在Go中的服务器，重定向到标准输出

huangapple
go评论120阅读模式
英文:

Server in Go, redirection to stdout

问题

如何在Go中实现一个服务器，将每个传入的行发送到标准输出？

  1. package main
  3. import (
  4.     "io"
  5.     "log"
  6.     "net"
  7.     "bufio"
  8. )
  10. func main() {
  11.     srv, err := net.Listen("tcp", ":2000")
  12.     if err != nil {
  13.         log.Fatal(err)
  14.     }
  15.     for {
  16.         conn, err := srv.Accept()
  17.         if err != nil {
  18.             log.Fatal(err)
  19.         }
  20.         go func(c net.Conn) {
  21.             defer c.Close()
  22.             reader := bufio.NewReader(c)
  23.             for {
  24.                 line, err := reader.ReadString('\n')
  25.                 if err != nil {
  26.                     if err == io.EOF {
  27.                         break
  28.                     }
  29.                     log.Println(err)
  30.                     break
  31.                 }
  32.                 log.Println(line)
  33.             }
  34.         }(conn)
  35.     }
  36. }
英文:

How I can implement a server in Go, which sends each incomming line to stdout ?

  1. package main
  3. import (
  4. 	"io"
  5. 	"log"
  6. 	"net"
  7. )
  9. func main() {
  10. 	srv, err := net.Listen("tcp", ":2000")
  11. 	for {
  12. 		conn, err := srv.Accept()
  13. 		go func(c net.Conn) {
  14.             
  15.             //How to split here by lines ?
  17. 			c.Close()
  18. 		}(conn)
  19. 	}
  20. }

After runing the server with

  1. ./server

And running telnet

  1. telnet localhost 2000
  2. Trying 127.0.0.1...
  3. Connected to localhost.
  4. Escape character is '^]'.
  5. test 123
  6. foobar

I want to see on stdout where I started the server:

  1. test 123
  2. foobar

I know this code lacks error handling, but this is only for clearity to show what I'm trying to do.

答案1

得分: 7

由于net.Conn是一个io.Reader，您可以将其包装在一个bufio.Reader中，并在该类型上使用ReadString方法。您的函数将变为

  1. func(c net.Conn) {
  2.     f := bufio.NewReader(c)
  3.     for {
  4.         ln, err := f.ReadString('\n')
  5.         if err == io.EOF {
  6.             break
  7.         } else if err != nil {
  8.             panic(err)
  9.         }
  10.         fmt.Print(ln)
  11.     }
  12.     c.Close()
  13. }

（我不确定Go中的stdout是否同步；在一个单独的goroutine中循环遍历共享通道上的行可能更清晰。）

英文:

Since a net.Conn is an io.Reader, you can wrap it in a bufio.Reader and use the ReadString method on that type. Your function would become

  1. func(c net.Conn) {
  2.     f := bufio.NewReader(c)
  3.     for {
  4.         ln, err := f.ReadString('\n')
  5.         if err == io.EOF {
  6.             break
  7.         } else if err != nil {
  8.             panic(err)
  9.         }
  10.         fmt.Print(ln)
  11.     }
  12.     c.Close()
  13. }

(I'm not sure if stdout is synchronized in Go; it might be cleaner to send the lines on a shared channel that is looped over in a separate goroutine.)

答案2

得分: 5

如果这是你想要的全部，只需将套接字复制到标准输出。

  1. package main
  3. import (
  4. 	"io"
  5. 	"log"
  6. 	"net"
  7. 	"os"
  8. )
  10. func main() {
  11. 	srv, err := net.Listen("tcp", ":2000")
  12. 	if err != nil {
  13. 		log.Fatalf("Error listening: %v", err)
  14. 	}
  15. 	for {
  16. 		conn, err := srv.Accept()
  17. 		if err != nil {
  18. 			log.Fatalf("Error accepting: %v", err)
  19. 		}
  20. 		go func(c net.Conn) {
  21. 			defer c.Close()
  22. 			io.Copy(os.Stdout, c)
  23. 		}(conn)
  24. 	}
  25. }
英文:

If that's all you want, just copy the socket to stdout.

  1. package main
  3. import (
  4. 	"io"
  5. 	"log"
  6. 	"net"
  7. 	"os"
  8. )
  10. func main() {
  11. 	srv, err := net.Listen("tcp", ":2000")
  12. 	if err != nil {
  13. 		log.Fatalf("Error listening: %v", err)
  14. 	}
  15. 	for {
  16. 		conn, err := srv.Accept()
  17. 		if err != nil {
  18. 			log.Fatalf("Error accepting: %v", err)
  19. 		}
  20. 		go func(c net.Conn) {
  21. 			defer c.Close()
  22. 			io.Copy(os.Stdout, c)
  23. 		}(conn)
  24. 	}
  25. }

huangapple
  • 本文由 发表于 2012年12月29日 21:17:56
  • 转载请务必保留本文链接：https://go.coder-hub.com/14082063.html
  • go
  • networking
  • tcp
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