Home arrow PHP arrow Page 3 - Developing an Extensible TCP Server with Sockets in PHP

Expanding the original TCP server: processing multiple client requests - PHP

Are you interested in learning how to manipulate low-level sockets in PHP? Your search has finished. This is the second part of the series “Handling sockets in PHP,” and hopefully you’ll find in it valuable material regarding the creation and manipulation of sockets with PHP, in conjunction with numerous illustrative hands-on examples that will help you build socket servers in a few easy steps.

  1. Developing an Extensible TCP Server with Sockets in PHP
  2. A quick look at the previous TCP server
  3. Expanding the original TCP server: processing multiple client requests
  4. Defining the createSocketServer() function and the SocketServer class
By: Alejandro Gervasio
Rating: starstarstarstarstar / 16
May 30, 2006

print this article



Once you've learned how to create a low-level socket in PHP, in conjunction with reading and writing socket data, expanding the previous TCP server is a fairly standard process. Basically I'm not going to introduce new terms or concepts to achieve the new desired functionality.

In short, what I'll do next is change the original procedural script and introduce a simple loop structure, in order to provide the server with the ability to keep running over and over again, attending to multiple client requests, until it is deliberately stopped.

Here is the source code for the improved TCP server, now capable of processing many requests:

// define  TCP port & local host
// create low level socket
    trigger_error('Error creating new socket',E_USER_ERROR);
// tie up socket to TCP port
    trigger_error('Error binding socket to TCP
// begin listening connections
    trigger_error('Error listening socket
// create communication socket
    trigger_error('Error creating communication
$message='This is a simple TCP/IP server created with PHP
// start a loop and continue reading user input
    // delay loop execution
    // read socket input
        // if user did not entered the 'STOP" command continue
reading data
            // build socket output 
            $socketOutput='The string you entered was
            // write data back to socket server
            echo 'The string you entered is '.$socketOutput;
            // if 'STOP' command was entered close communication
socket & terminate all the connections
// close global socket

Even though the script shown above is closely similar to the one I wrote in the first part of this series, it also exposes some differences worth mentioning. First, please notice the inclusion of the "do-while" loop, in order to keep the server listening over and over for incoming client connections.

Second, the server will display a simple welcome message, and will only stop listening for requests when the client sends out the "STOP" command. If this happens, the loop is halted and both the general and communication sockets are properly closed.

Additionally, in this example, I slightly modified the behavior of the server, so each time the client transmits a string, it will be redisplayed to the client. Of course, there's plenty of room to experiment here, and certainly you may want to change the source code in order to make the server perform a more useful task.

Now, take a look at the following screen shots, which depict the whole client-server interaction process using a Microsoft Telnet client:

As you can see on the above images, after starting the server from the PHP command line, I used a simple Telnet client (like Microsoft's) and made some requests to it, by entering different strings. In all cases, the server displayed the inputted string in the console, and only stopped working when I entered the "STOP" command.

In this example, hopefully you could see how data comes in and out through the communication channel established between the server and the client. Simple and educational, isn't it?

At this point, I hope you've already grasped the driving logic for creating a TCP server, which now processes multiple requests from a specific client, by using some socket programming PHP functions.

Therefore, come with me and read the last section of the article, in order to learn how to translate the procedural script you saw before into a compact and reusable function, and an additional PHP class.

>>> More PHP Articles          >>> More By Alejandro Gervasio

blog comments powered by Disqus
escort Bursa Bursa escort Antalya eskort


- Hackers Compromise PHP Sites to Launch Attac...
- Red Hat, Zend Form OpenShift PaaS Alliance
- PHP IDE News
- BCD, Zend Extend PHP Partnership
- PHP FAQ Highlight
- PHP Creator Didn't Set Out to Create a Langu...
- PHP Trends Revealed in Zend Study
- PHP: Best Methods for Running Scheduled Jobs
- PHP Array Functions: array_change_key_case
- PHP array_combine Function
- PHP array_chunk Function
- PHP Closures as View Helpers: Lazy-Loading F...
- Using PHP Closures as View Helpers
- PHP File and Operating System Program Execut...
- PHP: Effects of Wrapping Code in Class Const...

Developer Shed Affiliates


Dev Shed Tutorial Topics: