Google OAuth2.0 for scribe-java

Google2APi.java

package org.scribe.builder.api;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.scribe.exceptions.OAuthException;
import org.scribe.extractors.AccessTokenExtractor;
import org.scribe.model.OAuthConfig;
import org.scribe.model.OAuthConstants;
import org.scribe.model.OAuthRequest;
import org.scribe.model.Response;
import org.scribe.model.Token;
import org.scribe.model.Verb;
import org.scribe.model.Verifier;
import org.scribe.oauth.OAuth20ServiceImpl;
import org.scribe.oauth.OAuthService;
import org.scribe.utils.OAuthEncoder;
import org.scribe.utils.Preconditions;

/**
 * Google OAuth2.0 
 * Released under the same license as scribe (MIT License)
 * @author yincrash
 * 
 */
public class Google2Api extends DefaultApi20 {

    private static final String AUTHORIZE_URL = "https://accounts.google.com/o/oauth2/auth?response_type=code&client_id=%s&redirect_uri=%s";
    private static final String SCOPED_AUTHORIZE_URL = AUTHORIZE_URL + "&scope=%s";

    @Override
    public String getAccessTokenEndpoint() {
        return "https://accounts.google.com/o/oauth2/token";
    }
    
    @Override
    public AccessTokenExtractor getAccessTokenExtractor() {
        return new AccessTokenExtractor() {
            
            @Override
            public Token extract(String response) {
                Preconditions.checkEmptyString(response, "Response body is incorrect. Can't extract a token from an empty string");

                Matcher matcher = Pattern.compile("\"access_token\" : \"([^&\"]+)\"").matcher(response);
                if (matcher.find())
                {
                  String token = OAuthEncoder.decode(matcher.group(1));
                  return new Token(token, "", response);
                } 
                else
                {
                  throw new OAuthException("Response body is incorrect. Can't extract a token from this: '" + response + "'", null);
                }
            }
        };
    }

    @Override
    public String getAuthorizationUrl(OAuthConfig config) {
        // Append scope if present
        if (config.hasScope()) {
            return String.format(SCOPED_AUTHORIZE_URL, config.getApiKey(),
                    OAuthEncoder.encode(config.getCallback()),
                    OAuthEncoder.encode(config.getScope()));
        } else {
            return String.format(AUTHORIZE_URL, config.getApiKey(),
                    OAuthEncoder.encode(config.getCallback()));
        }
    }
    
    @Override
    public Verb getAccessTokenVerb() {
        return Verb.POST;
    }
    
    @Override
    public OAuthService createService(OAuthConfig config) {
        return new GoogleOAuth2Service(this, config);
    }
    
    private class GoogleOAuth2Service extends OAuth20ServiceImpl {

        private static final String GRANT_TYPE_AUTHORIZATION_CODE = "authorization_code";
        private static final String GRANT_TYPE = "grant_type";
        private DefaultApi20 api;
        private OAuthConfig config;

        public GoogleOAuth2Service(DefaultApi20 api, OAuthConfig config) {
            super(api, config);
            this.api = api;
            this.config = config;
        }
        
        @Override
        public Token getAccessToken(Token requestToken, Verifier verifier) {
            OAuthRequest request = new OAuthRequest(api.getAccessTokenVerb(), api.getAccessTokenEndpoint());
            switch (api.getAccessTokenVerb()) {
            case POST:
                request.addBodyParameter(OAuthConstants.CLIENT_ID, config.getApiKey());
                request.addBodyParameter(OAuthConstants.CLIENT_SECRET, config.getApiSecret());
                request.addBodyParameter(OAuthConstants.CODE, verifier.getValue());
                request.addBodyParameter(OAuthConstants.REDIRECT_URI, config.getCallback());
                request.addBodyParameter(GRANT_TYPE, GRANT_TYPE_AUTHORIZATION_CODE);
                break;
            case GET:
            default:
                request.addQuerystringParameter(OAuthConstants.CLIENT_ID, config.getApiKey());
                request.addQuerystringParameter(OAuthConstants.CLIENT_SECRET, config.getApiSecret());
                request.addQuerystringParameter(OAuthConstants.CODE, verifier.getValue());
                request.addQuerystringParameter(OAuthConstants.REDIRECT_URI, config.getCallback());
                if(config.hasScope()) request.addQuerystringParameter(OAuthConstants.SCOPE, config.getScope());
            }
            Response response = request.send();
            return api.getAccessTokenExtractor().extract(response.getBody());
        }
    }

}

Thanks, it works like a charm (used the Facebook example to get a clue on how to use it)

thanks, I was searching for this for more than 2hrs :-)..

Thank you.

It was pretty cool, could go in a pull request

Thank you!

Thank you.
This works perfectly fine with grails oauth plugin also.
Thanks a lot.

"Google has deprecated OpenID 2.0 and will shut it down after a migration period" (May 19, 2014.) Your code can help peoples with Scribe. You don't send a pull request on the origin project with this ? The current project has only "GoogleApi extends DefaultApi10a"

Thank you.
Really great contribution. I was struggling with this for ages.

anyone could guide me how to use this?
by calling ".getRequestToken()" it returns an exception,

Usage exemple, is the adaption of the Facebook scribe exemple :
https://github.com/fernandezpablo85/scribe-java/blob/master/src/test/java/org/scribe/examples/FacebookExample.java

   private static final String PROTECTED_RESOURCE_URL = "https://www.googleapis.com/userinfo/v2/me";
   private static final String SCOPE = "openid email profile";

   public static void main(String[] args)  {

    // Replace these with your own api key and secret
    String apiKey = YourKeys.GOOGLE_API_KEY;
    String apiSecret = YourKeys.GOOGLE_API_SECRET;
    OAuthService service = new ServiceBuilder().provider(Google2Api.class).apiKey(apiKey).scope(SCOPE)
            .apiSecret(apiSecret).callback(YourKeys.CALLBACK).build();
    Scanner in = new Scanner(System.in);
    System.out.println("=== " + NETWORK_NAME + "'s OAuth Workflow ===");
    System.out.println();

    // Obtain the Authorization URL
    System.out.println("Fetching the Authorization URL...");
    String authorizationUrl = service.getAuthorizationUrl(EMPTY_TOKEN);
    System.out.println("Got the Authorization URL!");
    System.out.println("Now go and authorize Scribe here:");
    System.out.println(authorizationUrl);
    System.out.println("And paste the authorization code here");
    System.out.print(">>");
    Verifier verifier = new Verifier(in.nextLine());
    System.out.println();

    // Trade the Request Token and Verfier for the Access Token
    System.out.println("Trading the Request Token for an Access Token...");
    Token accessToken = service.getAccessToken(EMPTY_TOKEN, verifier);
    System.out.println("Got the Access Token!");
    System.out.println("(if your curious it looks like this: " + accessToken + " )");
    System.out.println();

    // Now let's go and ask for a protected resource!
    System.out.println("Now we're going to access a protected resource...");
    OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
    service.signRequest(accessToken, request);
    Response response = request.send();
    System.out.println("Got it! Lets see what we found...");
    System.out.println();
    System.out.println(response.getCode());
    System.out.println(response.getBody());

    System.out.println();
    System.out.println("Thats it man! Go and build something awesome with Scribe! :)");

}

for those who need a help on how to use this class, see this tutorial