About the network protocols involved in socketTCP, UDPah, whatsocket three-way handshake, etc. There are very detailed explanations of these network protocols on the Internet, so I won’t go into them here, just a screenshotsocket Let you take a look at the process diagram of establishing a socket:
# I worked hard to steal this picture from others. You must take a good look at it. At the same time, I would also like to express my gratitude to the author whose screenshot was stolen from me. I would like to express my gratitude to myself for stealing your picture. The pattern expresses my apologies, and I hope you don’t care about it. I am too lazy to draw pictures (actually it means I am not confident in my drawing skills, haha).
How does socket establish a connection? As mentioned above, the process of establishing a connection is essentially the same as the connection between the client and server of
mysql. The difference from mysql is that the server and client of mysql have been edited for us, we only need to apply That's it. However, the critical moment has come. socket It provides us with nothing. The only thing it provides us is: dozens of socketfunction. The implication is that socketProgramming requires us to create the server and client ourselves, that is to say, ``socketProgramming``—— means we need to build a server and client application similar to mysql. Having said that, I would like to ask, do you think this socket is a headache? It neither creates a server nor a client for us to apply. We have to use the functions of socket to create a network protocol suite of our own. Does it give you a headache to connect to the application? There's nothing you can do about the headache. If you need your own application, you still have to deal with socket. Haha, this is just a digression, I won’t say much, let’s get to the point. Before you are confused by socket programming, I still let you take a look at socket Several key functions, let me first explain to you their respective functions. Otherwise, if someone who has no foundation in socket reads this, I'm afraid that after reading it, you will decisively skip this article and learn about from now on. sockethas a phobia. Haha, say more. The key functions of socket1： socket_create($netparameter1，$streamparameter2,$protocolparameter3) Function: Create a socket socketword, to put it bluntly, it is a network data stream. ## Return value: a socket, or false, parameter error E_WARNINGWarning ## The online manual of php makes it clearer: socket_createCreate and return a socket, also called a communication node. A typical network connection consists of 2 sockets, one running on the client side and the other running on the server side. php online manual. Do you see that the meaning here is exactly the same as the client and server that I mentioned repeatedly above? hehe. 1 is: network protocol, What are the network protocols? It has the following three options: AF_INET： IPv4 Network protocol. TCP and UDP can both use this protocol. This is generally used, you know. AF_INET6： IPv6 network protocol. TCP and UDP can both use this protocol. AF_UNIX: Local communication protocol. IPC (Inter-Process Communication) with high performance and low cost. Parameter 2: Socket stream, options are: SOCK_STREAM SOCK_DGRAM SOCK_SEQPACKET SOCK_RAW SOCK_RDM. # SOCK_STREAM TCP Protocol socket. SOCK_DGRAM UDP protocol socket. For more information, please link here: http://php.net/manual/zh/function.socket-create.php ## Parameter 3: protocol protocol, the options are: SOL_TCP： TCP protocol. SOL_UDP： UDPProtocol. It can be seen from here that in fact, the second parameter and the third parameter of the socket_create function are related. For example, if your first parameter uses the IPv4 protocol: AF_INET, then the second parameter uses TCP Socket: SOCK_STREAM, ## Then The third parameter must be SOL_TCP, should not be difficult to understand. TCP protocol socket, of course only the TCP protocol can be used ,Yes or no? If you use UDP socket, then I won’t say how to choose the third parameter, haha, you know.
## Key function 2： socket_connect($socketparameter1,$ipparameter2, $portparameter3) Function: Connect a socket, the return value is true or false Parameters 1: Function return value of socket_create Parameters 2：ipAddress ## Parameter 3：Port number
Key function 3： socket_bind($socketparameter1,$ipparameter2,$portparameter3) Function: Bind a socket, the return value is true or false Parameter1: The function return value of socket_create Parameters2：ipAddress Parameter 3: Port number Key function 4 ： socket_listen($socketparameter1,$backlog parameter2) Function: Listen to a socket, the return value is true or false Parameters1: Function return value of socket_create Parameter 2: Maximum number of listening sockets Key function5： socket_accept($socket) ## kind may may may may Function: Receive the resource information of the socket, and return the information resource of the socket if successful, and if it fails. false Parameter: function return value of socket_create Key function6：## socket_read($socket parameter 1, $length parameter 2) Function: Read the resource information of the socket, ## Return value: Successfully convert the socket resource into string information, Failure is Parameter 1: The function return value of or socket_accept Parameter 2: The length of the read string
Key function ： socket_write($socketparameter1，$msgparameter2 ,$strlenParameter3) Function: Write data into the socket Return value: Successfully returns the byte length of the string, failure is false Parameter 1: The function return value of socket_create or socket_accept parameters 2: String Parameter 3: The length of the string Key function 8： ## socket_close($socket ) Function: Close the socket Return value: true is returned on success, false ## on failure Parameters : The function return value of socket_create or socket_accept These eight functions are the core functions of socket. Here are two more important functions socket_last_error($socket), parameters It is the return value of socket_create. Its function is to obtain the last error code number of the socket. The return value socketcode socket_strerror($code), the parameter is the return value of the socket_last_error function, get codeThe string information, the return value is the socket error message These two functions are still very important in socket programming Importantly, when writing socket programming, I think you still have to use it, especially for novices, it can be used for debugging The following is the code, pay attention, please read my comments carefully, comments are very important, comments are very important, comments are very important, important things should be shouted three times, haha. Server script, D:\vhost\test\socket\server_socket.php Client script, D:\vhost\test\socket \client_socket.php How to test these two scripts? First open the dos window of windows, which is the cmd black window, and then run php D:\vhost\test\socket\server_socket.php, Let the server-side black window continue to run, Secondly, the php client script can be run through the browser, or you can open another cmd black window to run php D:\vhost\test\socket\client_socket.php Please note here: the running name of php must be added to the Windows environment variable , if you don’t know how to add it, Please enter the php running command directory and run it with an absolute command, or you can add the php command to the environment variable in Baidu This is my situation, your file address may be different from mine, please operate according to your address, otherwise, you will be responsible for the consequences, haha above As mentioned before, socket programming requires a server to communicate, so the black window on the server must be kept open. ## Postscript added: socket_set_option($socketParameters1 ，$level Parameters2，$optname Parameters3,$optval Parameters4) The function of this function is to set data flow options for the socket, and it is also a very important function. Parameter 1: socket_create or socket_accept## The function return value of # Parameters 2: SOL_SOCKET, it seems that this is the only option Parameter 3 is related to parameter 4, Parameters3can be:SO_REUSEADDR SO_RCVTIMEO S0_SNDTIMEO Explanation Here's a look: SO_REUSEADDR It allows the socket port to be used again immediately after it is released Parameter 3If this is the case, the parameter 4 can be true or false SO_RCVTIMEO is the maximum timeout of the socket’s receiving resource ##SO_SNDTIMEO is the socket’s sending resource The maximum timeout time Parameter3If it is these two, then parameter4is an array like thisarray('sec'=>1,'usec'=>500000) The maximum timeout time is set in the array, but one is in seconds and the other is in microseconds, and the effect is the same Related recommendations:<?php//创建服务端的socket套接流,net协议为IPv4，protocol协议为TCP$socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP); /*绑定接收的套接流主机和端口,与客户端相对应*/
if(socket_bind($socket,'127.0.0.1',8888) == false){ echo 'server bind fail:'.socket_strerror(socket_last_error()); /*这里的127.0.0.1是在本地主机测试，你如果有多台电脑，可以写IP地址*/
} //监听套接流
if(socket_listen($socket,4)==false){ echo 'server listen fail:'.socket_strerror(socket_last_error());
}//让服务器无限获取客户端传过来的信息do{ /*接收客户端传过来的信息*/
$accept_resource = socket_accept($socket); /*socket_accept的作用就是接受socket_bind()所绑定的主机发过来的套接流*/
if($accept_resource !== false){ /*读取客户端传过来的资源，并转化为字符串*/
$string = socket_read($accept_resource,1024); /*socket_read的作用就是读出socket_accept()的资源并把它转化为字符串*/
echo 'server receive is :'.$string.PHP_EOL;//PHP_EOL为php的换行预定义常量
if($string != false){ $return_client = 'server receive is : '.$string.PHP_EOL; /*向socket_accept的套接流写入信息，也就是回馈信息给socket_bind()所绑定的主机客户端*/
socket_write($accept_resource,$return_client,strlen($return_client)); /*socket_write的作用是向socket_create的套接流写入信息，或者向socket_accept的套接流写入信息*/
}else{ echo 'socket_read is fail';
} /*socket_close的作用是关闭socket_create()或者socket_accept()所建立的套接流*/
socket_close($accept_resource);
}
}while(true);
socket_close($socket);<?php //创建一个socket套接流
$socket = socket_create(AF_INET,SOCK_STREAM,SOL_TCP); /****************设置socket连接选项，这两个步骤你可以省略*************/
//接收套接流的最大超时时间1秒，后面是微秒单位超时时间，设置为零，表示不管它
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, array("sec" => 1, "usec" => 0)); //发送套接流的最大超时时间为6秒
socket_set_option($socket, SOL_SOCKET, SO_SNDTIMEO, array("sec" => 6, "usec" => 0)); /****************设置socket连接选项，这两个步骤你可以省略*************/
//连接服务端的套接流，这一步就是使客户端与服务器端的套接流建立联系
if(socket_connect($socket,'127.0.0.1',8888) == false){ echo 'connect fail massege:'.socket_strerror(socket_last_error());
}else{ $message = 'l love you 我爱你 socket'; //转为GBK编码，处理乱码问题，这要看你的编码情况而定，每个人的编码都不同
$message = mb_convert_encoding($message,'GBK','UTF-8'); //向服务端写入字符串信息
if(socket_write($socket,$message,strlen($message)) == false){ echo 'fail to write'.socket_strerror(socket_last_error());
}else{ echo 'client write success'.PHP_EOL; //读取服务端返回来的套接流信息
while($callback = socket_read($socket,1024)){ echo 'server return message is:'.PHP_EOL.$callback;
}
}
}
socket_close($socket);//工作完毕，关闭套接流
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