socket.bind([port][, address][, callback])
port
<integer>address
<string>callback
<Function> 没有参数。 当绑定完成时调用。
对于 UDP 套接字,使 dgram.Socket
在命名的 port
和可选的 address
上监听数据报消息。
如果未指定 port
或 0
,则操作系统将尝试绑定到随机端口。
如果未指定 address
,则操作系统将尝试监听所有地址。
一旦绑定完成,则会触发 'listening'
事件并调用可选的 callback
函数。
同时指定 'listening'
事件监听器并将 callback
传给 socket.bind()
方法无害但不是很有用。
绑定的数据报套接字使 Node.js 进程保持运行以接收数据报消息。
如果绑定失败,则生成 'error'
事件。
在极少数情况下(例如,尝试与关闭的套接字绑定),可能会抛出 Error
。
UDP 服务器监听端口 41234 的示例:
const dgram = require('dgram');
const server = dgram.createSocket('udp4');
server.on('error', (err) => {
console.log(`server error:\n${err.stack}`);
server.close();
});
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
server.on('listening', () => {
const address = server.address();
console.log(`server listening ${address.address}:${address.port}`);
});
server.bind(41234);
// 打印: server listening 0.0.0.0:41234
port
<integer>address
<string>callback
<Function> with no parameters. Called when binding is complete.
For UDP sockets, causes the dgram.Socket
to listen for datagram
messages on a named port
and optional address
. If port
is not
specified or is 0
, the operating system will attempt to bind to a
random port. If address
is not specified, the operating system will
attempt to listen on all addresses. Once binding is complete, a
'listening'
event is emitted and the optional callback
function is
called.
Specifying both a 'listening'
event listener and passing a
callback
to the socket.bind()
method is not harmful but not very
useful.
A bound datagram socket keeps the Node.js process running to receive datagram messages.
If binding fails, an 'error'
event is generated. In rare case (e.g.
attempting to bind with a closed socket), an Error
may be thrown.
Example of a UDP server listening on port 41234:
const dgram = require('dgram');
const server = dgram.createSocket('udp4');
server.on('error', (err) => {
console.log(`server error:\n${err.stack}`);
server.close();
});
server.on('message', (msg, rinfo) => {
console.log(`server got: ${msg} from ${rinfo.address}:${rinfo.port}`);
});
server.on('listening', () => {
const address = server.address();
console.log(`server listening ${address.address}:${address.port}`);
});
server.bind(41234);
// Prints: server listening 0.0.0.0:41234