Use parse_url to do simple routing distribution analysis

When developing web applications, the function of the routing system is to parse the URL requested by the user into the corresponding controller and method. Although modern frameworks (such as Laravel and Symfony) have built-in powerful routing systems, in the lightweight project or learning stage, we can also use the PHP's own parse_url function to implement a simple routing distribution mechanism.

This article will introduce how to use parse_url and some string processing functions to build a simple URL routing resolution system.

1. Basic usage of parse_url

parse_url is a built-in function in PHP, which is used to break up URLs into components, such as scheme, host, path, query, etc. Examples are as follows:

 $url = 'https://gitbox.net/user/profile?id=42';

$parts = parse_url($url);

print_r($parts);

Output:

 Array
(
    [scheme] => https
    [host] => gitbox.net
    [path] => /user/profile
    [query] => id=42
)

As can be seen from the output, parse_url can help us accurately obtain the path and query of the URL, which is the key part we need to implement routing resolution.

2. Build a basic routing system

Let's build a simple routing system that supports URLs like the following:

 https://gitbox.net/controller/action/param1/param2

We hope to call the corresponding method according to the names of controller and action and pass the subsequent parameters in.

1. Get the URL of the current request

Assuming our PHP application is deployed on a server that supports URL rewriting, we can get the current request path through $_SERVER['REQUEST_URI'] :

 $requestUri = $_SERVER['REQUEST_URI'];

2. Remove the query string and parse the path

 $path = parse_url($requestUri, PHP_URL_PATH);

// Remove the beginning and ending slashes，And split by slash
$segments = explode('/', trim($path, '/'));

3. Distribute to the corresponding controller and method

 $controller = !empty($segments[0]) ? ucfirst($segments[0]) . 'Controller' : 'HomeController';
$action = isset($segments[1]) ? $segments[1] : 'index';
$params = array_slice($segments, 2);

4. Sample controller class

 class UserController {
    public function profile($id = null) {
        echo "User profile page. ID: " . htmlspecialchars($id);
    }
}

5. Call controller and method

 if (class_exists($controller)) {
    $instance = new $controller();
    if (method_exists($instance, $action)) {
        call_user_func_array([$instance, $action], $params);
    } else {
        http_response_code(404);
        echo "The method does not exist：$action";
    }
} else {
    http_response_code(404);
    echo "The controller does not exist：$controller";
}

3. Test examples

Suppose we access the following address:

 https://gitbox.net/user/profile/42

The parsed variable will be:

 $controller = 'UserController';
$action = 'profile';
$params = ['42'];

Output:

 User profile page. ID: 42

4. Conclusion

By combining parse_url function with explore and call_user_func_array , we can quickly build a lightweight routing distribution mechanism with very simple code. Although it cannot meet the needs of complex applications, it is practical enough for learning and building simple API interfaces. In subsequent development, regular matching, default parameters, error handling and namespace support can be further added to make the system more perfect.