Request validation basics in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What happens when a Laravel request fails validation?

Consider a Laravel controller method that uses $request->validate() with rules. What is the default behavior if the validation fails?

Laravel

public function store(Request $request) {
    $validated = $request->validate([
        'name' => 'required|string',
        'email' => 'required|email'
    ]);
    // ... store logic
}

A Laravel automatically redirects back with error messages and old input.

B The controller method returns null and does nothing.

C Laravel throws a fatal error and stops the application.

D The request continues and the controller stores the data anyway.

💡 Hint

Think about how Laravel helps users fix form errors by showing messages.

When validation fails, Laravel automatically redirects the user back to the previous page. It flashes the validation errors and old input data to the session so the user can correct mistakes.

📝 Syntax

intermediate

Which validation rule syntax is correct for requiring a numeric age over 18?

Choose the correct Laravel validation rule string to require an age field that must be numeric and at least 18.

A 'age' => 'required|numeric|min:18'

B 'age' => 'required|number|min:18'

C 'age' => 'required|integer|min18'

D 'age' => 'required|numeric|min18'

💡 Hint

Look for the correct Laravel rule names and syntax for minimum values.

The correct rules are numeric to ensure a number and min:18 to require a minimum value of 18. The other options use invalid rule names or syntax.

❓ state_output

advanced

What is the value of $validated after validation passes?

Given this Laravel controller code, what does $validated contain after validation?

Laravel

public function update(Request $request) {
    $validated = $request->validate([
        'title' => 'required|string|max:255',
        'content' => 'nullable|string'
    ]);
    return $validated;
}

A Null if any optional fields are missing.

B The original Request object with all input data.

C A JSON string of all request data.

D An array with only the validated fields and their values from the request.

💡 Hint

Think about what $request->validate() returns after success.

The validate() method returns an array containing only the fields that passed validation with their values from the request.

🔧 Debug

advanced

Why does this Laravel validation code cause a syntax error?

Identify the syntax error in this validation rules array:

Laravel

public function store(Request $request) {
    $request->validate([
        'email' => 'required|email',
        'password' => 'required|min:8|max:20',
        'age' => 'nullable|numeric|min:18'
    ]);
}

A The 'nullable' rule cannot be combined with 'numeric'.

B The 'min:18' rule is invalid for numeric fields.

C Missing comma after the 'password' rule line causes a syntax error.

D The 'email' rule must be last in the array.

💡 Hint

Look carefully at the commas between array elements.

In PHP arrays, each element must be separated by a comma. The missing comma after the 'password' line causes a syntax error.

🧠 Conceptual

expert

Which option best explains Laravel's Form Request validation advantage?

Laravel offers Form Request classes for validation. What is the main advantage of using Form Requests over inline $request->validate() calls?

A Form Requests disable validation errors and always accept input.

B Form Requests separate validation logic from controllers, improving code organization and reuse.

C Form Requests run validation on the client side before submitting forms.

D Form Requests automatically fix invalid input data without developer code.

💡 Hint

Think about code organization and maintainability.

Form Requests encapsulate validation rules and authorization logic in dedicated classes, keeping controllers clean and enabling reuse.