com.google.appengine.tools.cloudstorage.oauth.AbstractOAuthURLFetchService.java Source code

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Here is the source code for com.google.appengine.tools.cloudstorage.oauth.AbstractOAuthURLFetchService.java

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/*
 * Copyright 2012 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.google.appengine.tools.cloudstorage.oauth;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.appengine.api.urlfetch.HTTPHeader;
import com.google.appengine.api.urlfetch.HTTPRequest;
import com.google.appengine.api.urlfetch.HTTPResponse;
import com.google.appengine.api.urlfetch.URLFetchService;
import com.google.appengine.tools.cloudstorage.ExceptionHandler;
import com.google.appengine.tools.cloudstorage.RetryHelper;
import com.google.appengine.tools.cloudstorage.RetryHelperException;
import com.google.appengine.tools.cloudstorage.RetryParams;
import com.google.apphosting.api.ApiProxy.ApiDeadlineExceededException;
import com.google.apphosting.api.ApiProxy.RPCFailedException;
import com.google.apphosting.api.ApiProxy.UnknownException;
import com.google.common.util.concurrent.Futures;

import java.io.IOException;
import java.util.concurrent.Callable;
import java.util.concurrent.Future;

/**
 * An OAuthURLFetchService decorator that adds the authorization header to the http request.
 *
 */
abstract class AbstractOAuthURLFetchService implements OAuthURLFetchService {

    private final URLFetchService urlFetch;

    private static final ExceptionHandler EXCEPTION_HANDLER = new ExceptionHandler.Builder()
            .retryOn(UnknownException.class, RPCFailedException.class, ApiDeadlineExceededException.class).build();

    private static final RetryParams RETRY_PARAMS = new RetryParams.Builder().initialRetryDelayMillis(10)
            .totalRetryPeriodMillis(10000).build();

    AbstractOAuthURLFetchService(URLFetchService urlFetch) {
        this.urlFetch = checkNotNull(urlFetch);
    }

    protected abstract String getToken();

    private HTTPRequest createAuthorizeRequest(final HTTPRequest req) throws RetryHelperException {
        String token = RetryHelper.runWithRetries(new Callable<String>() {
            @Override
            public String call() {
                return getToken();
            }
        }, RETRY_PARAMS, EXCEPTION_HANDLER);
        HTTPRequest request = URLFetchUtils.copyRequest(req);
        request.setHeader(new HTTPHeader("Authorization", "Bearer " + token));
        return request;
    }

    @Override
    public HTTPResponse fetch(HTTPRequest req) throws IOException, RetryHelperException {
        HTTPRequest authorizedRequest = createAuthorizeRequest(req);
        return urlFetch.fetch(authorizedRequest);
    }

    @Override
    public Future<HTTPResponse> fetchAsync(HTTPRequest req) {
        HTTPRequest authorizedRequest;
        try {
            authorizedRequest = createAuthorizeRequest(req);
        } catch (RetryHelperException e) {
            return Futures.immediateFailedCheckedFuture(e);
        }
        return urlFetch.fetchAsync(authorizedRequest);
    }
}