MVC pattern in PHP

MVC (Model-View-Controller) is a classic software design pattern that is widely used in Web development. As a popular server-side language, PHP also uses the MVC pattern extensively.

MVC pattern divides the application into three parts:

1. Model: handles all things related to data, including data acquisition, saving and verification.
2. View (View): Displays data to users and handles user interactive requests and responses.
3. Controller: Receive user requests, call the corresponding models and views to process the requests, and return the results to the user.

Using the MVC pattern can separate different parts of the application, improving the maintainability and scalability of the code. At the same time, the MVC model also complies with the "single responsibility principle", making the code clearer and more concise.

In PHP, there are many popular frameworks, such as Laravel, Yii, CodeIgniter, etc., which all adopt the MVC pattern.

Let’s take the Laravel framework as an example to introduce the MVC pattern in PHP:

1. Model

In Laravel, model usually refers to To represent tables in a database, each model class inherits from the Eloquent class. Using Eloquent can easily perform database operations, including inserts, updates, deletes, and queries.

For example, to operate the user table (users), you can create a User model class:

<?php

namespace App;

use IlluminateDatabaseEloquentModel;

class User extends Model
{
    //
}

In the User model class, you can define some methods to provide more convenient operations. For example, you can define a findUserById method to find a user based on the user ID:

public function findUserById($id)
{
    return $this->find($id);
}

2. View (View)

In Laravel, the view is usually generated by the Blade template engine Generated. The Blade template engine provides rich template syntax to easily build dynamic HTML pages.

For example, to display the user list page, you can create a userList.blade.php view file:

@foreach ($users as $user)
    <li>{{ $user->name }}</li>
@endforeach

In the controller, pass the user list data to the view to generate a dynamic HTML page:

public function userList()
{
    $users = User::all();

    return view('userList', ['users' => $users]);
}

3. Controller

In Laravel, the controller is responsible for receiving user requests, calling the corresponding models and views to handle the requests, and The results are returned to the user.

For example, to handle requests for user list pages, you can create a UserController controller:

<?php

namespace AppHttpControllers;

use IlluminateHttpRequest;
use AppUser;

class UserController extends Controller
{
    public function userList()
    {
        $users = User::all();

        return view('userList', ['users' => $users]);
    }
}

In the above sample code, by inheriting the Controller class, the UserController controller can use the one provided by Laravel Some convenience methods, such as the view method to generate views.

Summary

The MVC pattern is widely used in PHP and can help us separate the application into three parts to achieve code maintainability and scalability.

In Laravel, the MVC pattern can be used to conveniently perform database operations and view generation, and combine them together through controllers to handle user requests. Mastering the MVC pattern can help us develop web applications more efficiently.

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