socket.connect(options[, connectListener])


在给定的套接字上发起连接。 一般不需要这个方法,套接字应该用 net.createConnection() 创建和打开。 仅在实现自定义套接字时使用它。

对于 TCP 连接,可用的 options 是:

  • port <number> 必需的。 套接字应连接到的端口。
  • host <string> 套接字应连接到的主机。 默认值: 'localhost'
  • localAddress <string> 套接字应该连接的本地地址。
  • localPort <number> 套接字应连接的本地端口。
  • family <number>: IP 堆栈的版本。 必须是 460。 值 0 表示允许 IPv4 和 IPv6 地址。 默认值: 0
  • hints <number> 可选的 dns.lookup() 提示
  • lookup <Function> 自定义查找函数。 默认值: dns.lookup().
  • noDelay <boolean> 如果设置为 true,则它会在套接字建立后立即禁用 Nagle 算法。 默认值: false
  • keepAlive <boolean> 如果设置为 true,则它会在连接建立后立即在套接字上启用保持活动功能,类似于在 socket.setKeepAlive([enable][, initialDelay]) 中所做的。 默认值: false
  • keepAliveInitialDelay <number> 如果设置为正数,则它会设置在空闲套接字上发送第一个保持活跃探测之前的初始延迟。默认值: 0

对于 IPC 连接,可用的 options 是:

对于这两种类型,可用的 options 包括:

  • onread <Object> 如果指定,传入的数据存储在单个 buffer 中,并在数据到达套接字时传给提供的 callback。 这将导致流功能不提供任何数据。 套接字将像往常一样触发 'error''end''close' 等事件。 pause()resume() 等方法也将按预期运行。
    • buffer <Buffer> | <Uint8Array> | <Function> 用于存储传入数据的可重用内存块或返回此类数据的函数。
    • callback <Function> 为每个传入数据块调用此函数。 传给它的有两个参数:写入 buffer 的字节数和对 buffer 的引用。 从此函数返回 false 以隐式 pause() 套接字。 该函数将在全局上下文中执行。

以下是使用 onread 选项的客户端示例:

const net = require('node:net');
net.connect({
  port: 80,
  onread: {
    // 每次从套接字读取时重用 4KiB 缓冲区。
    buffer: Buffer.alloc(4 * 1024),
    callback: function(nread, buf) {
      // 接收到的数据在 `buf` 中可用,从 0 到 `nread`。
      console.log(buf.toString('utf8', 0, nread));
    }
  }
});

Initiate a connection on a given socket. Normally this method is not needed, the socket should be created and opened with net.createConnection(). Use this only when implementing a custom Socket.

For TCP connections, available options are:

  • port <number> Required. Port the socket should connect to.
  • host <string> Host the socket should connect to. Default: 'localhost'.
  • localAddress <string> Local address the socket should connect from.
  • localPort <number> Local port the socket should connect from.
  • family <number>: Version of IP stack. Must be 4, 6, or 0. The value 0 indicates that both IPv4 and IPv6 addresses are allowed. Default: 0.
  • hints <number> Optional dns.lookup() hints.
  • lookup <Function> Custom lookup function. Default: dns.lookup().
  • noDelay <boolean> If set to true, it disables the use of Nagle's algorithm immediately after the socket is established. Default: false.
  • keepAlive <boolean> If set to true, it enables keep-alive functionality on the socket immediately after the connection is established, similarly on what is done in socket.setKeepAlive([enable][, initialDelay]). Default: false.
  • keepAliveInitialDelay <number> If set to a positive number, it sets the initial delay before the first keepalive probe is sent on an idle socket.Default: 0.

For IPC connections, available options are:

For both types, available options include:

  • onread <Object> If specified, incoming data is stored in a single buffer and passed to the supplied callback when data arrives on the socket. This will cause the streaming functionality to not provide any data. The socket will emit events like 'error', 'end', and 'close' as usual. Methods like pause() and resume() will also behave as expected.
    • buffer <Buffer> | <Uint8Array> | <Function> Either a reusable chunk of memory to use for storing incoming data or a function that returns such.
    • callback <Function> This function is called for every chunk of incoming data. Two arguments are passed to it: the number of bytes written to buffer and a reference to buffer. Return false from this function to implicitly pause() the socket. This function will be executed in the global context.

Following is an example of a client using the onread option:

const net = require('node:net');
net.connect({
  port: 80,
  onread: {
    // Reuses a 4KiB Buffer for every read from the socket.
    buffer: Buffer.alloc(4 * 1024),
    callback: function(nread, buf) {
      // Received data is available in `buf` from 0 to `nread`.
      console.log(buf.toString('utf8', 0, nread));
    }
  }
});