puppeteer/experimental/puppeteer-firefox/lib/Connection.js

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/**
* Copyright 2017 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.
*/
const debugProtocol = require('debug')('hdfox:protocol');
const EventEmitter = require('events');
const {Events} = require('./Events');
/**
* @internal
*/
class Connection extends EventEmitter {
/**
* @param {!Puppeteer.ConnectionTransport} transport
* @param {number=} delay
*/
constructor(url, transport, delay = 0) {
super();
this._url = url;
this._lastId = 0;
/** @type {!Map<number, {resolve: function, reject: function, error: !Error, method: string}>}*/
this._callbacks = new Map();
this._delay = delay;
this._transport = transport;
this._transport.onmessage = this._onMessage.bind(this);
this._transport.onclose = this._onClose.bind(this);
this._closed = false;
}
url() {
return this._url;
}
/**
* @param {string} method
* @param {!Object=} params
* @return {!Promise<?Object>}
*/
send(method, params = {}) {
const id = ++this._lastId;
const message = JSON.stringify({id, method, params});
debugProtocol('SEND ► ' + message);
this._transport.send(message);
return new Promise((resolve, reject) => {
this._callbacks.set(id, {resolve, reject, error: new Error(), method});
});
}
/**
* @param {string} message
*/
async _onMessage(message) {
if (this._delay)
await new Promise(f => setTimeout(f, this._delay));
debugProtocol('◀ RECV ' + message);
const object = JSON.parse(message);
if (object.id) {
const callback = this._callbacks.get(object.id);
// Callbacks could be all rejected if someone has called `.dispose()`.
if (callback) {
this._callbacks.delete(object.id);
if (object.error)
callback.reject(createProtocolError(callback.error, callback.method, object));
else
callback.resolve(object.result);
}
} else {
this.emit(object.method, object.params);
}
}
_onClose() {
if (this._closed)
return;
this._closed = true;
this._transport.onmessage = null;
this._transport.onclose = null;
for (const callback of this._callbacks.values())
callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
this._callbacks.clear();
this.emit(Events.Connection.Disconnected);
}
dispose() {
this._onClose();
this._transport.close();
}
}
/**
* @param {!Error} error
* @param {string} method
* @param {{error: {message: string, data: any}}} object
* @return {!Error}
*/
function createProtocolError(error, method, object) {
let message = `Protocol error (${method}): ${object.error.message}`;
if ('data' in object.error)
message += ` ${object.error.data}`;
return rewriteError(error, message);
}
/**
* @param {!Error} error
* @param {string} message
* @return {!Error}
*/
function rewriteError(error, message) {
error.message = message;
return error;
}
module.exports = {Connection};