Use socket_wsaprotocol_info_import with socket_listen to implement server programs

1. Function introduction

• This is a function in PHP's socket extension that is specifically designed for the Windows platform. It is used to import a WSAPROTOCOL_INFO structure so that processes can share or pass sockets. This feature is particularly important for server-side programs in multi-process models, allowing different processes to share the same socket.

• socket_listen

  This is a cross-platform listening socket function, which is used to make a socket enter the listening state and wait for the client's connection request. It is an indispensable step for server-side programs.

2. Application scenario description

Suppose you want to improve the concurrent processing capabilities of the server through a multi-process model. You can first create a listening socket in the main process, and then use socket_wsaprotocol_info_export (with socket_wsaprotocol_info_import ) to pass this listening socket to the child process. The child process then calls socket_listen to enter the listening state and waits for the client to connect.

3. Code example

Here is a simplified example that demonstrates how to use socket_wsaprotocol_info_import and socket_listen to build a simple server listener.

 <?php
// Create a TCP Sockets
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
    die("socket_create() failed: " . socket_strerror(socket_last_error()) . "\n");
}

// Bind to local address and port
if (!socket_bind($socket, '0.0.0.0', 12345)) {
    die("socket_bind() failed: " . socket_strerror(socket_last_error($socket)) . "\n");
}

// 将Sockets置于监听状态
if (!socket_listen($socket, 5)) {
    die("socket_listen() failed: " . socket_strerror(socket_last_error($socket)) . "\n");
}

// Export WSAPROTOCOL_INFO
$wsaproto_info = socket_wsaprotocol_info_export($socket);
if ($wsaproto_info === false) {
    die("socket_wsaprotocol_info_export() failed\n");
}

// Assume here will $wsaproto_info Pass to another process（Demo import directly）
$imported_socket = socket_wsaprotocol_info_import($wsaproto_info);
if ($imported_socket === false) {
    die("socket_wsaprotocol_info_import() failed\n");
}

// 通过导入的Sockets继续监听
if (!socket_listen($imported_socket, 5)) {
    die("socket_listen() on imported socket failed\n");
}

echo "Server listening start，Waiting for client connection...\n";

// Simple acceptance of a connection example
$client_socket = socket_accept($imported_socket);
if ($client_socket === false) {
    die("socket_accept() failed\n");
}

echo "Client is connected\n";

// 关闭Sockets
socket_close($client_socket);
socket_close($imported_socket);
socket_close($socket);
?>

4. Key points analysis

• Multi-process shared sockets <br> Through socket_wsaprotocol_info_export and socket_wsaprotocol_info_import , the main process and child process can share the same listening socket to avoid repeated binding of ports causing conflicts.

• Improve performance and stability <br> Multiple processes listening to the same port can share the pressure of client connection requests and improve overall throughput.

• Error handling and resource management <br> In production environments, it is recommended to improve exception handling to ensure that each socket is correctly closed when not needed to avoid resource leakage.

5. Summary

The combination of socket_wsaprotocol_info_import and socket_listen provides PHP server programs with low-level efficient network communication support, especially suitable for multi-process concurrency scenarios. Understanding and using these two functions reasonably can significantly improve the performance and stability of server programs.