/*
* Cettia
* http://cettia.io/projects/cettia-protocol/
*
* Copyright 2015 the original author or authors.
* Licensed under the Apache License, Version 2.0
* http://www.apache.org/licenses/LICENSE-2.0
*/
var events = require("events");
var url = require("url");
var WebSocket = require("ws");
var createBaseTransport = require("./transport-base-transport");This function is exposed to the module’s transport module’s createWebSocketTransport as a
factory to create a WebSocket transport. WebSocket is a protocol designed for a full-duplex
communications over a TCP connection.
module.exports = function(uri, options) {
var urlObj = url.parse(uri, true);URI’s protocol should be either ws or wss.
if (urlObj.protocol === "ws:" || urlObj.protocol === "wss:") {A transport object.
var self = createBaseTransport(uri, options);
var ws;
self.connect = function() {Adds a trailing slash to authority if query is not empty. https://github.com/websockets/ws/issues/258
uri = uri.replace(/([^\/])\?/, "$1\/\?");Simply delegates WebSocket’s events to transport and transport’s behaviors to WebSocket.
ws = new WebSocket(uri);
ws.onopen = function() {
self.emit("open");
};
ws.onmessage = function(event) {event.data is a message. It is string if text frame is sent and Buffer if binary
frame is sent.
if (typeof event.data === "string") {
self.emit("text", event.data);
} else {
self.emit("binary", event.data);
}
};
ws.onerror = function(error) {
self.emit("error", error);A transport should fire close event as well as error event when a connection fails.
https://github.com/websockets/ws/issues/505
if (ws.readyState === WebSocket.CONNECTING && error.code === "ECONNREFUSED") {
self.emit("close");
}
};
ws.onclose = function() {
self.emit("close");
};
};
self.write = function(data) {If data is string, a text frame is sent, and if it’s Buffer, a binary frame is sent.
ws.send(data);
};
self.close = function() {
ws.close();
return this;
};
return self;
}
};