How does PHP handle URL parameters and routing?

In web development, URL query parameters and route resolution are a very important part. Whether you are building a simple static web page or a complex web application, understanding how to handle URL query parameters and route resolution is necessary. This article will introduce how PHP handles URL query parameters and route resolution.

1. Processing of URL query parameters

URL query parameters refer to the part after the question mark contained in the URL, which is used to pass parameters to the server. In PHP, you can use the $_GET superglobal variable to get the value of a URL query parameter. The following is a simple example:

// 当URL为 http://example.com/page.php?id=1&name=John 时
$id = $_GET['id']; // 获取id参数的值，结果为1
$name = $_GET['name']; // 获取name参数的值，结果为John

When processing URL query parameters, you need to pay attention to the following points:

1. Use the isset() function to determine whether the parameters exist to avoid Error defining variable. You can use the following code to judge:

if(isset($_GET['id'])){
    $id = $_GET['id'];
}

2. For parameters that need to pass multiple values, you can use an array to process. For example, the URL is http://example.com/page.php?category[]=1&category[]=2, then you can get the value of the parameter in the following way:

$categories = $_GET['category']; // 获取category参数的值，结果为[1,2]

3. For Parameter values ​​that need to be passed with special characters need to be encoded using the urlencode() function. For example:

// 当URL为 http://example.com/page.php?name=John&message=Hello world! 时
$name = $_GET['name']; // 获取name参数的值，结果为John
$message = $_GET['message']; // 获取message参数的值，结果为Hello world!

2. Processing of route resolution

In web applications, route resolution refers to the process of mapping URLs to corresponding handlers or codes. PHP provides multiple ways to implement route resolution processing. The following is a common implementation method:

1. Create a routing file, such as route.php:

<?php

$routes = [
    '/' => 'HomeController@index',
    '/about' => 'AboutController@index',
    '/contact' => 'ContactController@index',
];

2. In the main program, parse the URL and based on The configuration in the routing file calls the corresponding controller and method:

<?php

$uri = $_SERVER['REQUEST_URI']; // 获取当前请求的URI

if(isset($routes[$uri])){
    $route = $routes[$uri];
    $segments = explode('@', $route);
    $controller = $segments[0];
    $method = $segments[1];
    // 调用对应控制器的方法
    call_user_func(array(new $controller, $method));
}else{
    // 处理404页面
    echo "Page not found";
}

In the above example, when the user accesses different URLs, different controllers and methods will be called to process. For example, when accessing "/about", the index method of the AboutController class will be called.

It should be noted that this is just a simple implementation of route resolution. In actual development, a framework or library may be used to handle route resolution, providing more powerful and flexible functions.

Summary

This article introduces how PHP handles URL query parameters and route resolution. By processing URL query parameters, the parameter values ​​passed in the URL can be easily obtained and used. Through route resolution, URLs can be mapped to corresponding controllers and methods to implement the routing function of web applications. Understanding and mastering this knowledge will help develop more efficient and maintainable web applications.

The above is the detailed content of How does PHP handle URL parameters and routing?. For more information, please follow other related articles on the PHP Chinese website!