com.examples.abelanav2.storage.CloudStorage.java Source code

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Here is the source code for com.examples.abelanav2.storage.CloudStorage.java

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/*
 * Copyright 2015 Google, Inc. 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 com.examples.abelanav2.storage;

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.EmptyContent;
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.HttpResponse;
import com.google.api.client.http.HttpStatusCodes;
import com.google.api.client.http.HttpTransport;

import com.examples.abelanav2.BackendConstants;

import java.io.IOException;
import java.net.URLEncoder;
import java.security.GeneralSecurityException;
import java.util.Collections;
import java.util.logging.Logger;

/**
 * Utility class to interact with Google Cloud Storage.
 */
public class CloudStorage {

    /**
     * Logger.
     */
    private static final Logger LOGGER = Logger.getLogger(CloudStorage.class.getName());

    /**
     * The Google Cloud Storage scope.
     */
    private static final String STORAGE_SCOPE = "https://www.googleapis.com/auth/devstorage.full_control";

    /**
     * Constructor.
     */
    private CloudStorage() {
    }

    /**
     * Returns a Google Cloud Storage upload url.
     *
     * @param name the filename
     * @return a URL
     */
    public static String getUploadUrl(final String name) {

        try {
            GoogleCredential googleCredentials = GoogleCredential.getApplicationDefault()
                    .createScoped(Collections.singleton(STORAGE_SCOPE));

            String uri = "https://www.googleapis.com/upload/storage/v1/b/"
                    + URLEncoder.encode(BackendConstants.UPLOAD_BUCKET_NAME, "UTF-8")
                    + "/o?uploadType=resumable&name=" + URLEncoder.encode(name, "UTF-8");

            HttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
            HttpRequestFactory requestFactory = httpTransport.createRequestFactory(googleCredentials);
            GenericUrl url = new GenericUrl(uri);
            HttpRequest request = requestFactory.buildPostRequest(url, new EmptyContent());
            try {
                HttpResponse response = request.execute();

                if (response.getStatusCode() == HttpStatusCodes.STATUS_CODE_OK) {
                    return response.getHeaders().getLocation();
                } else {
                    LOGGER.severe("Could not get upload URL, HTTP code = " + response.getStatusCode());
                }
            } catch (IOException e) {
                LOGGER.severe("API request to Google Cloud Storage failed: " + e.getMessage());
            }

        } catch (IOException e) {
            LOGGER.severe("Could not get credentials: " + e.getMessage());
        } catch (GeneralSecurityException e) {
            LOGGER.severe("Could not start the transport layer for upload: " + e.getMessage());
        }
        return null;
    }
}