LinkedIn API, OAuth and Scribe

Hello everyone.
We know OAuth is a beautiful authentication service… in terms of concept. But when it comes to implementation, it’s a real pain in the ass. I found myself into fighting against it using Java to authenticate on LinkedIn, the popular reputation network. After a few minutes I was crying like a baby. It’s not impossible to do it by yourself, but the patience required is more than I could offer.

So I found out this library, named Scribe written by the brilliant software engineer Pablo Fernandez  that definitely helped a lot.
I copied and run his server side authentication example and worked like charm.

I’m taking his example for Twitter right from here site here (hope you don’t mind Pablo) https://github.com/fernandezpablo85/scribe-java/wiki/getting-started :

OAuthService service = new ServiceBuilder()
                           .provider(TwitterApi.class)
                           .apiKey("your_api_key")
                           .apiSecret("your_api_secret")
                           .build();
Token requestToken = service.getRequestToken();
String authUrl = service.getAuthorizationUrl(requestToken); Verifier v = new Verifier("verifier you got from the user");
Token accessToken = service.getAccessToken(requestToken, verifier); // the requestToken you had from step 2
OAuthRequest request = new OAuthRequest(Verb.GET, "http://api.twitter.com/1/account/verify_credentials.xml");
service.signRequest(accessToken, request); // the access token from step 4
Response response = request.send();
System.out.println(response.getBody());

And guess what, it worked like charm with LinkedIn also (just changing a few details you can find by yourself).

This is all beautiful… a pity what I had to implement was a client side authentication. The user authenticates on a LinkedIn popup, generates a cookie with an auth token in it that is then sent to our server that must use it run an exchange with the LinkedIn server to obtain a real access token… This is a very powerful authentication process, but implementing it is, again, a work of patience.

And again, reading through LinkedIn developers forums, Scribe shows up again, used like this:

OAuthRequest req = new OAuthRequest(Verb.POST, "https://api.linkedin.com/uas/oauth/accessToken");
req.addBodyParameter("xoauth_oauth2_access_token", jsnpToken);
Token token = new Token("","");
service.signRequest(token, req);
Response resp = req.send();
String body = resp.getBody();

where “jsnpToken” is the auth token passed through the cookie and “body” contains a string describing the real access token you’ll use to sign further requests.

Wasn’t that easy?

Thanks Pablo!