NET包中TCP连接是怎么关闭的? [英] How to know TCP connection is closed in net package?

问题描述

我正在实现一个小型TCP服务器.我怎么知道我的一位客户是否关门?我是否应该尝试读取或写入并检查err是否为零?

I'm implementing a small TCP server. How do I know if one of my clients closed? Should I just try to read or write and check if err is nil?

推荐答案

该线程"c使用net.Conn(另请参见 utils/ping.go 或许多其他实例):

That thread "Best way to reliably detect that a TCP connection is closed", using net.Conn for 'c' (also seen in utils/ping.go or locale-backend/server.go or many other instances):

one := make([]byte, 1)
c.SetReadDeadline(time.Now())
if _, err := c.Read(one); err == io.EOF {
  l.Printf(logger.LevelDebug, "%s detected closed LAN connection", id)
  c.Close()
  c = nil
} else {
  var zero time.Time
  c.SetReadDeadline(time.Now().Add(10 * time.Millisecond))
}

要检测超时，建议:

if neterr, ok := err.(net.Error); ok && neterr.Timeout() {
  ...

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更新2019: tuxedo25 提到

---

Update 2019: tuxedo25 mentions in the comments:

在1.7+中，零字节读取立即返回，并且永远不会返回错误.
您必须至少读取一个字节.

In go 1.7+, zero byte reads return immediately and will never return an error.
You must read at least one byte.

请参见提交5bcdd63 和

net:不要从零字节读取中返回io.EOF

net: don't return io.EOF from zero byte reads

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