How does php implement a simple domain name forwarding function?

Domain name forwarding is a common website deployment method, usually used to achieve secondary domain name access to the website. For example, we can set the main domain name to www.example.com and its subdomain name to blog.example.com. In this way, when users visit blog.example.com, they can access the blog page we set.

When implementing domain name forwarding, we usually use scripting languages ​​such as PHP. The following is a simple PHP source code example used to implement the domain name forwarding function.

<?php
// 域名转发配置
$domains = [
  &#39;blog.example.com&#39; => 'blog.php',
  'about.example.com' => 'about.php',
  'contact.example.com' => 'contact.php',
];

// 获取当前访问的域名
$current_domain = $_SERVER['HTTP_HOST'];

// 获取对应的目标文件名
if (isset($domains[$current_domain])) {
  $target_file = $domains[$current_domain];
} else {
  // 如果域名不存在，则默认访问首页
  $target_file = 'index.php';
}

// 跳转到目标页面
header("Location: {$target_file}");
exit;
?>

The above code first defines a $domains array to store the domain name and target file name we want to forward. When users visit these domain names, we redirect them to the corresponding target page.

Next, we use $_SERVER['HTTP_HOST'] to obtain the currently accessed domain name. If the domain name exists in the $domains array, the corresponding target file name is obtained; otherwise, the home page is accessed by default.

Finally, use header("Location: {$target_file}") to redirect the user to the target page. Note that the exit() function must be called after the header() function is called to prevent the script from continuing to execute.

Summary

Through the above PHP source code example, we have implemented a simple domain name forwarding function. When users access the domain name we set, they can jump to the corresponding target page, realizing the need for second-level domain name access. In practical applications, we can also make corresponding optimizations and modifications as needed to achieve more flexible and efficient domain name forwarding functions.

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