The core of handling HTTP requests and responses in Laravel is to master the acquisition of request data, response return and file upload. 1. When receiving request data, you can inject the Request instance through type prompts and use input() or magic methods to obtain fields, and combine validate() or form request classes for verification; 2. Return response supports strings, views, JSON, responses with status codes and headers and redirect operations; 3. When processing file uploads, you need to use the file() method and store() to store files. Before uploading, you should verify the file type and size, and the storage path can be saved to the database.

Handling HTTP requests and responses in Laravel is the core part of building web applications. The framework itself provides very convenient tools to receive request data, process logic, and return appropriate response content. The key is to understand how the controller method receives the request object and how different types of responses are constructed.

Receive request data

Laravel's controller method can automatically inject Illuminate\Http\Request instance through type prompts, so that you can easily obtain user-submitted data.

For example, when you want to get a form submitted field:

 use Illuminate\Http\Request;

public function store(Request $request)
{
    $name = $request->input('name');
    $email = $request->input('email');
}

In addition to input() method, you can also use more intuitive magic methods:

 $email = $request->email;

In addition, verification request data is also common. Laravel provides two ways: one is to use $request->validate() directly in the controller; the other is to use a special form request class (Form Request). The latter is more suitable for complex verification scenarios and is more conducive to code reuse.

Tips: If you need to get all input data, you can use $request->all() , but be careful to avoid inserting directly into the database to prevent mass assignment vulnerabilities.

Return to the response content

Laravel supports various ways to return responses to the client. The easiest way is to directly return strings or views:

 return view('welcome');

If you want to return JSON data, you can use response()->json() :

 return response()->json([
    'status' => 'success',
    'data' => $user
]);

Sometimes you also need to set status codes or header information:

 return response('Hello', 200)
            ->header('Content-Type', 'text/plain')
            ->header('X-Header-One', 'Header-Value');

If it is a redirect operation, Laravel also has a simple method:

• Redirect to the named route: return redirect()->route('home');
• Redirect back to the previous page: return back();
• Redirect with input data: return redirect()->back()->withInput();

Process file upload

Laravel's request object can also easily handle the upload process when your form contains files. First make sure that the form uses enctype="multipart/form-data" and then obtain the uploaded file through file() method:

 if ($request->hasFile('avatar')) {
    $file = $request->file('avatar');
    $path = $file->store('avatars');
}

Laravel's file storage system is used here, which will be saved to storage/app/ directory by default. You can specify a disk drive (such as S3 or public):

 $path = $file->store('avatars', 's3');

After the upload is successful, the path is usually required to be saved to the database. For example:

 $user->avatar = $path;
$user->save();

Note: It is best to do some verification before uploading the file, such as limiting the size and type, which can be done in combination with $request->validate() .

Basically that's it. Master these three contents - obtaining request parameters, returning responses, and processing upload files, you can handle most common HTTP interactions freely in Laravel.

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