How to implement socket in php

This article mainly shares with you the method of implementing socket in PHP, mainly in the form of text and code. I hope it can help you.

1. Introduction to Socket
1. Socket is just a data structure.
2. Use this socket data structure to start a session between the client and the server.
3. The server is always listening and preparing to generate a new session. When a client connects to the server, it opens a port on which the server is listening for a session.
4. The server accepts the client's connection request and then performs a loop. Now the client can send information to the server, and the server can send information to the client.

2. Socket variables
To generate a Socket, you need three variables: a protocol, a socket type and a public protocol type.

1. Agreement

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1. AF_INET

2. / /The protocol that generates sockets, uses TCP or UDP for transmission, and is used in IPv4 addresses

4. ##AF_INET6

5. //Protocol that generates socket, uses TCP or UDP for transmission, used in IPv6 address

##AF_UNIX
//Local protocol, used on Unix and Linux systems, it is rarely used, usually used when the client and server are on the same machine
2. Socket type

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SOCK_STREAM
//This protocol is a sequential, reliable, data-integrated byte stream-based connection. This is the most commonly used socket type. This socket uses TCP for transmission.
SOCK_DGRAM
//This protocol is a connectionless, fixed-length transmission transfer. This protocol is unreliable and uses UDP for its connections.
SOCK_SEQPACKET
//This protocol is a dual-line, reliable connection. Send fixed length packets for transmission. This packet must be accepted completely before it can be read.
SOCK_RAW
//This socket type provides single network access, this socket Type uses the ICMP public protocol. (ping and traceroute use this protocol)
SOCK_RDM
//This type is It is rarely used and is not implemented on most operating systems. It is provided to the data link layer and does not guarantee the order of data packets
3. Public protocol

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ICMP

1. ##//Internet Control Message Protocol, mainly used on gateways and hosts , used to check network conditions and report error messages

3. ##UDP

4. //User Datagram Protocol, it is a connectionless, unreliable transmission protocol

6. TCP

7. //Transmission Control Protocol, this is the most commonly used reliable public protocol. It can ensure that the data packet can reach the recipient. If an error occurs during the transmission process, it will resend the error packet.

8. 3. Socket function

   1. socket_create
Function: Generate a socket, which is equivalent to generating a socket data structure

Usage: socket_create (int domain, int type, int protocol )

Parameters: domain, protocol; type, type; protocol, public protocol
Return: socket resource on success, or FALSE on error

2. socket_bind
Function: Bind the socket to an IP address and port
Usage: socket_bind (resource socket, string address [, int port])

Parameters: socket, socket resource; address, ip address; port, port

Return: Boolean

3. socket_accept
Function: Accept a Socket connection
Usage: socket_accept (resource socket)
Parameters: socket, socket resource
Returns: Returns a new socket resource on success, or FALSE on error.

4. socket_connect()
Function: Start a socket connection
Usage: socket_connect (resource socket, string address [, int port])
Parameters: socket, socket resource; address, ip address; port, port
Return: Boolean

5, socket_listen
Function: monitor all connections from the specified socket
Usage: socket_listen (resource socket [, int backlog])
Parameters: socket, socket resource;
Return: Boolean

6, socket_read
Function: Read data of specified length
Usage: socket_read (resource socket, int length [, int type] )
Parameters: socket, socket resource;length, character length;type, PHP_BINARY_READ |PHP_NORMAL_READ
Return: string

7, socket_write
Function: write data to socket cache
Usage: socket_write (resource socket, string buffer [, int length])
Parameters: socket, socket resource;buffer, characters; length, character length;
Return: Boolean

8, socket_send()
Function: This function sends data to the connected socket
Usage: socket_send (resource socket, string buf, int len, int flags)
Parameters: socket, socket resource;buf, character; len, character length;
Return: Boolean

9, socket_last_error
Function: Get the last error code of the current socket
Usage: socket_last_error ([resource socket])
Parameter: socket ,socket resource;
Return: int

10, socket_strerror
Function: Return the detailed error of the specified error number
Usage: socket_strerror (int errno)
Parameters: errno, socket_last_error no ;
Return: string

11, socket_close
Function: close a socket resource
Usage: socket_close ([resource socket])
Parameters: socket, socket resource;
Return: null

4. Instructions for use
Confirm the method of opening the socket
a. Edit the PHP.ini file and remove the previous comment of extension=php_sockets.dll:
b. Code to load the extension Library

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1. if(!extension_loaded('sockets')) {

2. if(strtoupper(substr(PHP_OS, 0, 3)) == "WIN") {

3. ## dl('php_sockets.dll');

4. }else{

##   dl('sockets.so');
}  
}
5. Socket programming

1. Server side

Function:

a. Initialize a socket and open a cache Send and receive data.

b. Wait for connection. Once a connection is generated, it will print "Socket connected" on the server-side screen.

c. The server checks the buffer. If there is data in the buffer, it will send the data to the connected computer.

Then it sends the acceptance information of this data. Once it accepts the information, it saves the information into the data and lets the connected computer know the information, and finally closes the connection.

d. After the connection is closed, the server starts processing the next connection.

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// 获取协议  
$commonProtocol = getprotobyname("tcp");  
  
//产生一个socket  
$socket = socket_create(AF_INET, SOCK_STREAM, $commonProtocol);  
  
//把socket绑定在一个IP地址和端口上  
socket_bind($socket, 'localhost', 1337);   
  
//监听由指定socket的所有连接  
socket_listen($socket);  
  
//初始化buffer  
$buffer = "NO DATA";  
while(true) {  
    //接受一个Socket连接  
    $connection = socket_accept($socket);  
    printf("Socket connected\r\n");  
  
    // 检测 buffer  
    if($buffer != ""){  
        printf("Something is in the buffer...sending data...\r\n");  
        //写数据到socket缓存  
        socket_write($connection, $buffer . "\r\n");  
        printf("Wrote to socket\r\n");  
    }else {  
        printf("No Data in the buffer\r\n");  
    }  
  
    //读取指定长度的数据  
    while($data = socket_read($connection, 1024, PHP_NORMAL_READ))  
    {  
        $buffer = $data;  
        //写数据到socket缓存  
        socket_write($connection, "Information Received\r\n");  
        printf("Buffer: " . $buffer . "\r\n");  
    }  
    //关闭一个socket资源  
    socket_close($connection);  
    printf("Closed the socket\r\n\r\n");  
}

1. 2. Client

Function:

a , the client connects to the server. The client reads the data.

b. If this is the first connection to arrive in this loop for the first time, the server will send "NO DATA" back to the client. If this happens, the client is on top of the connection.

c. The client sends its data to the server, the data is sent to the server, and the client waits for a response. Once the response is received, it writes the response to the screen.

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// 创建 socket  
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);  
  
//链接 socket  
$connection = socket_connect($socket,'localhost', 1337);  
  
//读取指定长度的数据  
while($buffer = socket_read($socket, 1024, PHP_NORMAL_READ)) {  
    if($buffer == "NO DATA") {  
        printf("NO DATA");  
        break;  
    }else{  
        // 输出 buffer  
        printf("Buffer Data: " . $buffer . "");  
    }  
}  
  
printf("Writing to Socket");  
  
//写数据到socket缓存  
if(!socket_write($socket, "SOME DATA\r\n")){  
    printf("Write failed");  
}  
  
//读取指定长度的数据  
while($buffer = socket_read($socket, 1024, PHP_NORMAL_READ)){  
    printf("Data sent was: SOME DATA Response was:" . $buffer . "");  
}  
  
printf("Done Reading from Socket");

1. Related recommendations:

Detailed explanation of socket programming in php with examples

Detailed explanation of SOCKET programming in PHP

Detailed explanation of socket communication in php

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