Using Google Reader API and OAuth in iPhone app

Question

I want to make an app that uses on the Google Reader API. But I'm finding out that there isn't an offical API for it - is there a problem using the unofficial API, in terms of App Store guidelines/approval? Would other apps (Reeder, etc) use this?

Also what is the best method for logging in? Is OAuth the preffered method? Is using Janrain a good idea?

Answer 1

Frankly Apple doesn't care if you use Google's unofficial API.

I worked for a customer on a RSS reader app that used Google Reader for syncing. We didn't use OAuth but the standard HTTP login which returns you a cookie where you'll have to extract a token from to use in consecutive calls to the various reader URLs.

I can post you the login code from my (old) proof of concept app. It uses ASIHTTP and some custom string categories. The idea is to send a login request, get the response and extract the session ID/auth code from the response's cookie header. Then you can use that session ID/auth code for consecutive calls.

#pragma mark -
#pragma mark login

//this is your sessionID token you get from the login
//use this in consecutive calls to google reader
//this method returns you the header string you have to add to your request
//[request addRequestHeader: @"Cookie" value: [self sidHeader]];
- (NSString *) sidHeader
{
    return [NSString stringWithFormat: @"SID=%@", [self sid]];
}

- (NSString *) authHeader
{
    return [NSString stringWithFormat: @"GoogleLogin auth=%@",[self auth]];
}


//login to your google account and get the session ID
- (void) login
{
    NSString *username = @"[email protected]";
    NSString *password = @"mypassword123";
    NSString *loginUrl = @"https://www.google.com/accounts/ClientLogin?client=NNW-Mac";
    NSString *source = @"NNW-Mac"; //let's fake NetNewsWire
    NSString *continueUrl = @"http://www.google.com";

    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:[NSURL URLWithString: loginUrl]]; // log in & get cookies
    [request addRequestHeader: @"User-Agent" value: @"NetNewsWire/3.2b25 (Mac OS X; http://www.newsgator.com/Individuals/NetNewsWire/)"];

    [request setPostValue: username forKey: @"Email"];
    [request setPostValue: password forKey: @"Passwd"];
    [request setPostValue: @"reader" forKey: @"service"];
    [request setPostValue: source forKey: @"source"];
    [request setPostValue: continueUrl forKey: @"continue"];

    [request setDelegate: self];
    [request setDidFailSelector: @selector(loginRequestFailed:)];
    [request setDidFinishSelector: @selector(loginRequestFinished:)];

    [request start];
}   

-(void)loginRequestFinished:(ASIHTTPRequest *)request
{
    NSString *responseString = [request responseString];

    //login failed
    if ([responseString containsString: @"Error=BadAuthentication" ignoringCase: YES])
    {
        [self setLastError: [self errorWithDescription: @"Bad Username/Passsword" code: 0x001 andErrorLevel: 0x00]];

        if ([delegate respondsToSelector: @selector(gReaderLoginDidFail:)])
        {
            [delegate gReaderLoginDidFail: self];
        }

        return NO;
    }

    //captcha required
    if ([responseString containsString: @"CaptchaRequired" ignoringCase: YES])
    {
        [self setLastError: [self errorWithDescription: @"Captcha Required" code: 0x001 andErrorLevel: 0x00]];

        if ([delegate respondsToSelector: @selector(gReaderLoginDidFail:)])
        {
            [delegate gReaderLoginDidFail: self];
        }

        return NO;
    }

    //extract SID + auth
    NSArray *respArray = [responseString componentsSeparatedByCharactersInSet: [NSCharacterSet newlineCharacterSet]];

    NSString *sidString = [respArray objectAtIndex: 0];
    sidString = [sidString stringByReplacingOccurrencesOfString: @"SID=" withString: @""];
    [self setSid: sidString];

NSString *authString = [respArray objectAtIndex: 2];
authString = [authString stringByReplacingOccurrencesOfString: @"Auth=" withString: @""];
[self setAuth: authString];
    //mesage delegate of success
    if ([delegate respondsToSelector: @selector(gReaderLoginDidSucceed:)])
    {
        [delegate gReaderLoginDidSucceed: self];
    }

    return YES;
}

- (void)loginRequestFailed:(ASIHTTPRequest *)request
{
    NSError *error = [request error];

    //NSLog(@"login request failed with error: %@", [error localizedDescription]);
    [self setLastError: error];

    if ([delegate respondsToSelector: @selector(gReaderLoginDidFail:)])
    {
        [delegate gReaderLoginDidFail: self];
    }

}

After login you can use sid and auth to forge requests to the Reader's API endpoints.

Example:

- (ASIHTTPRequest *) requestForAPIEndpoint: (NSString *) apiEndpoint
{
    ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString: apiEndpoint]];
    [request addRequestHeader: @"User-Agent" value: @"NetNewsWire/3.2b25 (Mac OS X; http://www.newsgator.com/Individuals/NetNewsWire/)"];
    [request addRequestHeader: @"Cookie" value: [self sidHeader]];
    [request addRequestHeader: @"Authorization" value: [self authHeader]];

    return request;
}

An interesting read about Google Reader and its private API is http://timbroder.com/2007/08/google-reader-api-functions.html

Please make sure to read the latest comments :)

/edit: I updated the code to use the auth header (which google introduced in june this year). I guess this would be the place to put your OAuth token in if you would use OAuth. guess

Answer 2

@daidai did you end up implementing everything right? and if so, are you able to help me out with my own application?