HTML5的TCP和UDP Web Socket API草案定稿

http://ourjs.com/detail/54810f3e0dad0fbb6d000012

分类 技术前沿 关键字 Html5 发布 kris 2014-12-05

注意 转载须保留原文链接，译文链接，作者译者等信息。

这是在Web上实现UDP/TCP API的草案，沿未形成标准。该标准的一大亮点就是使用内置Promise设计模式，替代了传统JavaScript中的事件触发回调。不过各大浏览器厂商会不会这样实现还要打一个问号，毕竟编写标准的学院派和实现标准的行业派很难达到完全统一。

以下内容来自： http://www.w3.org/TR/2014/WD-tcp-udp-sockets-20141202/

接口标准提供对原始UDP套接字(Socket)，TCP客户端套接字和TCP服务器套接字API的定义。

简介

这部分沿未形成规范。您可以使用该API来发送和接收数据，并使用TCP或UDP网络。

使用此API的部分用例：

能够与SMTP, POP3 和 IMAP 服务器进行通信的邮件服务器。
一个能与IRC服务器进行通信的IRC客户端 （注* IRC是一种通过网络的即时聊天方式。其主要用于群组聊天。）
实现一个SSH应用程序
与现有的消费硬件产品进行通信，如互联网电视
游戏服务器
端到端应用程序（注* P2P或对等网络应用）
本地网络多播服务（multicast service）发掘，例如UPnP/ SSDP和mDNS

一个UDP的例子：

//
// This example shows a simple implementation of UPnP-SSDP M-SEARCH
// discovery using a multicast UDPSocket
//

var address = '239.255.255.250',
port = '1900',
serviceType = 'upnp:rootdevice',
rn = '\r\n',
search = '';

//  Create a new UDP client socket
var mySocket = new UDPSocket();

// Build an SSDP M-SEARCH multicast message
search += 'M-SEARCH * HTTP/1.1' + rn;
search += 'ST: ' + serviceType + rn;
search += 'MAN: "ssdp:discover"' + rn;
search += 'HOST: ' + address + ':' + port + rn;
search += 'MX: 10';

// Receive and log SSDP M-SEARCH response messages
function receiveMSearchResponses() {

// While data in buffer, read and log UDP message
while (mySocket.readable.state === "readable") {
var msg = mySocket.readable.read();
console.log ('Remote address: ' + msg.remoteAddress +
' Remote port: ' + msg.remotePort +
'Message: ' + ab2str(msg.data));
// ArrayBuffer to string conversion could also be done by piping
// through a transform stream. To be updated when the Streams API
// specification has been stabilized on this point.
}

// Wait for SSDP M-SEARCH responses to arrive
mySocket.readable.wait().then(
receiveMSearchResponses,
e => console.error("Receiving error: ", e);
);
}

// Join SSDP multicast group
mySocket.joinMulticast(address);

// Send SSDP M-SEARCH multicast message
mySocket.writeable.write(
{data : str2ab(search),
remoteAddress : address,
remotePort : port
}).then(
() => {
// Data sent sucessfully, wait for response
console.log('M-SEARCH Sent');
receiveMSearchResponses();
},
e => console.error("Sending error: ", e);
);

// Log result of UDP socket setup.
mySocket.opened.then(
() => {
console.log("UDP socket created sucessfully");
},
e =>console.error("UDP socket setup failed due to error: ", e);
);

// Handle UDP socket closed, either as a result of the application
// calling mySocket.close() or an error causing the socket to be
closed.
mySocket.closed.then(
() => {
console.log("Socket has been cleanly closed");
},
e => console.error("Socket closed due to error: ", e);
);

相比UDP，TCP的示例代码显得简单一些

//
// This example shows a simple TCP echo client.
// The client will send "Hello World" to the server on port 6789 and log
// what has been received from the server.
//

//  Create a new TCP client socket and connect to remote host
var mySocket = new TCPSocket("127.0.0.1", 6789);

// Send data to server
mySocket.writeable.write("Hello World").then(
() => {

// Data sent sucessfully, wait for response
console.log("Data has been sent to server");
mySocket.readable.wait().then(
() => {

// Data in buffer, read it
console.log("Data received from server:" + mySocket.readable.read());

// Close the TCP connection
mySocket.close();
},

e => console.error("Receiving error: ", e);
);
},
e => console.error("Sending error: ", e);
);

// Signal that we won't be writing any more and can close the write half of the connection.
mySocket.halfClose();

// Log result of TCP connection attempt.
mySocket.opened.then(
() => {
console.log("TCP connection established sucessfully");
},
e =>console.error("TCP connection setup failed due to error: ", e);
);

// Handle TCP connection closed, either as a result of the application
// calling mySocket.close() or the other side closed the TCP
// connection or an error causing the TCP connection to be closed.
mySocket.closed.then(
() => {
console.log("TCP socket has been cleanly closed");
},
e => console.error("TCP socket closed due to error: ", e);
);

有什么问题可在Github上面给他们开Issues:， 不过关注者廖廖（14个star目前）： https://github.com/sysapps/tcp-udp-sockets/issues