What is the proper way to detect a dropped connection in Go?

huangapple
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英文:

What is the proper way to detect a dropped connection in Go?

问题

我正在使用一个Go HTTP服务器实现，该服务器从移动客户端读取上传的内容。然而，我遇到了一个问题，由于长时间的keep-alive，如果移动客户端离线（经常发生），服务器将在读取请求缓冲区时挂起很长时间。

检测到连接断开并关闭输入缓冲区的正确方法是什么？

英文:

I am working with a Go HTTP server implementation that reads an upload from a mobile client. However, I'm experiencing problems where because of a long keep-alive, the server will hang reading the request buffer for quite a long time if the mobile client goes offline (as often happens).

What is the proper way to detect a dropped connection and close the input buffer?

答案1

得分: 2

在服务器上设置一个合理的超时时间，例如：

  1. srv := &http.Server{
  2.     Addr:         ":443",
  3.     ReadTimeout:  time.Minute * 2,
  4.     WriteTimeout: time.Minute * 2,
  5. }
  6. log.Fatal(srv.ListenAndServeTLS(certFile, keyFile))
英文:

Set a reasonable timeout on the server, for example:

  1. srv := &http.Server{
  2.     Addr: ":443",
  3.     ReadTimeout: time.Minute * 2,
  4.     WriteTimeout: time.Minute * 2,
  5. }
  6. log.Fatal(srv.ListenAndServeTLS(certFile, keyFile))

答案2

得分: 1

因为我只想在写入停止时断开连接（并且快速断开，以便我可以记录到目前为止接收到的数据并允许客户端恢复），所以ReadTimeout对我来说不是正确的解决方案。

我在这个gist中找到了答案。你需要在连接本身上设置读取超时。

  1. package nettimeout
  3. import (
  4. 	"net"
  5. 	"time"
  6. )
  8. // Listener wraps a net.Listener, and gives a place to store the timeout
  9. // parameters. On Accept, it will wrap the net.Conn with our own Conn for us.
  10. type Listener struct {
  11. 	net.Listener
  12. 	ReadTimeout  time.Duration
  13. 	WriteTimeout time.Duration
  14. }
  16. func (l *Listener) Accept() (net.Conn, error) {
  17. 	c, err := l.Listener.Accept()
  18. 	if err != nil {
  19. 		return nil, err
  20. 	}
  21. 	tc := &Conn{
  22. 		Conn:         c,
  23. 		ReadTimeout:  l.ReadTimeout,
  24. 		WriteTimeout: l.WriteTimeout,
  25. 	}
  26. 	return tc, nil
  27. }
  29. // Conn wraps a net.Conn, and sets a deadline for every read
  30. // and write operation.
  31. type Conn struct {
  32. 	net.Conn
  33. 	ReadTimeout  time.Duration
  34. 	WriteTimeout time.Duration
  35. }
  37. func (c *Conn) Read(b []byte) (int, error) {
  38. 	err := c.Conn.SetReadDeadline(time.Now().Add(c.ReadTimeout))
  39. 	if err != nil {
  40. 		return 0, err
  41. 	}
  42. 	return c.Conn.Read(b)
  43. }
  45. func (c *Conn) Write(b []byte) (int, error) {
  46. 	err := c.Conn.SetWriteDeadline(time.Now().Add(c.WriteTimeout))
  47. 	if err != nil {
  48. 		return 0, err
  49. 	}
  50. 	return c.Conn.Write(b)
  51. }
  53. func NewListener(addr string, readTimeout, writeTimeout time.Duration) (net.Listener, error) {
  54. 	l, err := net.Listen("tcp", addr)
  55. 	if err != nil {
  56. 		return nil, err
  57. 	}
  59. 	tl := &Listener{
  60. 		Listener:     l,
  61. 		ReadTimeout:  readTimeout,
  62. 		WriteTimeout: writeTimeout,
  63. 	}
  64. 	return tl, nil
  65. }
英文:

Because I wanted to drop the connection only when writes stop (and quickly, so that I can record the data received so far and allow the client to resume), the ReadTimeout isn't the right solution for me.

I found the answer in this gist. You need to set a read on the connection itself.

package nettimeout

  1. import (
  2. "net"
  3. "time"
  4. )
  5. // Listener wraps a net.Listener, and gives a place to store the timeout
  6. // parameters. On Accept, it will wrap the net.Conn with our own Conn for us.
  7. type Listener struct {
  8. net.Listener
  9. ReadTimeout  time.Duration
  10. WriteTimeout time.Duration
  11. }
  12. func (l *Listener) Accept() (net.Conn, error) {
  13. c, err := l.Listener.Accept()
  14. if err != nil {
  15. return nil, err
  16. }
  17. tc := &Conn{
  18. Conn:         c,
  19. ReadTimeout:  l.ReadTimeout,
  20. WriteTimeout: l.WriteTimeout,
  21. }
  22. return tc, nil
  23. }
  24. // Conn wraps a net.Conn, and sets a deadline for every read
  25. // and write operation.
  26. type Conn struct {
  27. net.Conn
  28. ReadTimeout  time.Duration
  29. WriteTimeout time.Duration
  30. }
  31. func (c *Conn) Read(b []byte) (int, error) {
  32. err := c.Conn.SetReadDeadline(time.Now().Add(c.ReadTimeout))
  33. if err != nil {
  34. return 0, err
  35. }
  36. return c.Conn.Read(b)
  37. }
  38. func (c *Conn) Write(b []byte) (int, error) {
  39. err := c.Conn.SetWriteDeadline(time.Now().Add(c.WriteTimeout))
  40. if err != nil {
  41. return 0, err
  42. }
  43. return c.Conn.Write(b)
  44. }
  45. func NewListener(addr string, readTimeout, writeTimeout time.Duration) (net.Listener, error) {
  46. l, err := net.Listen("tcp", addr)
  47. if err != nil {
  48. return nil, err
  49. }
  50. tl := &Listener{
  51. Listener:     l,
  52. ReadTimeout:  readTimeout,
  53. WriteTimeout: writeTimeout,
  54. }
  55. return tl, nil
  56. }

huangapple
  • 本文由 发表于 2016年4月22日 06:44:58
  • 转载请务必保留本文链接：https://go.coder-hub.com/36781707.html
  • go
  • http
  • server
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