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socketsnetwork-programmingtcpgoclient

Creating a TCP client in golang


Hi i'm attempted to learn some socket programming in golang, I'm following along with this tutorial

http://synflood.at/tmp/golang-slides/mrmcd2012.html#1

Here is the final result of the tutorial on one page. https://github.com/akrennmair/telnet-chat/blob/master/03_chat/chat.go

I'm confused on how to write the client side of this program, I create a connection and dial into the same port/ip as the server is running on but from there I don't know. I have read() and write() functions for the newly created connection but no idea where to delimit the read or anything. Considering the text input is handeled in the server I imagine I'd only need to do a read of some kind?

package main

import (
    "bufio"
    "fmt"
    "net"
    "os"
)

func main() {
    conn, err := net.Dial("tcp", "127.0.0.1:6000")
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }

    for {
        fmt.Println(bufio.NewReader(conn).ReadString([]byte("\n")))
    }

}

Solution

  • bufio.NewReadershould be used only once, in your case, just before the for. For example connbuf := bufio.NewReader(conn). Then you can use ReadString on connbuf, that returns the string and maybe an error. For example:

    connbuf := bufio.NewReader(conn)
    for{
        str, err := connbuf.ReadString('\n')
        if err != nil {
            break
        }
    
        if len(str) > 0 {
            fmt.Println(str)
        }
    }
    

    I'm checking lenand err because ReadString may return data and an error (connection error, connection reset, etc.) so you need to check both.