What is a socket
socket: two programs on the network connection for data exchange via a two-way communication, a connection as a socket.
Thus socket set operation is composed of two end rare, one of a client (client s) to the server.
socket works
Several key function of the socket
The key function socket 1:
socket_create ($ net parameter 1, $ stream parameters 2, $ protocol parameter 3)
Role: create a socket socket is a network data stream.
Returns: a socket, or is false, parameter error warning issued E_WARNING
php online manual where it says more clearly:
socket_create Creates and returns a socket, also known as a communications node. A typical network connection is constituted by two sockets, one running on the client, the other runs on the server side.
Parameter 1 is: network protocol,
What network protocols? It's on the following three options:
AF_INET: IPv4 network protocol. TCP and UDP can use this protocol. Generally use this, you know.
AF_INET6: IPv6 network protocol. TCP and UDP can use this protocol.
AF_UNIX: local protocol. High performance and low cost of IPC (interprocess communication).
Parameter 2: socket stream, the options are:
SOCK_STREAM SOCK_DGRAM SOCK_SEQPACKET SOCK_RAW SOCK_RDM。
Here only the first two are explained:
SOCK_STREAM TCP protocol sockets.
SOCK_DGRAM UDP protocol socket.
For more information, please link here: http: //php.net/manual/zh/function.socket-create.php
Parameter 3: protocol agreement, the options are:
SOL_TCP: TCP protocol.
SOL_UDP: UDP protocol.
As can be seen here, in fact, the second parameter and the third parameter socket_create function is associated.
For example, if the first argument you use IPv4 protocol: AF_INET, then the second argument is the application of TCP socket: SOCK_STREAM,
Then the third parameter must be used SOL_TCP
The key function 2:
socket_connect ($ socket parameters 1, $ ip parameter 2, $ port 3 parameters)
Action: a socket connection, returns true or false
Parameter 1: socket_create function return value
Parameter 2: ip address
Parameter 3: No. Port
3 key functions:
socket_bind ($ socket parameters 1, $ ip parameter 2, $ port 3 parameters)
Action: binding a socket, the return value is true or false
Parameter 1: socket_create function return value
Parameter 2: ip address
Parameter 3: No. Port
The key function 4:
socket_listen ($ socket parameters 1, $ backlog parameter 2)
Action: a listening socket, the return value is true or false
Parameter 1: socket_create function return value
Parameter 2: The maximum number of sockets listening
The key function 5:
socket_accept($socket)
Role: receiving socket resource information, the successful return information resource socket, failed to false
Arguments: socket_create return value
The key function 6:
socket_read ($ socket parameters 1, $ length parameter 2)
Role: reading resource information socket,
Returns: the success of the socket resource information into a string, failed to false
Parameter 1: socket_create or function return value socket_accept
Length of the string read: 2 Parameter
The key function 7:
socket_write ($ socket parameters 1, $ msg parameter 2, $ strlen 3 parameters)
Effect: the data is written in the socket
Return Value: returns the byte length of the string of success, failure is false
Parameter 1: socket_create or function return value socket_accept
Parameter 2: String
3 parameters: the length of the string
The key function 8:
socket_close($socket)
Role: Closes the socket
Returns: Returns true if successful, failed to false
Arguments: socket_create return value or socket_accept
The eight core function is a function of the socket, here are two relatively important function
socket_last_error ($ socket), parameter socket_create return value, is to get a socket of the last error code number, the return value of the socket code
socket_strerror ($ code), the parameters for the function return value socket_last_error, information acquired code string, error value is returned in the socket
Server-side scripting, server_socket.php
? < PHP // Create a stream socket socket server-side, net protocol IPv4, protocol protocol TCP $ socket = socket_create (AF_INET, SOCK_STREAM, SOL_TCP); / * Bind received stream socket host and port, and the client corresponding * / IF (socket_bind ( $ Socket , '127.0.0.1', 8888) == to false ) { echo 'the bind Server Fail:'. socket_strerror (socket_last_error ()); / * 127.0.0.1 here is the local host test, if you have more than one computer, you can write IP address * / } // listening socket stream IF (socket_listen ( $ socket , 4) == false ) { echo 'the listen Server Fail:'.socket_strerror (() socket_last_error); } // allow the server to obtain an unlimited pass over client information do { / * receiving client pass over the information * / $ accept_resource = socket_accept ( $ socket ); / * action is to accept socket_bind socket_accept () bound to the host sent over socket stream * / IF ( $ accept_resource ! == to false ) { / * read resource clients pass over, and into the string * / $ string = socket_read ( $ accept_resource , 1024 ); / * socket_read function is to read socket_accept () resources and convert it to a string * / echo 'the receive Server iS:'. $ string. Value is PHP_EOL ; // value is PHP_EOL for php of predefined constants linefeed IF ( $ String =! To false ) { $ return_client = 'the receive Server IS:'. $ String . Value is PHP_EOL ; / * write information to the socket stream socket_accept also is feedback information to socket_bind () bound host client * / socket_write ( $ accept_resource , $ return_client , strlen ( $ return_client )); / * socket_write role is to write information to the socket socket_create flow, or to socket_accept sleeved stream writing information * / } the else { echo'socket_read IS Fail' ; } / * socket_close socket_create effect is off () or socket_accept () socket established stream * / socket_close ( $ accept_resource ); } } the while ( to true ); socket_close ( $ Socket ); ?>
Tip: Note that the order of execution socket_bind, socket_listen, socket_accept above three functions can not be changed, that is
Must perform socket_bind, then execute socket_listen, and finally execute socket_accept
Client-side script, client_socket.php
? < PHP // Create a stream socket sockets $ socket = socket_create (AF_INET, SOCK_STREAM, SOL_TCP); / * *************** set socket connectivity options, these two steps you may be omitted ************ * / // receiving socket stream maximum timeout 1 second, followed by a unit of microsecond timeout is set to zero to indicate whether it socket_set_option ( $ Socket , SOL_SOCKET , SO_RCVTIMEO, Array ( "sec" =>. 1, "usec" => 0 )); // send a stream socket 6 seconds maximum timeout socket_set_option ( $ Socket , SOL_SOCKET, SO_SNDTIMEO, Array ( "sec" => . 6, "usec" => 0 )); / * *************** socket connection option is provided, the two steps you can omit ********** ** * / //Socket stream connection service side, this step is to make the stream socket client and server to establish contact IF (socket_connect ( $ socket , '127.0.0.1', 8888) == false ) { echo 'Connect Fail massege:'. Socket_strerror (socket_last_error ()); } the else { $ Message = 'the Hello, Socket! This is a test! ' ; // into GBK encoding, processing garbage problem, depending on your coding the case may be, each person is different encoding // $ message = mb_convert_encoding ($ message ,' GBK ',' UTF-8 '); // string information is written to the server IF (socket_write ( $ Socket , $ message , strlen ( $ message )) == to false ) { echo'Write to Fail'. socket_strerror (socket_last_error ()); } the else { echo . 'Client Write Success' value is PHP_EOL ; // read back to the server socket stream information the while ( $ the callback = socket_read ( $ Socket , 1024 ) ) { echo 'return Message Server IS:'. value is PHP_EOL . $ the callback ; } } } socket_close ( $ Socket ); // work is completed, close the socket stream >?
Test results
Postscript added:
socket_set_option ($ socket parameters 1, $ level parameter 2, $ optname parameter 3, $ optval parameter 4)
This function returns a data stream to the socket set options, it is still a very important function.
参数1：socket_create或者socket_accept的函数返回值
参数2：SOL_SOCKET，好像只有这个选项
参数3与参数4是相关联的，
参数3可为：SO_REUSEADDR SO_RCVTIMEO S0_SNDTIMEO
解释一下：
SO_REUSEADDR 是让套接字端口释放后立即就可以被再次使用
参数3假如是这个，则参数4可以为true或者false
SO_RCVTIMEO 是套接字的接收资源的最大超时时间
SO_SNDTIMEO 是套接字的发送资源的最大超时时间
参数3假如是这两个，则参数4是一个这样的数组array('sec'=>1,'usec'=>500000)
数组里面都是设置超时的最大时间，不过，一个是秒为单位，一个是微秒单位，作用都一样