121 lines
3.4 KiB
JavaScript
121 lines
3.4 KiB
JavaScript
/**
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* Copyright 2017 Google Inc. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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const debugProtocol = require('debug')('hdfox:protocol');
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const EventEmitter = require('events');
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const {Events} = require('./Events');
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/**
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* @internal
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*/
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class Connection extends EventEmitter {
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/**
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* @param {!Puppeteer.ConnectionTransport} transport
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* @param {number=} delay
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*/
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constructor(transport, delay = 0) {
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super();
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this._lastId = 0;
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/** @type {!Map<number, {resolve: function, reject: function, error: !Error, method: string}>}*/
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this._callbacks = new Map();
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this._delay = delay;
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this._transport = transport;
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this._transport.onmessage = this._onMessage.bind(this);
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this._transport.onclose = this._onClose.bind(this);
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this._closed = false;
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}
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/**
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* @param {string} method
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* @param {!Object=} params
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* @return {!Promise<?Object>}
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*/
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send(method, params = {}) {
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const id = ++this._lastId;
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const message = JSON.stringify({id, method, params});
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debugProtocol('SEND ► ' + message);
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this._transport.send(message);
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return new Promise((resolve, reject) => {
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this._callbacks.set(id, {resolve, reject, error: new Error(), method});
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});
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}
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/**
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* @param {string} message
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*/
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async _onMessage(message) {
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if (this._delay)
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await new Promise(f => setTimeout(f, this._delay));
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debugProtocol('◀ RECV ' + message);
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const object = JSON.parse(message);
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if (object.id) {
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const callback = this._callbacks.get(object.id);
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// Callbacks could be all rejected if someone has called `.dispose()`.
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if (callback) {
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this._callbacks.delete(object.id);
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if (object.error)
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callback.reject(createProtocolError(callback.error, callback.method, object));
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else
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callback.resolve(object.result);
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}
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} else {
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this.emit(object.method, object.params);
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}
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}
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_onClose() {
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if (this._closed)
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return;
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this._closed = true;
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this._transport.onmessage = null;
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this._transport.onclose = null;
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for (const callback of this._callbacks.values())
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callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
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this._callbacks.clear();
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this.emit(Events.Connection.Disconnected);
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}
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dispose() {
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this._onClose();
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this._transport.close();
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}
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}
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/**
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* @param {!Error} error
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* @param {string} method
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* @param {{error: {message: string, data: any}}} object
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* @return {!Error}
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*/
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function createProtocolError(error, method, object) {
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let message = `Protocol error (${method}): ${object.error.message}`;
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if ('data' in object.error)
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message += ` ${object.error.data}`;
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return rewriteError(error, message);
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}
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/**
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* @param {!Error} error
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* @param {string} message
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* @return {!Error}
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*/
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function rewriteError(error, message) {
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error.message = message;
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return error;
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}
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module.exports = {Connection};
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