Client/Server Code : Implementing multiple client handling

[Abhinav Srivastava]

Hi,

I am new to golang and wanted to learn to create client server in Golang. So, I referred to one blog and found the simple client server to understand. Here is the code from the github of ER Technology Ltd with certain modifications:

Server :

package main

import (

"fmt";

"net";

"os";

)

func main() {

var (

host = "127.0.0.1";

port = "9001";

remote = host + ":" + port;

data = make([]byte, 1024);

)

fmt.Println("Initiating server... (Ctrl-C to stop)");

lis, error := net.Listen("tcp", remote);

defer lis.Close();

if error != nil {

fmt.Printf("Error creating listener: %s\n", error );

os.Exit(1);

}

for {

var response string;

var read = true;

con, error := lis.Accept();

if error != nil { fmt.Printf("Error: Accepting data: %s\n", error); os.Exit(2); }

fmt.Printf("=== New Connection received from: %s \n", con.RemoteAddr());

for read {

n, error := con.Read(data);

if error== nil{

//fmt.Println(string(data[0:n])); // Debug

response = response + string(data[0:n]);

}else{

fmt.Printf("Reading data : done\n", );

read = false;

}

}

fmt.Println("Data send by client: " + response);

con.Close();

}

}

Client :

package main

import (

"fmt";

"net";

"os";

)

func main() {

var (

host = "127.0.0.1";

port = "9001";

remote = host + ":" + port;

   msg string=""

)

var inp string

con, error := net.Dial("tcp",remote);

defer con.Close();

if error != nil { fmt.Printf("Host not found: %s\n", error ); os.Exit(1); }

for inp!="quit" {

   fmt.Scanf("%s",&inp);

   msg+=inp;

}

in, error := con.Write([]byte(msg));

if error != nil { fmt.Printf("Error sending data: %s, in: %d\n", error, in ); os.Exit(2); }

fmt.Println("Connection OK");

}

what i was trying to do in client  is as soon as user inputs something on console , same is send to the server. So, i did like this :

for inp!="quit" {

    fmt.Scanf("%s",&inp);

_, error := con.Write([]byte(inp));

         if error != nil {

    //to handle errors   

    }

}

But then, it was not sending anything to the server. But don't know why. Write is suppose to write to the server through con object.

Please guide me.

Also , if I want to handle mutiple clients , should the server be using go rountines, if yes , then how.

Thanks for the help.

Regards

Abhinav

[Tamás Gulácsi]

Maybe not the cause, but do not use error as a variable name, as that is a builti interface already.

Try printing out what you are sending before the send in the client inner loop - fmt.Scanf requires separaor at the end (space or newline).