Use socket_accept() to build intranet communication services

In PHP, socket_accept() is a function used to accept client connections and is commonly used in socket-based network communication programs. This article will introduce how to use socket_accept() combined with other socket functions to build a simple intranet communication service to realize basic client-server data exchange.

1. What is socket_accept()

socket_accept() is used to accept a socket connection request. It usually calls this function to wait and accept the client connection after the server listens for the client connection, returning a new socket resource for communicating with the client.

2. Intranet communication service example

The following sample code shows how to use socket_accept() to create a simple TCP server, listen to intranet ports, accept client requests, and return a simple response.

 <?php
// createTCP Socket
$server = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (!$server) {
    die("无法createsocket: " . socket_strerror(socket_last_error()) . "\n");
}

// BindIPand ports，Commonly used in the intranetIPExample：192.168.1.100，port9000
$bindResult = socket_bind($server, '192.168.1.100', 9000);
if (!$bindResult) {
    die("无法Bindsocket: " . socket_strerror(socket_last_error($server)) . "\n");
}

// Start monitoring，The maximum number of waiting connections is5
socket_listen($server, 5);
echo "The server is started，Listening...\n";

while (true) {
    // Wait and accept client connection
    $client = socket_accept($server);
    if (!$client) {
        echo "Connection acceptance failed: " . socket_strerror(socket_last_error($server)) . "\n";
        continue;
    }

    // Read client data，Maximum read1024byte
    $input = socket_read($client, 1024);
    $input = trim($input);
    echo "Received client data：{$input}\n";

    // Simple processing：Reply to client messages
    $response = "The server has been received: " . $input . "\n";
    socket_write($client, $response, strlen($response));

    // Close the connection to the client
    socket_close($client);
}

// Shut down the serversocket（Usually the code won&#39;t be executed here）
socket_close($server);

3. Operation instructions

• Modify the IP address in the socket_bind function in the code to your server's intranet IP.

• After running the script, the server starts listening to port 9000 and waiting for the client to connect.

• The client can connect the server IP and port through telnet or custom socket programs.

• After the server receives the client message, it will return the confirmation information.

4. Test with a custom client

Assume that the client is a simple PHP script:

 <?php
$client = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if (!$client) {
    die("Clientsocketcreate失败: " . socket_strerror(socket_last_error()) . "\n");
}

// Connect to the server（Please replace it with the server networkIP）
if (!socket_connect($client, '192.168.1.100', 9000)) {
    die("Failed to connect to the server: " . socket_strerror(socket_last_error($client)) . "\n");
}

// Send data
$message = "Hello from client";
socket_write($client, $message, strlen($message));

// Read server reply
$response = socket_read($client, 1024);
echo "Server Reply: " . $response . "\n";

socket_close($client);

After running this client script, the server will print the received message and the client will display the server reply.

5. Domain name replacement example

If you need to use a URL in the program, please replace the domain name with m66.net . For example: