laravel_middleware_and_requests.md

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Laravel Middleware and Requests

• Middleware provides a way to filter HTTP requests entering your application.
• Requests encapsulate HTTP methods (GET, POST, DELETE, PATCH, PUT, etc.) and give you tools to work with them.

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Middleware

• Middleware functions are invoked before a request is sent to the server.
• They can be used for tasks like user authentication, input validation, or logging.

<?php

namespace App\Http\Middleware;

use Closure;

class ExampleMiddleware
{
    public function handle($request, Closure $next)
    {
        // Perform action before request sends
        $response = $next($request); // Call the next middleware
        // Perform action after response returns
        return $response;
    }
}

Learn more here

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Defining Middleware

• Middleware can be defined globally, on a route, or on a controller.

<?php

// Global middleware
protected $middleware = [
    \App\Http\Middleware\EncryptCookies::class,
    \Illuminate\Session\Middleware\StartSession::class,
    \Illuminate\View\Middleware\ShareErrorsFromSession::class,
    \App\Http\Middleware\VerifyCsrfToken::class,
    \Illuminate\Routing\Middleware\SubstituteBindings::class,
];

// Route middleware
Route::get('/', function () {
    //
})->middleware('example');

Learn more here

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Middleware Groups

• Middleware groups allow you to group several middleware under a single key to simplify routes and avoid repetition.

<?php

namespace App\Http\Middleware;

use Illuminate\Foundation\Http\Middleware\TransformsRequest;

class ExampleMiddlewareGroup
{
    protected $middleware = [
        TransformsRequest::class,
    ];
}

Learn more here

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Requests

• Illuminate\Http\Request represents an HTTP request.
• The request carries HTTP headers, cookies, and body content.

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class ExampleController extends Controller
{
    public function exampleAction(Request $request)
    {
        //
    }
}

Learn more here

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Request Methods

• You can access the HTTP verb of a request:

$request->method();

• Or check if the request is of a certain method:

$request->isMethod('post');

Learn more here

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Request Input

• To retrieve a single value from the request input, you can use the get method:

$value = $request->get('key');

• Or access input values by name:

$name = $request->input('user.name');

Learn more here

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Request Files

• To retrieve files from the request:

$file = $request->file('file_ud');

• To validate uploaded files:

$is_valid = $request->file('avatar')->isValid();

Learn more here

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Request Headers

• To retrieve a specific header from the request:

$value = $request->header('Content-Type');

• Or all headers:

$headers = $request->headers->all();

Learn more here

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Request Cookies

• To retrieve a specific cookie from the request:

$value = $request->cookie('ck_name');

• Or all cookies:

$cookies = $request->cookies->all();

Learn more here

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Request Query Parameters

• To retrieve a specific query parameter from the request:

$value = $request->query('key');

• Or all query parameters:

$query_params = $request->query();

Learn more here

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Request Validation

• Laravel provides a convenient way to validate incoming HTTP request data.

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class ExampleController extends Controller
{
    public function exampleAction(Request $request)
    {
        $validated = $request->validate([
            'title' => 'required|string|max:255',
            'body' => 'required|string',
        ]);
    }
}

Learn more here

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Conclusion

• Middleware provides a way to filter HTTP requests.
• Requests encapsulate HTTP methods and provide tools to work with them.
• Use Laravel's built-in features to filter & validate incoming requests.

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References

• Laravel Middleware Documentation
• Laravel Requests Documentation
• Laravel Validation Documentation

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