eu.trentorise.smartcampus.permissionprovider.auth.google.GoogleAuthHelper.java Source code

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/*******************************************************************************
 * Copyright 2012-2013 Trento RISE
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package eu.trentorise.smartcampus.permissionprovider.auth.google;

import java.io.IOException;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.Collection;

import javax.annotation.PostConstruct;

import org.codehaus.jackson.map.DeserializationConfig;
import org.codehaus.jackson.map.ObjectMapper;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeRequestUrl;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
import com.google.api.client.http.GenericUrl;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpRequestFactory;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;

/**
 * A helper class for Google's OAuth2 authentication API.
 * 
 * @version 20130224
 * @author Matyas Danter
 * 
 *         Modified by Giulia Canobbio.
 */
@Service("googleHelper")
public final class GoogleAuthHelper {

    @Value("${google.clientId}")
    private String clientId;

    @Value("${google.clientSecret}")
    private String clientSecret;

    @Value("${google.callbackURI}")
    private String callbackURI;

    // google authentication constants
    private static final Iterable<String> SCOPE = Arrays.asList(
            "https://www.googleapis.com/auth/userinfo.profile;https://www.googleapis.com/auth/userinfo.email;https://www.googleapis.com/auth/plus.me"
                    .split(";"));
    private static final String USER_INFO_URL = "https://www.googleapis.com/oauth2/v1/userinfo";
    private static final JsonFactory JSON_FACTORY = new com.google.api.client.json.jackson2.JacksonFactory();
    private static final HttpTransport HTTP_TRANSPORT = new NetHttpTransport();

    private GoogleAuthorizationCodeFlow flow;

    public static final String SESSION_GOOGLE_CHECK = "google-login";

    @SuppressWarnings("unused")
    @PostConstruct
    private void init() {
        flow = new GoogleAuthorizationCodeFlow.Builder(HTTP_TRANSPORT, JSON_FACTORY, clientId, clientSecret,
                (Collection<String>) SCOPE).build();
    }

    /**
     * Builds a login URL based on client ID, secret, callback URI, and scope.
     */
    public GoogleAuthorizationCodeRequestUrl buildLoginUrl() {
        final GoogleAuthorizationCodeRequestUrl url = flow.newAuthorizationUrl();
        return url.setRedirectUri(callbackURI).setState(generateStateToken());
    }

    /**
     * Generates a secure state token.
     */
    private String generateStateToken() {
        SecureRandom sr1 = new SecureRandom();
        return "google;" + sr1.nextInt();
    }

    /**
     * Expects an Authentication Code, and makes an authenticated request for
     * the user's profile information.
     * 
     * @param authCode
     *            : String, authentication code provided by google
     * @return {@link FBUser} formatted user profile information
     * @throws IOException
     */
    public GoogleUser getUserInfoJson(final String authCode) throws IOException {

        final GoogleTokenResponse response = flow.newTokenRequest(authCode).setRedirectUri(callbackURI).execute();
        final Credential credential = flow.createAndStoreCredential(response, null);
        final HttpRequestFactory requestFactory = HTTP_TRANSPORT.createRequestFactory(credential);

        // Make an authenticated request
        final GenericUrl url = new GenericUrl(USER_INFO_URL);
        final HttpRequest request = requestFactory.buildGetRequest(url);
        request.getHeaders().setContentType("application/json");

        final String jsonIdentity = request.execute().parseAsString();

        ObjectMapper obMapper = new ObjectMapper();
        obMapper.disable(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES);
        GoogleUser user = obMapper.readValue(jsonIdentity, GoogleUser.class);

        return user;

    }
}