HomePHP Page 2 - Emulating a Basic Web Server with Sockets in PHP
Taking a quick look at the previous TCP server - PHP
Do you think that programming sockets with PHP is really hard work? Not at all. If you’re still not convinced, read this final part of the series “Handling sockets with PHP.” In three parts, this series shows how to work with low-level sockets in PHP. It introduces some of the typical tasks, such as creating sockets, as well as reading and writing socket data.
Before I start coding the Web server, I’d like you to recall how the previous TCP server was developed. Since the Web server I plan to build will use most of the PHP functions that you learned in the previous installments, you shouldn’t have any problems understanding how it will work.
That said, here is the full source code that corresponds to the previous TCP server, including both procedural and object-oriented approaches:
/* /**************************************************************** / procedural script for building a multi-request TCP server /**************************************************************** */
// define TCP port & local host $port=12345; $host='127.0.0.1'; set_time_limit(0); // create low level socket if(!$socket=socket_create(AF_INET,SOCK_STREAM,0)){ trigger_error('Error creating new socket',E_USER_ERROR); } // tie up socket to TCP port if(!socket_bind($socket,$host,$port)){ trigger_error('Error binding socket to TCP port',E_USER_ERROR); } // begin listening connections if(!socket_listen($socket)){ trigger_error('Error listening socket connections',E_USER_ERROR); } // create comunication socket if(!$comSocket=socket_accept($socket)){ trigger_error('Error creating communication socket',E_USER_ERROR); } $message='This is a simple TCP/IP server created with PHP sockets!'."\r\n"; socket_write($comSocket,$message,strlen($message)); // start a loop and continue reading user input do{ // delay loop execution sleep(10); // read socket input $socketInput=socket_read($comSocket,1024); if(trim($socketInput)!=''){ // if user did not entered the 'STOP" command continue reading data if(trim($socketInput)!='STOP'){ // build socket output $socketOutput='The string you entered was '.$socketInput."\r\n"; // write data back to socket server socket_write($comSocket,$socketOutput,strlen ($socketOutput)); echo 'The string you entered is '.$socketOutput; } else{ // if 'STOP' command was entered close communication socket & terminate all the connections socket_close($comSocket); break; } } } while(true); // close global socket socket_close($socket);
/* /**************************************************************** / 'createSocketServer()' function for building a multi-request TCP server /**************************************************************** */ function createSocketServer($host='127.0.0.1',$port=12345){ set_time_limit(0); // create low level socket if(!$socket=socket_create(AF_INET,SOCK_STREAM,0)){ trigger_error('Error creating new socket',E_USER_ERROR); } // tie up socket to TCP port if(!socket_bind($socket,$host,$port)){ trigger_error('Error binding socket to TCP port',E_USER_ERROR); } // begin listening connections if(!socket_listen($socket)){ trigger_error('Error listening socket connections',E_USER_ERROR); } // create communication socket if(!$comSocket=socket_accept($socket)){ trigger_error('Error creating communication socket',E_USER_ERROR); } $message='This is a simple TCP/IP server created with PHP sockets!'."\r\n"; socket_write($comSocket,$message,strlen($message)); // start a loop and continue reading user input do{ // delay loop execution sleep(10); // read socket input $socketInput=socket_read($comSocket,1024); if(trim($socketInput)!=''){ // if user did not entered the 'STOP" command continue reading data if(trim($socketInput)!='STOP'){ // convert to uppercase socket input $socketOutput='The string you entered was '.$socketInput."\r\n"; // write data back to socket server socket_write($comSocket,$socketOutput,strlen ($socketOutput)); echo 'The string you entered is '.$socketOutput; } else{ // if 'STOP' command was entered close communication socket & terminate all the connections socket_close($comSocket); break; } } } while(true); // close global socket socket_close($socket); }
/* /************************************************************** / 'SocketServer()' class for creating a multi-request TCP server /************************************************************** */ class SocketServer{ var $host; var $port; var $delay=10; var $message="This is a simple TCP/IP server created with PHP sockets!\r\n"; function SocketServer($host='127.0.0.1',$port=12345){ if(!is_int($port)||$port<1||$port>65535){ trigger_error('Invalid port number',E_USER_ERROR); } $this->host=$host; $this->port=$port; $this->connect(); } function connect(){ set_time_limit(0); // create low level socket if(!$socket=socket_create(AF_INET,SOCK_STREAM,0)){ trigger_error('Error creating new socket',E_USER_ERROR); } // tie up socket to TCP port if(!socket_bind($socket,$this->host,$this->port)){ trigger_error('Error binding socket to TCP port',E_USER_ERROR); } // begin listening connections if(!socket_listen($socket)){ trigger_error('Error listening socket connections',E_USER_ERROR); } // create communication socket if(!$comSocket=socket_accept($socket)){ trigger_error('Error creating communication socket',E_USER_ERROR); } socket_write($comSocket,$this->message,strlen($this- >message)); // start a loop and continue reading user input do{ // delay loop execution sleep($this->delay); // read socket input $socketInput=socket_read($comSocket,1024); if(trim($socketInput)!=''){ // if user did not entered the 'STOP" command continue reading data if(trim($socketInput)!='STOP'){ $socketOutput='The string you entered was '.$socketInput."\r\n"; // write data back to socket server socket_write($comSocket,$socketOutput,strlen ($socketOutput)); echo 'The string you entered is '.$socketOutput; } else{ // if 'STOP' command was entered close communication socket & terminate all the connections socket_close($comSocket); break; } } } while(true); // close global socket socket_close($socket); } }
Right, as you can see, I listed above the complete source code for implementing a multi-request TCP server, including a raw procedural script, and of course adding the corresponding “createSocketServer()” function and the “CreateSocket” PHP class. Whether you’re using a procedural approach or an object-based method for coding your applications, I’m sure that one of the above listed implementations of the pertinent TCP server will meet your particular needs.
Now that I reminded you of how a multi-request TCP server can be created, join me in the next section, in order to learn how to emulate a basic Web server on your own testing machine. Go ahead and read the next section.
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