Learning Laravel from scratch: Detailed explanation of controller method invocation

Learning Laravel from scratch: Detailed explanation of controller method invocation

In the development of Laravel, controller is a very important concept. The controller serves as a bridge between the model and the view, responsible for processing requests from routes and returning corresponding data to the view for display. Methods in controllers can be called by routes. This article will introduce in detail how to write and call methods in controllers, and will provide specific code examples.

First, we need to create a controller. You can use the Artisan command line tool to generate a controller. Enter the following command on the command line:

php artisan make:controller TestController

This will generate a controller file named TestController in the app/Http/Controllers directory. Opening this file, we can see a basic controller structure:

<?php

namespace AppHttpControllers;

use IlluminateHttpRequest;

class TestController extends Controller
{
    //
}

Next, we write a method in the controller. Suppose we want to write a method called welcome that returns welcome information. Modify TestController as follows:

<?php

namespace AppHttpControllers;

use IlluminateHttpRequest;

class TestController extends Controller
{
    public function welcome()
    {
        return "欢迎使用Laravel！";
    }
}

Now that we have written a method named welcome, we need to register this method in the route. Open the routes/web.php file, where you can define the route and point it to the welcome method in TestController:

Route::get('/welcome', 'TestController@welcome');

Now we can call the welcome method in TestController by accessing the "/welcome" route and return "Welcome to Laravel!" This string.

In addition to basic GET requests, controller methods can also receive request parameters. For example, we can modify the welcome method of TestController to receive a parameter and return a welcome message that changes according to the parameters:

public function welcome(Request $request)
{
    $name = $request->input('name');
    return "欢迎使用Laravel，{$name}！";
}

The method of passing parameters in routing will also change. We can use the following method :

Route::get('/welcome/{name}', 'TestController@welcome');

By accessing "/welcome/John", you can get the welcome message "Welcome to Laravel, John!"

In actual development, we usually involve more complex business logic and data processing, and the controller methods will become more complex accordingly. For example, we may need to get data from the database and return it to the view. It is a common practice to call models in controller methods to implement database operations. The following is an example:

use AppModelsUser;

public function getUser($id)
{
    $user = User::find($id);
    return view('user.profile', ['user' => $user]);
}

In this example, we obtain the user data corresponding to $id through the User model and pass this user data to the view named profile. In the view we can use the Blade template engine to render data.

Through the above examples, I believe readers have a deeper understanding of the invocation of controller methods in Laravel. Mastering the writing and calling of controller methods will allow us to develop applications more efficiently and better implement business logic. I hope this article can help readers better understand Laravel, a popular PHP framework.

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