Laravel is a popular PHP framework that provides great flexibility and convenience when handling HTTP requests. In Laravel, request parameters refer to the data sent from the client to the server. They contain information entered by the user, such as data in the form and data in the query string. This article will introduce how to handle request parameters in Laravel, including obtaining request parameters, handling validation, setting default values, and some common use cases.

1. Obtain request parameters

In Laravel, you can use the "Request" class to obtain request parameters. The following are some commonly used methods for obtaining request parameters:

1. Get query string parameters: Use the input method or query method to obtain.

$name = $request->input('name');
$name = $request->query('name');

2. Get form parameters: Use the input method or get method to obtain. If you use POST request, you can use input method or post method to get it.

$name = $request->input('name');
$name = $request->get('name');
$name = $request->post('name');

3. Get routing parameters: Use the route method to get them.

$user_id = $request->route('user_id');

2. Request verification

When processing request parameters, it is usually necessary to verify the parameters to ensure the validity of the parameters. Laravel provides built-in validators to validate request parameters. The following are some common validation rules:

1.required: required field.

2.minimum: minimum value.

3.maximum: maximum value.

4.email: Email format.

5.numeric: Numeric type.

6.regex: Regular expression.

7.exists: Exists in the specified table.

The following is a simple example:

$validatedData = $request->validate([
    'name' => 'required',
    'email' => 'required|email',
    'age' => 'required|numeric|min:18',
]);

In the above example, it will be verified that the "name" and "email" fields are filled in and are valid email addresses, and "age" The field must be of numeric type and must be greater than or equal to 18. If validation fails, a "ValidationException" exception will be thrown.

3. Set default values

Sometimes, the request parameters may not be filled in. In order to prevent errors, setting default values ??is a good way. In Laravel, you can set a default value by passing a second parameter using the get method. For example:

$name = $request->get('name', 'John Doe');

In the above example, if the "name" field is not filled in, the default value is "John Doe".

4. Common use cases

The following are some common use cases:

1. File upload

Laravel provides a good file upload function, which can Get the uploaded file through the $request->file() method. For example:

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

if ($file->isValid()) {
    // 處理文件上傳
}

2. Processing JSON requests

In Laravel, you can obtain JSON type request parameters through the $request->json() method. For example:

$data = $request->json()->all();

3. Get the request method

Use the $request->method() method to get the request method. For example:

if ($request->method() === 'POST') {
    // 處理POST請求
}

4. Get the requested URL

Use the $request->fullUrl() method to get the complete URL address of the request. For example:

$url = $request->fullUrl();

5. Conclusion

Correctly handling request parameters in Laravel is very important, not only to improve the security of the website, but also to improve the readability and maintainability of the code. Through the introduction of this article, you should already know how to handle request parameters, validate request parameters, set default values, and some common use cases in Laravel.

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