de.smilix.gaeCalenderGateway.service.auth.AuthService.java Source code

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Here is the source code for de.smilix.gaeCalenderGateway.service.auth.AuthService.java

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/*
 * Copyright (c) 2010 Google Inc.
 *
 * 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 de.smilix.gaeCalenderGateway.service.auth;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Collections;
import java.util.logging.Logger;

import javax.servlet.http.HttpServletRequest;

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.appengine.datastore.AppEngineDataStoreFactory;
import com.google.api.client.extensions.appengine.http.UrlFetchTransport;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.http.GenericUrl;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.store.DataStoreFactory;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.CalendarScopes;

import de.smilix.gaeCalenderGateway.common.Utils;
import de.smilix.gaeCalenderGateway.service.data.ConfigurationService;

public class AuthService {

    private static final Logger LOG = Logger.getLogger(AuthService.class.getName());

    private static final String CLIENT_SECRETS_JSON = "/client_secrets.json";

    /**
     * Global instance of the {@link DataStoreFactory}. The best practice is to make it a single
     * globally shared instance across your application.
     */
    private static final AppEngineDataStoreFactory DATA_STORE_FACTORY = AppEngineDataStoreFactory
            .getDefaultInstance();

    /** Global instance of the HTTP transport. */
    static final HttpTransport HTTP_TRANSPORT = new UrlFetchTransport();

    /** Global instance of the JSON factory. */
    static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();

    private static AuthService instance;

    public static AuthService get() {
        if (instance == null) {
            instance = new AuthService();
        }

        return instance;
    }

    private GoogleClientSecrets clientSecrets = null;

    private AuthService() {
    }

    private GoogleClientSecrets getClientCredential() throws AuthException {
        if (this.clientSecrets == null) {
            InputStream ressourceStream = AuthService.class.getResourceAsStream(CLIENT_SECRETS_JSON);
            if (ressourceStream == null) {
                throw new AuthException("No '" + CLIENT_SECRETS_JSON + "' file found.");
            }

            try {
                this.clientSecrets = GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(ressourceStream));
            } catch (IOException e) {
                throw new AuthException("Error loading '" + CLIENT_SECRETS_JSON + "' file: " + e.getMessage(), e);
            }

            if (Utils.isEmpty(this.clientSecrets.getDetails().getClientId())
                    || Utils.isEmpty(this.clientSecrets.getDetails().getClientSecret())) {
                throw new AuthException("The '" + CLIENT_SECRETS_JSON + "' file is incomplete.");
            }
        }
        return this.clientSecrets;
    }

    public String getRedirectUri(HttpServletRequest req) {
        GenericUrl url = new GenericUrl(req.getRequestURL().toString());
        url.setRawPath("/oauth2callback");
        return url.build();
    }

    public GoogleAuthorizationCodeFlow newFlow() throws IOException, AuthException {
        return new GoogleAuthorizationCodeFlow.Builder(HTTP_TRANSPORT, JSON_FACTORY, getClientCredential(),
                Collections.singleton(CalendarScopes.CALENDAR)).setDataStoreFactory(DATA_STORE_FACTORY)
                        .setAccessType("offline").setApprovalPrompt("force").build();
    }

    public boolean hasClientCredentials() throws IOException, AuthException {
        String userId = ConfigurationService.getConfig().getUserId();
        if (Utils.isEmpty(userId)) {
            LOG.fine("userId is empty");
            return false;
        }
        Credential credential = newFlow().loadCredential(userId);
        boolean result = credential != null && !Utils.isEmpty(credential.getAccessToken())
                && !Utils.isEmpty(credential.getRefreshToken());
        if (!result) {
            if (credential == null) {
                LOG.fine("credential is null");
            } else {
                LOG.fine("refresh token: " + credential.getRefreshToken());
                LOG.fine("access token: " + credential.getAccessToken());
            }
        }
        return result;
    }

    public Calendar loadCalendarClient() throws IOException, AuthException {
        String userId = ConfigurationService.getConfig().getUserId();
        if (Utils.isEmpty(userId)) {
            throw new IllegalStateException("UserId must set before.");
        }
        LOG.fine("Using userId: " + userId);

        GoogleAuthorizationCodeFlow newFlow = newFlow();
        Credential credential = newFlow.loadCredential(userId);

        if (credential.getRefreshToken() == null) {
            LOG.warning("no refresh token :(");

            // try this: http://stackoverflow.com/questions/10827920/google-oauth-refresh-token-is-not-being-received
            //      GoogleAuthorizationCodeRequestUrl authorizationUrl = newFlow.newAuthorizationUrl();
            //      authorizationUrl.setRedirectUri(getRedirectUri(req));
            //      onAuthorization(req, resp, authorizationUrl);
            //      credential = null;

            // ...

            //      RefreshTokenRequest r = new RefreshTokenRequest(transport, jsonFactory, tokenServerUrl, refreshToken)
            //      GoogleRefreshTokenRequest g = new GoogleRefreshTokenRequest(transport, jsonFactory, refreshToken, clientId, clientSecret)
        } else {
            LOG.fine("got refresh token: " + credential.getRefreshToken());
        }

        return new Calendar.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential)
                .setApplicationName("gaeCalendarGateway").build();
    }
}