Study the underlying development principles of PHP: Detailed explanation of file processing and IO operation optimization techniques

Study on the underlying development principles of PHP: Detailed explanation of file processing and IO operation optimization techniques

Introduction:
PHP is a widely used server-side scripting language. The underlying development principles are critical to optimizing performance and improving user experience. This article will deeply study the file processing and IO operation optimization techniques in the underlying development principles of PHP, and explain it in detail with code examples.

1. File processing optimization skills
In PHP development, it is often necessary to read, write, modify and delete files. In order to improve the efficiency of file processing, we can adopt the following optimization techniques:

1. Use multiple processes or multi-threads to process file IO operations
   Single-threaded IO operations will cause performance bottlenecks. By using multiple processes Or multi-threading can realize parallel processing of multiple IO operations. The following is a sample code that uses multiple processes to handle file IO operations:

<?php
$files = ['file1.txt', 'file2.txt', 'file3.txt'];
$result = [];

for ($i = 0; $i < count($files); $i++) {
    $pid = pcntl_fork(); // 创建子进程

    if ($pid == -1) {
        die('Fork failed');
    } elseif ($pid == 0) {
        // 子进程处理文件IO操作
        $file = $files[$i];
        // ...
        exit(); // 子进程退出
    } else {
        // 父进程记录子进程ID
        $result[$i] = $pid;
    }
}

// 等待子进程退出
foreach ($result as $pid) {
    pcntl_waitpid($pid, $status);
}
?>

2. Reduce the number of file reads and writes as much as possible
   Reducing the number of file reads and writes can reduce the overhead of IO operations. When reading a file, we can use the memory functions (file_get_contents, file_put_contents) provided by PHP to read or write the file at once. The following is a sample code that uses file_get_contents and file_put_contents to read and write files:

<?php
// 一次性读取文件
$data = file_get_contents('file.txt');

// 一次性写入文件
file_put_contents('file.txt', $data);
?>

3. Use efficient file opening methods
   When opening a file, you can use flags related to file operations bit to specify the opening method. For example, use the "r" flag to open a file for reading only, and use the "w" flag to open a file for writing only. Reasonable selection of file opening methods can reduce the overhead of IO operations. The following is a sample code that uses flag bits to open a file:

<?php
// 以只读方式打开文件
$handle = fopen('file.txt', 'r');
// ...
fclose($handle);
?>

2. IO operation optimization skills
In addition to file processing, network IO operations are also an important part of PHP underlying development. In order to improve the performance of network IO operations, we can use the following optimization techniques:

1. Use non-blocking IO operations
   By default, PHP's network IO operations are blocking, that is, every IO The operation must wait for the result to be returned before continuing with the next instruction. In order to improve the concurrency and throughput of IO operations, non-blocking IO operations can be used. The following is a sample code using non-blocking IO operations:

<?php
// 创建非阻塞socket
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_nonblock($socket);

// 连接服务器
socket_connect($socket, '127.0.0.1', 8080);

// 等待连接完成
$read = [$socket];
$write = [$socket];
$except = [];
socket_select($read, $write, $except, 5);

// 发送数据
$buffer = 'Hello, World!
';
socket_write($socket, $buffer, strlen($buffer));

// 接收数据
$result = '';
socket_recv($socket, $result, 1024, 0);

// 关闭连接
socket_close($socket);
?>

2. Set the IO operation timeout reasonably
   Due to the uncertainty of the network environment, IO operations sometimes fail due to network abnormalities or The server is unresponsive and causes blocking. In order to avoid long-term blocking, you can set the timeout for IO operations. The following is a sample code that uses socket_set_option to set the IO operation timeout:

<?php
// 创建socket
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

// 设置连接超时时间为2秒
socket_set_option($socket, SOL_SOCKET, SO_RCVTIMEO, ['sec'=>2, 'usec'=>0]);

// 连接服务器
socket_connect($socket, '127.0.0.1', 8080);

// 发送数据
$buffer = 'Hello, World!
';
socket_write($socket, $buffer, strlen($buffer));

// 关闭连接
socket_close($socket);
?>

Conclusion:
This article mainly studies the file processing and IO operation optimization techniques in the underlying development principles of PHP, combined with the code Examples are explained in detail. In terms of file processing, it is recommended to use multiple processes or multi-threads to handle file IO operations, reduce the number of file reads and writes, and use appropriate file opening methods. In terms of IO operations, it is recommended to use non-blocking IO operations and set the IO operation timeout reasonably. These optimization techniques can significantly improve the performance and user experience of PHP, and are very helpful for underlying optimization in actual development.

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