PHP/Go socket communication

Im trying to communicate between Go and PHP with a socket. The code im using is:

Go:

fmt.Println("Launching server...")
ln, _ := net.Listen("tcp", ":8080")
conn, _ := ln.Accept()

for {
	message, _ := bufio.NewReader(conn).ReadString('\n')
	fmt.Print("Message Received:", string(message))
	conn.Write([]byte("test" +"\n"))
	
}

PHP:

$address = gethostbyaddr($ip);
	$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
	if($socket === false){
		echo "socket_create() failed: reason: " . socket_strerror(socket_last_error());
	}

	$result = socket_connect($socket, $address, $port);
	if ($result === false) {
	    echo "socket_connect() failed.\nReason: ($result) " . socket_strerror(socket_last_error($socket));
	} 
    socket_write($socket, "test", 4);
    socket_read($socket, 4);

The problem is that the Go server keeps thinking it's receiving something all the time so it prints "Message Recieved:" constantly. If i do if(message!="") it sort of works but the cpu usage is high.

Another problem is that the server doesn't receive "test" unless i comment out the socket_read($socket, 4); in PHP.

The documentation for ReadString says:

> If ReadString encounters an error before finding a delimiter, it returns the data read before the error and the error itself (often io.EOF).

This means that you're getting io.EOF (indicating that there's no more data to be read from the connection) and an empty string.

If you want to block on ReadString when no data is available, don't use bufio but rather read directly from the connection.

See also: documentation for net.Conn

> Another problem is that the server doesn't receive "test" unless i comment out the socket_read($socket, 4); in PHP.

That's described here, socket_write buffers:

> socket_write() does not necessarily write all bytes from the given buffer. [...]

use

fflush($socket);

after the write.