PHP website performance optimization: How to reduce HTTP requests to improve access speed?

PHP website performance optimization: How to reduce HTTP requests to improve access speed?

Summary: When developing a PHP website or web application, understanding how to reduce HTTP requests is critical to improving the speed and performance of the website. This article will introduce some optimization techniques and methods, such as merging and caching files, using sprites and data URIs, reducing redirect requests, etc., to reduce the number of HTTP requests and improve website performance.

Keywords: PHP, performance optimization, HTTP request, access speed, merged files, cached files, sprites, data URI, redirect requests

1. Merged and cached files

1. Merge CSS and JavaScript files

Merge all CSS files and JavaScript files into one file, which can reduce the number of HTTP requests. By reducing the number of files, you can increase the loading speed of your website. Here is an example of merging CSS files:

<?php
$css_files = ['style1.css', 'style2.css', 'style3.css'];

$combined_css = '';
foreach ($css_files as $file) {
    $combined_css .= file_get_contents($file);
}

file_put_contents('combined.css', $combined_css);
?>

2. Caching files

Using caching can avoid duplicate HTTP requests. If the file content does not change frequently, you can cache the file locally and use the cached file directly when needed. The following is an example of a cached file:

<?php
$cached_file = 'cached.html';
$expiration_time = 3600; // 缓存时间为1小时

if (file_exists($cached_file) && time() - filemtime($cached_file) < $expiration_time) {
    // 使用缓存文件
    readfile($cached_file);
} else {
    // 生成新的HTML内容
    ob_start();
    // ... 生成HTML内容的代码 ...
    $html_content = ob_get_clean();
    
    // 写入缓存文件
    file_put_contents($cached_file, $html_content);
    
    // 输出HTML内容
    echo $html_content;
}
?>

2. Use sprites and data URI

1. Sprites

Combine multiple small images into A sprite that can reduce the number of HTTP requests. By using the sprite's position and size properties in CSS, you can load only one large image and then display different smaller images by adjusting the position. The following is an example of using a sprite map:

.icon {
    background: url(sprite.png) no-repeat;
    width: 30px;
    height: 30px;
}

.icon-home {
    background-position: 0 0;
}

.icon-play {
    background-position: -30px 0;
}

.icon-setting {
    background-position: -60px 0;
}

2. Data URI

Convert the image into the form of a data URI, which can reduce the number of HTTP requests. Data URIs encode images into Base64 strings and embed them directly into CSS or HTML files. The following is an example of using data URI:

.icon {
    background: url(data:image/png;base64,iVBORw0KG...) no-repeat;
    width: 30px;
    height: 30px;
}

3. Reduce redirect requests

Redirect requests will increase the number of additional HTTP requests, thereby reducing the performance of the website. Therefore, minimizing redirect requests is one of the important strategies to improve website performance. The following is an example of reducing redirect requests:

<?php
$redirect_url = '';

if (condition1) {
    $redirect_url = 'redirect1.php';
} elseif (condition2) {
    $redirect_url = 'redirect2.php';
}

if ($redirect_url) {
    header('Location: ' . $redirect_url);
    exit;
}
?>

Summary: By merging and caching files, using sprites and data URIs, reducing redirect requests and other techniques, you can effectively reduce the number of HTTP requests, thereby improving the performance of your PHP website. Access speed and performance. Developers should choose appropriate optimization methods based on specific circumstances and combine them with other performance optimization techniques to improve the user experience of the website.

Reference:

• https://www.smashingmagazine.com/2009/04/speed-up-your-website-with-better-dns-usage/
• https://gtmetrix.com/why-use-gtmetrix.html
• https://developer.mozilla.org/en-US/docs/Learn/Performance
• https://www.sitepoint.com/web-performance-for-beginners/

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