PHP Socket programming tutorial

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Php and tcp/ip sockets

This is a quick guide/tutorial to learning socket programming in php. Socket programming php is very similar to C. Most functions are similar in names, parameters and output. However unlike C, socket programs written in php would run the same way on any os that has php installed. So the code does not need any platform specific changes (mostly).

To summarise the basics, sockets are the fundamental "things" behind any kind of network communications done by your computer. For example when you type www.google.com in your web browser, it opens a socket and connects to google.com to fetch the page and show it to you. Same with any chat client like gtalk or skype. Any network communication goes through a socket.

Before you begin

This tutorial assumes that you already know php and also how to run php scripts from the commandline/terminal. Php scripts are normally run from inside the browser by placing them in the apache root directory like /var/www. However these commandline programs can be run from any directory. They can be run from browsers as well.

So lets begin with sockets.

Creating a socket

This first thing to do is create a socket. The socket_create function does this.
Here is a code sample :

$sock = socket_create(AF_INET, SOCK_STREAM, 0);

Function socket_create creates a socket and returns a socket descriptor which can be used in other network commands.

The above code will create a socket with the following properties ...

Address Family : AF_INET (this is IP version 4)
Type : SOCK_STREAM (this means connection oriented TCP protocol)
Protocol : 0 [ or IPPROTO_IP This is IP protocol]

Error handling

If any of the socket functions fail then the error information can be retrieved using the socket_last_error and socket_strerror functions.

if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created";

Ok , so you have created a socket successfully. But what next ? Next we shall try to connect to some server using this socket. We can connect to www.google.com

Note

Apart from SOCK_STREAM type of sockets there is another type called SOCK_DGRAM which indicates the UDP protocol. This type of socket is non-connection socket. In this tutorial we shall stick to SOCK_STREAM or TCP sockets.







Connect to a Server

We connect to a remote server on a certain port number. So we need 2 things , IP address and port number to connect to. So you need to know the IP address of the remote server you are connecting to. Here we used the ip address of google.com as a sample. A little later on we shall see how to find out the ip address of a given domain name.

The last thing needed is the connect function. It needs a socket and a sockaddr structure to connect to. Here is a code sample.


if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

if(!socket_connect($sock , '74.125.235.20' , 80))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not connect: [$errorcode] $errormsg \n");
}

echo "Connection established \n";

Run the program

$ php /var/www/socket.php
Socket created
Connection established

It creates a socket and then connects. Try connecting to a port different from port 80 and you should not be able to connect which indicates that the port is not open for connection. This logic can be used to build a port scanner.

OK, so we are now connected. Lets do the next thing , sending some data to the remote server.

Quick Note

The concept of "connections" apply to SOCK_STREAM/TCP type of sockets. Connection means a reliable "stream" of data such that there can be multiple such streams each having communication of its own. Think of this as a pipe which is not interfered by other data.

Other sockets like UDP , ICMP , ARP dont have a concept of "connection". These are non-connection based communication. Which means you keep sending or receiving packets from anybody and everybody.

Sending Data

Function send will simply send data. It needs the socket descriptor , the data to send and its size.
Here is a very simple example of sending some data to google.com ip :

if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

//Connect socket to remote server
if(!socket_connect($sock , '74.125.235.20' , 80))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not connect: [$errorcode] $errormsg \n");
}

echo "Connection established \n";

$message = "GET / HTTP/1.1\r\n\r\n";

//Send the message to the server
if( ! socket_send ( $sock , $message , strlen($message) , 0))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not send data: [$errorcode] $errormsg \n");
}

echo "Message send successfully \n";

In the above example , we first connect to an ip address and then send the string message "GET / HTTP/1.1\r\n\r\n" to it.
The message is actually a http command to fetch the mainpage of a website.

Now that we have send some data , its time to receive a reply from the server. So lets do it.

Note

When sending data to a socket you are basically writing data to that socket. This is similar to writing data to a file. Hence you can also use the write function to send data to a socket. Later in this tutorial we shall use write function to send data.

Receiving Data

Function recv is used to receive data on a socket. In the following example we shall send the same message as the last example and receive a reply from the server.

<?php

if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

//Connect socket to remote server
if(!socket_connect($sock , '74.125.235.20' , 80))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not connect: [$errorcode] $errormsg \n");
}

echo "Connection established \n";

$message = "GET / HTTP/1.1\r\n\r\n";

//Send the message to the server
if( ! socket_send ( $sock , $message , strlen($message) , 0))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not send data: [$errorcode] $errormsg \n");
}

echo "Message send successfully \n";

//Now receive reply from server
if(socket_recv ( $sock , $buf , 2045 , MSG_WAITALL ) === FALSE)
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not receive data: [$errorcode] $errormsg \n");
}

//print the received message
echo $buf;

Here is the output of the above code :


$ php /var/www/socket.php 
Socket created 
Connection established 
Message send successfully 
HTTP/1.1 302 Found
Location: http://www.google.co.in/
Cache-Control: private
Content-Type: text/html; charset=UTF-8
Set-Cookie: expires=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=www.google.com
Set-Cookie: path=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=www.google.com
Set-Cookie: domain=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=www.google.com
Set-Cookie: expires=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=.www.google.com
Set-Cookie: path=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=.www.google.com
Set-Cookie: domain=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=.www.google.com
Set-Cookie: expires=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=google.com
Set-Cookie: path=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=google.com
Set-Cookie: domain=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=google.com
Set-Cookie: expires=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=.google.com
Set-Cookie: path=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=.google.com
Set-Cookie: domain=; expires=Mon, 01-Jan-1990 00:00:00 GMT; path=/; domain=.google.com
Set-Cookie: PREF=ID=3c2e53ffcc387bbb:FF=0:TM=1342766363:LM=1342766364:S=DTuSOuahFqyd6vjp; expires=Sun, 20-Jul-2014 06:39:24 GMT; path=/; domain=.google.com
Set-Cookie: NID=62=HZWk5tBSunVEofFri475wbeCNiChGf_bs7Pz_Z32hfm-B-0M4JRhz-pptjtChOk6lVepLBhOtB2pNHCT5DynobfZaGQaPS5Dh9Rq4YAqt40hExsePHEyA0ECMKjq5KeE; expires=Sat, 19-Jan-2013 06:39:24 GMT; path=/; domain=.google.com; HttpOnly
P3P: CP="This is not a P3P policy! See http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info."
Date: Fri, 20 Jul 2012 06:39:24 GMT
Server: gws
Content-Length: 221
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN

<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="http://www.google.co.in/">here</A>.
</BODY>

We can see what reply was send by the server. It looks something like Html, well IT IS html. Google.com replied with the content of the page we requested. Quite simple!

Now that we have received our reply, its time to close the socket.

Close socket

Function socket_close is used to close the socket.

socket_close($sock);

Thats it.

Lets Revise

So in the above example we learned how to :
1. Create a socket
2. Connect to remote server
3. Send some data
4. Receive a reply

Its useful to know that your web browser also does the same thing when you open www.google.com
This kind of socket activity represents a CLIENT. A client is a system that connects to a remote system to fetch data.

The other kind of socket activity is called a SERVER. A server is a system that uses sockets to receive incoming connections and provide them with data. It is just the opposite of Client. So www.google.com is a server and your web browser is a client. Or more technically www.google.com is a HTTP Server and your web browser is an HTTP client.

Now its time to do some server tasks using sockets. But before we move ahead there are a few side topics that should be covered just incase you need them.

Get IP address of a hostname/domain

When connecting to a remote host , it is necessary to have its IP address. Function gethostbyname is used for this purpose. It takes the domain name as the parameter and returns the ip address.

Quick example

$ip_address = gethostbyname("www.google.com");
// = 173.194.75.104

So the above code can be used to find the ip address of any domain name. Then the ip address can be used to make a connection using a socket.

Server Programming

OK now onto server things. Servers basically do the following :

1. Open a socket
2. Bind to a address(and port).
3. Listen for incoming connections.
4. Accept connections
5. Read/Send

We have already learnt how to open a socket. So the next thing would be to bind it.

Bind a socket

Function bind can be used to bind a socket to a particular address and port. It needs a sockaddr_in structure similar to connect function.

Quick example

if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

// Bind the source address
if( !socket_bind($sock, "127.0.0.1" , 5000) )
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not bind socket : [$errorcode] $errormsg \n");
}

echo "Socket bind OK \n";

Now that bind is done, its time to make the socket listen to connections. We bind a socket to a particular IP address and a certain port number. By doing this we ensure that all incoming data which is directed towards this port number is received by this application.

This makes it obvious that you cannot have 2 sockets bound to the same port. There are exceptions to this rule but we shall look into that in some other article.

Listen for connections

After binding a socket to a port the next thing we need to do is listen for connections. For this we need to put the socket in listening mode. Function socket_listen is used to put the socket in listening mode. Just add the following line after bind.

//listen
socket_listen ($sock , 10)

The second parameter of the function socket_listen is called backlog. It controls the number of incoming connections that are kept "waiting" if the program is already busy. So by specifying 10, it means that if 10 connections are already waiting to be processed, then the 11th connection request shall be rejected. This will be more clear after checking socket_accept.

Now comes the main part of accepting new connections.

Accept connection

Function socket_accept is used for this.


if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

// Bind the source address
if( !socket_bind($sock, "127.0.0.1" , 5000) )
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not bind socket : [$errorcode] $errormsg \n");
}

echo "Socket bind OK \n";

if(!socket_listen ($sock , 10))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not listen on socket : [$errorcode] $errormsg \n");
}

echo "Socket listen OK \n";

echo "Waiting for incoming connections... \n";

//Accept incoming connection - This is a blocking call
$client = socket_accept($sock);
	
//display information about the client who is connected
if(socket_getpeername($client , $address , $port))
{
	echo "Client $address : $port is now connected to us.";
}

socket_close($client);
socket_close($sock);

Output

Run the program. It should show

$ php /var/www/server.php
Socket created
Socket bind OK
Socket listen OK
Waiting for incoming connections...

So now this program is waiting for incoming connections on port 5000. Dont close this program , keep it running.
Now a client can connect to it on this port. We shall use the telnet client for testing this. Open a terminal and type

$ telnet localhost 5000

It will immediately show

$ telnet localhost 5000
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.

And the server output will show

Client 127.0.0.1 : 36689 is now connected to us.

So we can see that the client connected to the server. Try the above steps till you get it working perfect.

Note

The socket_getpeername function is used to get details about the client which is connected to the server via a particular socket.

We accepted an incoming connection but closed it immediately. This was not very productive. There are lots of things that can be done after an incoming connection is established. Afterall the connection was established for the purpose of communication. So lets reply to the client.

Function socket_write can be used to write something to the socket of the incoming connection and the client should see it. Here is an example :


if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

// Bind the source address
if( !socket_bind($sock, "127.0.0.1" , 5000) )
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not bind socket : [$errorcode] $errormsg \n");
}

echo "Socket bind OK \n";

if(!socket_listen ($sock , 10))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not listen on socket : [$errorcode] $errormsg \n");
}

echo "Socket listen OK \n";

echo "Waiting for incoming connections... \n";

//Accept incoming connection - This is a blocking call
$client =  socket_accept($sock);

//display information about the client who is connected
if(socket_getpeername($client , $address , $port))
{
	echo "Client $address : $port is now connected to us. \n";
}

//read data from the incoming socket
$input = socket_read($client, 1024000);

$response = "OK .. $input";

// Display output  back to client
socket_write($client, $response);
socket_close($client);

Run the above code in 1 terminal. And connect to this server using telnet from another terminal and you should see this :

$ telnet localhost 5000
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
happy
OK .. happy
Connection closed by foreign host.

So the client(telnet) received a reply from server.

We can see that the connection is closed immediately after that simply because the server program ends after accepting and sending reply. A server like www.google.com is always up to accept incoming connections.

It means that a server is supposed to be running all the time. Afterall its a server meant to serve. So we need to keep our server RUNNING non-stop. The simplest way to do this is to put the accept in a loop so that it can receive incoming connections all the time.

Live Server

So a live server will be alive always. Lets code this up


if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

// Bind the source address
if( !socket_bind($sock, "127.0.0.1" , 5000) )
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not bind socket : [$errorcode] $errormsg \n");
}

echo "Socket bind OK \n";

if(!socket_listen ($sock , 10))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not listen on socket : [$errorcode] $errormsg \n");
}

echo "Socket listen OK \n";

echo "Waiting for incoming connections... \n";

//start loop to listen for incoming connections
while (true) 
{
	//Accept incoming connection - This is a blocking call
	$client =  socket_accept($sock);
	
	//display information about the client who is connected
	if(socket_getpeername($client , $address , $port))
	{
		echo "Client $address : $port is now connected to us. \n";
	}
	
	//read data from the incoming socket
	$input = socket_read($client, 1024000);
	
	$response = "OK .. $input";
	
	// Display output  back to client
	socket_write($client, $response);
}

We havent done a lot there. Just put the socket_accept in a loop.

Now run the server program in 1 terminal , and open 3 other terminals.
From each of the 3 terminal do a telnet to the server port.

Each of the telnet terminal would show :

$ telnet localhost 5000
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
happy
OK .. happy
Connection closed by foreign host.

And the server terminal would show

$ php /var/www/server.php
Socket created
Socket bind OK
Socket listen OK
Waiting for incoming connections...
Client 127.0.0.1 : 37119 is now connected to us.
Client 127.0.0.1 : 37122 is now connected to us.
Client 127.0.0.1 : 37123 is now connected to us.

So now the server is running nonstop and the telnet terminals are also connected nonstop. Now close the server program. All telnet terminals would show "Connection closed by foreign host."

Good so far. But still there is not effective communication between the server and the client. The server program accepts connections in a loop and just send them a reply, after that it does nothing with them. Also it is not able to handle more than 1 connection at a time. So now its time to handle the connections , and handle multiple connections together.

Handling Connections

To handle every connection we need a separate handling code to run along with the main server accepting connections. One way to achieve this is using threads. The main server program accepts a connection and creates a new thread to handle communication for the connection, and then the server goes back to accept more connections.
However php does not support threading directly.

Another method is to use the select function. The select function basically 'polls' or observers a set of sockets for certain events like if its readable, or writable or had a problem or not etc.
So the select function can be used to monitor multiple clients and check which client has send a message.

Quick Example


error_reporting(~E_NOTICE);
set_time_limit (0);

$address = "0.0.0.0";
$port = 5000;
$max_clients = 10;

if(!($sock = socket_create(AF_INET, SOCK_STREAM, 0)))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Couldn't create socket: [$errorcode] $errormsg \n");
}

echo "Socket created \n";

// Bind the source address
if( !socket_bind($sock, $address , 5000) )
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not bind socket : [$errorcode] $errormsg \n");
}

echo "Socket bind OK \n";

if(!socket_listen ($sock , 10))
{
	$errorcode = socket_last_error();
    $errormsg = socket_strerror($errorcode);
    
    die("Could not listen on socket : [$errorcode] $errormsg \n");
}

echo "Socket listen OK \n";

echo "Waiting for incoming connections... \n";

//array of client sockets
$client_socks = array();

//array of sockets to read
$read = array();

//start loop to listen for incoming connections and process existing connections
while (true) 
{
	//prepare array of readable client sockets
	$read = array();
	
	//first socket is the master socket
	$read[0] = $sock;
	
	//now add the existing client sockets
    for ($i = 0; $i < $max_clients; $i++)
    {
        if($client_socks[$i] != null)
		{
			$read[$i+1] = $client_socks[$i];
		}
    }
    
	//now call select - blocking call
    if(socket_select($read , $write , $except , null) === false)
	{
		$errorcode = socket_last_error();
		$errormsg = socket_strerror($errorcode);
    
		die("Could not listen on socket : [$errorcode] $errormsg \n");
	}
    
    //if ready contains the master socket, then a new connection has come in
    if (in_array($sock, $read)) 
	{
        for ($i = 0; $i < $max_clients; $i++)
        {
            if ($client_socks[$i] == null) 
			{
                $client_socks[$i] = socket_accept($sock);
                
                //display information about the client who is connected
				if(socket_getpeername($client_socks[$i], $address, $port))
				{
					echo "Client $address : $port is now connected to us. \n";
				}
				
				//Send Welcome message to client
				$message = "Welcome to php socket server version 1.0 \n";
				$message .= "Enter a message and press enter, and i shall reply back \n";
				socket_write($client_socks[$i] , $message);
				break;
            }
        }
    }

    //check each client if they send any data
    for ($i = 0; $i < $max_clients; $i++)
    {
		if (in_array($client_socks[$i] , $read))
		{
			$input = socket_read($client_socks[$i] , 1024);
            
            if ($input == null) 
			{
				//zero length string meaning disconnected, remove and close the socket
				unset($client_socks[$i]);
				socket_close($client_socks[$i]);
            }

            $n = trim($input);

            $output = "OK ... $input";
            
			echo "Sending output to client \n";
			
			//send response to client
			socket_write($client_socks[$i] , $output);
		}
    }
}

Run the above server and open 3 terminals like before. Now the server will create a thread for each client connecting to it.

The telnet terminals would show :

$ telnet localhost 5000
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
Welcome to php socket server version 1.0 
Enter a message and press enter, and i shall reply back 
hello
OK ... hello
how are you
OK ... how are you

The server terminal might look like this

$ php /var/www/server.php 
Socket created 
Socket bind OK 
Socket listen OK 
Waiting for incoming connections... 
Client 127.0.0.1 : 36259 is now connected to us. 
Sending output to client 
Sending output to client 
Client 127.0.0.1 : 36274 is now connected to us. 
Sending output to client 
Sending output to client 
Client 127.0.0.1 : 36276 is now connected to us. 
Sending output to client 
Sending output to client

The above connection handler takes some input from the client and replies back with the same. Simple! Here is how the telnet output might look

So now we have a server thats communicative. Thats useful now.

Conclusion

By now you must have learned the basics of socket programming in php. You can try out some experiments like writing a chat client or something similar.

If you think that the tutorial needs some addons or improvements or any of the code snippets above dont work then feel free to make a comment below so that it gets fixed.

Last Updated On : 26th March 2013

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About Silver Moon

Php developer, blogger and Linux enthusiast. He can be reached at m00n.silv3r@gmail.com. Or find him on

  • Mohammad Haidar

    I am trying to understand the last example of handling connection but I ca’t, so please could you explain how it works.

  • Phpdev

    I am able to communicate with multiple clients, but i am not able to send data of different clients on same time. Is it possible with this code or not?

  • md5

    Also, one more thing: line 112 isn’t used anywhere, so it can be removed:

    $n = trim($input);

  • md5

    Excellent tutorial :)

    As mentioned already, there’s a bug in your code, lines 108-109:
    unset($client_socks[$i]);
    socket_close($client_socks[$i]);

    When you unset $client_socks[$i], you can no longer call socket_close on it. Thus, these two lines should be swapped:
    socket_close($client_socks[$i]);
    unset($client_socks[$i]);

  • achraf

    can i make a communication between a java socket and a php socket !! thanks

  • Martin Kupec

    Great tutorial and I understand finally a socket issue. Thank you.

  • Anand

    its help me a lot ..i m making a website which will connect the world ..so i need a real time notification and a live chat..so my questions is “with php can i implement this or i should do more?” it will have millions of users
    ..

  • Marmar

    This is a great tutorial! But I have an issue, when I added the while loop, and send anything through telnet, I don’t get a response, it keeps waiting for things to be written on telnet end. Any help will be appreciated.

  • Manee Osman

    It’s works well, but the enter event not working this is my out put and there is also warrnings see bellow:

    Setting environment for using XAMPP for Windows.

    manee.osman@DEV8 c:xampp
    # echo ‘Hello’;
    ‘Hello’;

    manee.osman@DEV8 c:xampp
    # php C:xampphtdocs”JAVASCRIPT PHP TESTS”socket.example.php
    Could not open input file: C:xampphtdocs”JAVASCRIPT

    manee.osman@DEV8 c:xampp
    # php C:xampphtdocsJAVASCRIPT_PHP_TESTSsocket.example.php
    Socket created
    Socket bind OK
    Socket listen OK
    Waiting for incoming connections…
    Client 127.0.0.1 : 37717 is now connected to us.
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Client 127.0.0.1 : 37735 is now connected to us.
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client
    Sending output to client

    Warning: socket_close() expects parameter 1 to be resource, null given in C:xampphtdocsJAVASCRIPT_PHP_TESTSsocket.example.php on line 110
    Sending output to client

    Warning: socket_write() expects parameter 1 to be resource, null given in C:xampphtdocsJAVASCRIPT_PHP_TESTSsocket.example.php on line 120

    Warning: socket_close() expects parameter 1 to be resource, null given in C:xampphtdocsJAVASCRIPT_PHP_TESTSsocket.example.php on line 110
    Sending output to client

    Warning: socket_write() expects parameter 1 to be resource, null given in C:xampphtdocsJAVASCRIPT_PHP_TESTSsocket.example.php on line 120

    • Selina

      hi,

      i am getting an error.

      Warning: socket_recv() [function.socket-recv]: unable to read from socket [0]: The operation completed successfully.
      in C:xampphtdocssocketclient_receive_msg.php on line 38

      Could not receive data: [0] The operation completed successfully.

      Please Help.
      Thanks in advance.

  • farzaneh

    thx!

  • Cristian

    Your explanation it’s clear as water, thank you so much, you have showed me the path to the solution I need.
    again, thank you very, very much.

  • http://www.facebook.com/chetan.chauhan.9212 Nahuahc Natehc

    Thanks for the fantastic socket tutorial on windows terminal….Just one thing i didn’t understand…when I tried to run it on browser….Nothing is happened…So how could I use it for the chat server??

    • http://www.binarytides.com/ Silver Moon

      if you run the server in a browser, the page shall keep loading since it is a never ending script.
      then you can connect to it from console using the telnet command.

      • http://www.facebook.com/chetan.chauhan.9212 Nahuahc Natehc

        Thanks for reply!!
        Actually I want this script to use for developing a chat application that will run on the browser, and will be used just like done in facebook chating…How can I do it??
        I used a big class PHPWebSocket.php found from googling but, it is too long and tough to understand…

        • http://www.binarytides.com/ Silver Moon

          This post shows the usage of tcp/ip sockets. these are different from websockets.
          tcp/ip sockets are not related to browsers.

          to develop a chat like application use ajax. check out some tutorials on the subject.

      • Selina

        hi,

        i am getting an error.

        Warning: socket_recv() [function.socket-recv]: unable to read from socket [0]: The operation completed successfully.
        in C:xampphtdocssocketclient_receive_msg.php on line 38

        Could not receive data: [0] The operation completed successfully.

        Please Help.
        Thanks in advance.

        Solved it …The IP mentioned is different from the current Google IP.

  • Fab

    Thanks for your extensive tutorial Silver Moon. Most of it works for me but I have the problem that when I press a key in my client console it straight goes to the server. So I can only send single characters. According to your tutorial this is not expected behavior?

    BTW, I do get an error when disconnecting, but I found it is due to unsetting a client resource in the clients array. Using array_splice solved this issue.

    • http://www.binarytides.com/ Silver Moon

      what socket client are you using ? telnet ?
      with telnet the message should not go to server unless the enter key is pressed.

      • Fab

        Maybe it has to do with the Windows environment? But I tried bot windows console telnet and telnet in Putty. They give the same problem.

        • http://www.binarytides.com/ Silver Moon

          yes, on windows the telnet command is in character mode and due to that every key stroke is transmitted right away to the server.

          this can be fixed by either of the following 2 steps :

          1. setting the telnet into line mode
          2. modifying the server code to reply only when it receives a newline.
          3. put putty in passive negotiation mode and it will send only on pressing enter key.

          or use netcat, ncat (from nmap package). it too has same syntax as telnet.

          C:> ncat localhost 5000

          • Fab

            Line mode didn’t do what I expected, but passive mode in putty did the trick. Tnx!

          • Hilal Al-Rajhi

            how can I change telnet input mode into line mode?

          • Hilal Al-Rajhi

            How to change putty to passive mode? All working except this!

          • Hilal Al-Rajhi

            how to set telnet into line mode?

  • jeyshree

    Hai,
    There are two questions.

    Question 1:

    I used the gethostbyname function to get the ip address of google and found the ip address of google as 173.194.38.176.Then i typed the code given under the sub heading “sending data” and in that i replaced the line
    if(!socket_connect($sock , ’74.125.235.20′ , 80))with if(!socket_connect($sock , ’173.194.38.176′ , 80)).It outputs “Socket created
    Connection established
    Message send successfully”.But it is not displaying the google web page why?

    Question 2:
    Similarly i typed the code in receive data but used the ip address as 173.194.38.176 instead of 74.125.235.20 the ip address of google.It outputs every thing from socket created to
    X-Frame-Options: SAMEORIGIN.But it doesnot display the HTML code.Instead it displays”302 moved.the document has been moved”.why?

    • http://www.binarytides.com/ Silver Moon

      Question 1 :

      You have to use the code under “Receiving Data”. It will receive the google web page and display it. The “Sending data” code only sends the http requests and quits.

      Question 2 :

      The “302 moved” message is the output google has send. It means that another http request has to be made to fetch the actual page. Its related to http protocol.
      The socket program is working fine.

  • jeyshree

    hai,

    for me the second program shows an error.the error is”Call to undefined function socket_create() in C:wampwwwhaisocket_creation.php on line 2″.what shall i do now?

    • http://www.binarytides.com/ Silver Moon

      you need to enable the socket extension in wamp. Click the wamp icon in the taskbar, go to
      PHP => PHP extensions and click php_sockets. Make sure it has a tick mark to indicate that it is enabled.

      After that restart apache. Now socket functions should work fine.

      • jeyshree

        thanks it worked

  • jeyshree

    hai,

    for me the there is an error in executing the second program.the error is

    “Call to undefined function socket_create() in C:wampwwwhaisocket_creation.php on line 2″.what shall i do now?

  • Faiyyaz

    so far i have found it perfect!! Thanks :) but i am having issues.. the code works perfect for me on localhost but on my remote server it says “Socket created Could not bind socket : [98] Address already in use” how do i proceed :)

    • Daniel

      Change the socket number you’re attempting to bind. 98 is pretty low, and likely used for something. Pick something high and random.

      • Silver Moon

        98 is the error code, not the port number.

  • Aydın

    Thnks, very nice info.

  • http://twitter.com/inkshawn Shawn Richards

    This is the first Googled socket server that I have found that is robust after trying half a dozen others.

    Unlike other fails that I have tried, this one doesn’t quit the entire socket server when one telnet session disconnects with “^]” followed by “close”. It is a fantastic starting point and well explained…

    Don’t waste your time elsewhere. Use this. It rocks!

  • Doug Thwaites

    Awesome, Cheers!

  • jorge

    I have only one question
    I tried to send received messages to all clients at the same time, but I have not achieved :(
    Try something like this from line 118 does not work:
    for ($i = 0; $i < $max_clients; $i++){
    socket_write($client_socks[$i] , $output);
    }
    Is there any solution?

  • jorge

    can be used to create a http server in php :)

  • hardik

    Warning: socket_bind() [function.socket-bind]: unable to bind address [0]: Only one usage of each socket address (protocol/network address/port) is normally permitted. in C:\xampp\htdocs\First programm\index.php on line 16
    Could not bind socket : [10048] Only one usage of each socket address (protocol/network address/port) is normally permitted.
    please help me i am using this in Windows

    • Silver Moon

      change the port number you are binding the socket to.

  • nikhil gupta

    very nice

  • hh

    very nice

  • http://eye-break.tk Ahsan

    So much great that I have even not seen anything like this in any PHP book.

  • http://www.bharath.co.uk Amarjit Bharath

    A serious well done on this article. I used it as a side note whilst researching PHP sockets in detail.

    Cheers!

  • mohammad

    perfect, this tut is what i was looking for. thank you so much <3

  • Sanin

    Very nice tutorial…saved my lot of time thanks buddy

  • sundar1092

    Very neat info …

  • Webpintoo

    Excellent !! I want to know some more idea about socket programming for web service.

  • Timespace7

    Excellent tutorial !!

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