Currently the server I’m trying to post to is is running on “http://localhost:8888/mywebapp”.

1. On the web server, I’m trying to authenticate the user using the following java code:

   public void doPost(HttpServletRequest req, HttpServletResponse resp)
               throws IOException {
   // Perform Authentication...
   UserService userService = UserServiceFactory.getUserService();
   User user = userService.getCurrentUser();
   
   if( user != null ) {
       System.out.println("User: "+user.getNickname());
   } else {
       sendError( "You must login first!",  resp );
       return;
   }
   ...
   

The UserService never indicates a user is logged in. I’ve tried several different things, but haven’t had any success. My app just gets the “You must login first!” error message. Any ideas?

Answer 1

I solved my problem.

1. I had to switch to the OAuth 1 protocol instead of the OAuth 2 protocol. According to the documentation I read, the OAuth 2 isn’t supported for Google App Engine yet (Does anyone know differently?). So I used the library GTM-OAUTH instead of the GTM-OAUTH2 library in my iOS app. I used the “OAuthSampleTouch” example as a basis for using the library.

2. I needed to register my google-app-engine URL with Google, using https://accounts.google.com/managedomains.
   That gave me a ConsumerKey and ConsumerSecret I could use in my iPhone app when calling the GTM-OAUTH Library.

3. I modified my GAE server code to use the OAUTH token:

   public void doPost(HttpServletRequest req, HttpServletResponse resp)
       throws IOException {
   // Perform Authentication...
     User user = null;
     try {
     OAuthService oathService = OAuthServiceFactory.getOAuthService();
     user = oathService.getCurrentUser();
     System.out.println("Logged in! YAY!!!");
     } catch (OAuthRequestException e) {
        System.out.println("Authentication Failed! "+e);
     }
     ...
   

I also appended the Token into the URL, I’m not sure if this is required or not…

Example:
URL=”https://my-app.appspot.com/myservlet?token=XXXXXXXXXXXXXXXX”