com.google.api.gwt.client.GoogleApiRequestTransport.java Source code

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Here is the source code for com.google.api.gwt.client.GoogleApiRequestTransport.java

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/*
 * Copyright 2011 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 com.google.api.gwt.client;

import com.google.gwt.core.client.Callback;
import com.google.gwt.core.client.JsonUtils;
import com.google.web.bindery.requestfactory.shared.RequestTransport;
import com.google.web.bindery.requestfactory.shared.ServerFailure;

import java.util.HashMap;
import java.util.Map;

/**
 * {@link RequestTransport} designed to communicate with Google APIs.
 *
 * @author jasonhall@google.com (Jason Hall)
 */
public class GoogleApiRequestTransport implements RequestTransport {

    private final String apiKey;
    private final String userAgent;
    private final Map<String, String> headers = new HashMap<String, String>();
    private final String baseUrl;

    /**
     * @param applicationName the application name to be sent in the User-Agent header of requests.
     * @param apiKey an optional API key. See https://code.google.com/apis/console, or {@code null} to
     *     send no API key.
     */
    public GoogleApiRequestTransport(String applicationName, String apiKey) {
        this(applicationName, apiKey, "https://content.googleapis.com");
    }

    /**
     * @param applicationName the application name to be sent in the User-Agent header of requests.
     * @param apiKey an optional API key. See https://code.google.com/apis/console, or {@code null} to
     *     send no API key.
     * @param baseUrl the base URL of the Discovery service to use
     */
    public GoogleApiRequestTransport(String applicationName, String apiKey, String baseUrl) {
        this.apiKey = apiKey;
        this.userAgent = (applicationName == null ? "" : (applicationName + " ")) + "google-api-gwt-client/0.1";
        this.baseUrl = baseUrl;
    }

    private native void nativeSend(String payload, TransportReceiver receiver) /*-{
                                                                               var callback =  $entry(function(result) {
                                                                               if ('error' in result) {
                                                                               var code = result['error']['code'];
                                                                               var message = result['error']['message'];
                                                                               @com.google.api.gwt.client.GoogleApiRequestTransport::handleError(*)
                                                                               (code, message, receiver);
                                                                               } else {
                                                                               var resultStr = JSON.stringify(result);
                                                                               receiver.
                                                                               @com.google.web.bindery.requestfactory.shared.RequestTransport.TransportReceiver::onTransportSuccess(*)
                                                                               (resultStr);
                                                                               }
                                                                               });
                                                                                   
                                                                               // TODO(jasonhall): Find some way to avoid this.
                                                                               eval('var payloadObject = ' + payload);
                                                                                   
                                                                               var params = payloadObject['params'] || {};
                                                                               params['key'] = this.@com.google.api.gwt.client.GoogleApiRequestTransport::apiKey;
                                                                               params['root'] = this.@com.google.api.gwt.client.GoogleApiRequestTransport::baseUrl;
                                                                                   
                                                                               // TODO(jasonhall): Set the X-JavaScript-User-Agent header
                                                                                   
                                                                               $wnd.gapi.client.rpcRequest(payloadObject.method,
                                                                               payloadObject.apiVersion, params).execute(callback);
                                                                               }-*/;

    private static void handleError(int code, String message, TransportReceiver receiver) {
        receiver.onTransportFailure(new ServerFailure(code + " " + message));
    }

    @Override
    public void send(final String payload, final TransportReceiver receiver) {
        // Ensure that the API library is loaded. If it is, this callback will be executed immediately.
        GoogleApiLoader.get().load(new Callback<Void, Exception>() {
            @Override
            public void onSuccess(Void v) {
                makeRequest(payload, receiver);
            }

            @Override
            public void onFailure(Exception e) {
                receiver.onTransportFailure(new ServerFailure(e.getMessage()));
            }
        });
    }

    private void makeRequest(String payload, TransportReceiver receiver) {
        if (JsonUtils.safeToEval(payload)) {
            nativeSend(payload, receiver);
        } else {
            receiver.onTransportFailure(new ServerFailure("Request payload is invalid."));
        }
    }
}