Sending message from a Java socket to a PHP server socket

Question

I have a socket listening to a certain port in PHP, and I am trying to send a string using a socket in Java, but I keep getting the following error:

Warning: socket_recv(): unable to read from socket [0]: The operation completed successfully.
 in H:\Dropbox\EISTI\www\java-instagram-web\src\Client\Component\Server\Client.php on line 55

Without any more description, it is hard to understand what is the problem.

My PHP class looks like the following:

class Client {
    private $address;
    private $port;
    private $command;

    public function __construct($port, $address, $addressServer, $portServer, $command)
    {
        set_time_limit(0);
        $this->address = $address;
        $this->port = $port;
        $this->init();
    }

    private function init(){

        //Create socket
        if (! $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) {
            $this->showError('socket create');
        }
        echo "Server Created\n";

        //Bind socket
        if (!socket_bind($socket, $this->address, $this->port)) {
            $this->showError('socket bind');
        }
        echo "Server bind to $this->address and $this->port \n";

        if (!socket_listen($socket)) {
            $this->showError('socket listen');
        }
        echo "Server Listening \n";

        do {
            $client = socket_accept($socket);
            echo "connection established\n";

            $message = "\n Hey! welcome to the server\n";
            socket_write($client, $message, strlen($message));

            do {
                if (! socket_recv($socket, $clientMessage, 2045, MSG_WAITALL)) {
                    $this->showError('socket receive');
                }
                $message = "Command Received\n";
                echo $clientMessage;

                socket_send($client, $message, strlen($message), 0);

                if (!$clientMessage = trim($clientMessage)) {
                    continue;
                }

                if (trim($clientMessage) == 'close') {
                    socket_close($client);
                    echo "\n\n--------------------------------------------\n".
                        "ClientRequest terminated\n";
                    break 1;
                }
            } while(true);

        } while(true);
    }

    private function showError($message) {
        echo ("Error: ".$message);
        exit(666);
    }
}

And my Java socket class looks like the following:

public class ResponseToClient {
    private String host;
    private int port;
    private Socket socket;
    private PrintStream theOut;
    private String resultLocation;

    /**
     * Constructor
     */
    public ResponseToClient(String path) {
        this.host = "localhost";
        this.port = 1000;
        this.resultLocation = path;
    }

    /**
     * Setting up Socket
     */
    public void init(){
        try{

            socket = new Socket(host, port);
            theOut = new PrintStream(socket.getOutputStream());

            //Send Command
            sendCommand();

            //Closing connections
            socket.close();
            theOut.close();

        }
        catch (IOException e){
            e.printStackTrace();
        }
    }

    /**
     * Send Command
     */
    public void sendCommand()
    {
        theOut.println(Messages.type_response + Messages.seperator_client + resultLocation);
        System.out.println(Messages.type_response + Messages.seperator_client + resultLocation);
    }
}

What am I doing wrong?

You might checkout this question with a similar issue. stackoverflow.com/a/11610618/2863 — Scott Gottreu
– Scott Gottreu, Commented Apr 15, 2015 at 20:15

RealSkeptic · Accepted Answer · 2015-04-15 20:51:00Z

1

I believe the problem is that you are trying to read from your server socket on the PHP side, rather than your client socket:

socket_recv($socket, $clientMessage, 2045, MSG_WAITALL)

This should be

socket_recv($client, $clientMessage, 2045, MSG_WAITALL)

answered Apr 15, 2015 at 20:51

RealSkeptic

34.8k7 gold badges56 silver badges83 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Codious-JR Over a year ago

ah you are right. Nevermind, i didn't realize i made that change while re-writing the code.

Codious-JR · Accepted Answer · 2015-04-19 12:38:01Z

I figured out the problem.

There were two problems, I was reading from the wrong socket, So i made the change as suggested by @RealSkeptic, changing from :

socket_recv($socket, $clientMessage, 2045, MSG_WAITALL)

To

socket_recv($client, $clientMessage, 2045, MSG_WAITALL)

And Another Problem was the inner while loop that I was using was which was en-globing the socket_read.

I did it this way, because I had got this code off a tutorial I found for server_sockets in PHP.

But it created a problem here because of the flow of the communication:

Answer:

On the Java side I was sending only one single response, whereas on the PHP side I was using socket_read "infinitely" in the while loop until I received the string "close". This was creating the problem because, after receiving the first response, there is nothing else to read. Thus the error.

So to solve the problem I just had to remove the while loop, (and I removed the socket_write as for my purpose I do not need to send any information).

The working example for the class Client:

class Client {

    private $addressServer;
    private $portServer;
    private $address;
    private $port;
    private $command;

    public function __construct($port, $address, $addressServer, $portServer, $command)
    {
        set_time_limit(0);
        $this->addressServer = $addressServer;
        $this->address = $address;
        $this->portServer = $portServer;
        $this->port = $port;
        $this->command = $command;
        $this->init();
    }

    private function init() {

        //Send request to the Java server
        $request = new Request(
            $this->addressServer, $this->portServer, $this->command
        );

        //create socket
        if (! $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) {
            $this->showError('socket create');
        }
        echo "Server Created\n";

        //Bind socket
        if (!socket_bind($socket, $this->address, $this->port)) {
            $this->showError('socket bind');
        }
        echo "Server bind to $this->address and $this->port \n";

        if (!socket_listen($socket)) {
            $this->showError('socket listen');
        }
        echo "Server Listening \n";

        do {
            $client = socket_accept($socket);
            echo "connection established\n";

            if(!$clientMessage = socket_read($client, 10000, PHP_NORMAL_READ)){
                $this->showError('socket read');
            }

            echo "Command Received\n";
            echo $clientMessage;

        } while(true);
    }

    private function showError($message){
        echo ("Error: ".$message);
        exit(666);
    }
}

Collectives™ on Stack Overflow

Sending message from a Java socket to a PHP server socket

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related