to.lean.tools.gmail.importer.gmail.Authorizer.java Source code

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Here is the source code for to.lean.tools.gmail.importer.gmail.Authorizer.java

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/*
 * Copyright 2015 The Mail Importer Authors. All rights reserved.
 *
 * 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 to.lean.tools.gmail.importer.gmail;

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.auth.oauth2.StoredCredential;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.auth.oauth2.GoogleOAuthConstants;
import com.google.api.client.googleapis.auth.oauth2.GoogleTokenResponse;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.util.store.DataStore;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.Profile;
import com.google.common.base.Charsets;
import com.google.common.base.Verify;
import com.google.common.collect.ImmutableList;
import com.google.common.io.CharSource;
import com.google.common.io.Resources;

import javax.inject.Inject;
import javax.inject.Provider;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;

/**
 * Encapsulates the authorization and authentication flow.
 */
class Authorizer implements Provider<Credential> {
    private HttpTransport httpTransport;
    private JsonFactory jsonFactory;
    private User user;

    @Inject
    public Authorizer(User user, HttpTransport httpTransport, JsonFactory jsonFactory) {
        this.httpTransport = httpTransport;
        this.jsonFactory = jsonFactory;
        this.user = user;
    }

    public Credential get() {
        try {
            GoogleClientSecrets clientSecrets = loadGoogleClientSecrets(jsonFactory);

            DataStore<StoredCredential> dataStore = getStoredCredentialDataStore();

            // Allow user to authorize via url.
            GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(httpTransport, jsonFactory,
                    clientSecrets, ImmutableList.of(GmailScopes.GMAIL_MODIFY, GmailScopes.GMAIL_READONLY))
                            .setCredentialDataStore(dataStore).setAccessType("offline").setApprovalPrompt("auto")
                            .build();

            // First, see if we have a stored credential for the user.
            Credential credential = flow.loadCredential(user.getEmailAddress());

            // If we don't, prompt them to get one.
            if (credential == null) {
                String url = flow.newAuthorizationUrl().setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI)
                        .build();
                System.out.println("Please open the following URL in your browser then "
                        + "type the authorization code:\n" + url);

                // Read code entered by user.
                System.out.print("Code: ");
                System.out.flush();
                BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                String code = br.readLine();

                // Generate Credential using retrieved code.
                GoogleTokenResponse response = flow.newTokenRequest(code)
                        .setRedirectUri(GoogleOAuthConstants.OOB_REDIRECT_URI).execute();

                credential = flow.createAndStoreCredential(response, user.getEmailAddress());
            }

            Gmail gmail = new Gmail.Builder(httpTransport, jsonFactory, credential)
                    .setApplicationName(GmailServiceModule.APP_NAME).build();

            Profile profile = gmail.users().getProfile(user.getEmailAddress()).execute();

            System.out.println(profile.toPrettyString());
            return credential;
        } catch (IOException exception) {
            throw new RuntimeException(exception);
        }
    }

    private GoogleClientSecrets loadGoogleClientSecrets(JsonFactory jsonFactory) throws IOException {
        URL url = Resources.getResource("client_secret.json");
        CharSource inputSupplier = Resources.asCharSource(url, Charsets.UTF_8);
        return GoogleClientSecrets.load(jsonFactory, inputSupplier.openStream());
    }

    private DataStore<StoredCredential> getStoredCredentialDataStore() throws IOException {
        File userHomeDir = getUserHomeDir();
        File mailimporter = new File(userHomeDir, ".mailimporter");
        FileDataStoreFactory dataStoreFactory = new FileDataStoreFactory(mailimporter);
        return dataStoreFactory.getDataStore("credentials");
    }

    private File getUserHomeDir() {
        File userHome = new File(System.getProperty("user.home"));
        Verify.verify(userHome.exists() && userHome.canRead(), "Can not find user's home: %s", userHome);
        return userHome;
    }
}