Form request classes in Laravel - Step-by-Step Execution

Concept Flow - Form request classes

User submits form

↓

FormRequest class intercepts

↓

Validate input rules

↓

Controller

↓

Show errors

When a user submits a form, the FormRequest class checks input against rules. If valid, data goes to the controller. If invalid, user sees errors.

Execution Sample

Laravel

public function rules()
{
    return [
        'email' => 'required|email',
        'password' => 'required|min:8'
    ];
}

Defines validation rules for email and password fields in a FormRequest class.

Execution Table

Step	Action	Input Data	Validation Result	Next Step
1	Receive form data	{email: '[e-mail]', password: 'secret123'}	Not checked yet	Validate input
2	Check 'email' field	'[e-mail]'	Passes 'required' and 'email' rules	Check next field
3	Check 'password' field	'secret123'	Passes 'required' and 'min:8' rules	All fields valid
4	All validations passed	N/A	Valid	Send data to controller
5	Controller processes data	Valid data	N/A	Complete request
6	If invalid input example	{email: '', password: '123'}	Fails 'email' required and 'password' min:8	Redirect back with errors

💡 Validation stops when all rules pass or any rule fails, then proceeds accordingly.

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
email	[e-mail]	[e-mail]	[e-mail]	Valid
password	secret123	secret123	secret123	Valid
validation_status	Not checked	Partial pass	All pass	Valid

Key Moments - 2 Insights

Why does the form redirect back instead of calling the controller?

If any validation rule fails (see step 6 in execution_table), Laravel automatically redirects back with error messages instead of running controller code.

How does Laravel know which rules to apply?

The rules() method in the FormRequest class returns the validation rules array (shown in execution_sample), which Laravel uses to check each input field.

Visual Quiz - 3 Questions

Look at the execution_table at step 3, what is the validation result for the password field?

A Fails 'required' rule

B Passes 'required' and 'min:8' rules

C Fails 'min:8' rule

D Not checked yet

💡 Hint

Check the 'Validation Result' column at step 3 in the execution_table.

At which step does Laravel decide to send data to the controller?

A Step 2

B Step 6

C Step 4

D Step 1

💡 Hint

Look for the step where 'All validations passed' and 'Send data to controller' appear in the execution_table.

If the email field is empty, how does the execution_table change?

A Step 2 shows failure on 'email' required rule

B Step 3 shows failure on 'password' rule

C Step 4 sends data to controller anyway

D No change, validation passes

💡 Hint

Refer to step 6 in execution_table where invalid input causes failure on 'email' required rule.

Concept Snapshot

Form Request Classes in Laravel:
- Create a FormRequest class to handle validation.
- Define rules() method returning validation rules.
- Laravel auto-validates input before controller runs.
- On failure, redirects back with errors.
- On success, controller receives validated data.

Full Transcript

When a user submits a form in Laravel, the FormRequest class intercepts the data. It runs the rules defined in the rules() method to check each input field. If all fields pass validation, the data is sent to the controller for processing. If any field fails, Laravel automatically redirects the user back to the form with error messages. This process helps keep controller code clean and validation centralized. The execution table shows each step: receiving data, checking each field, deciding if data is valid, and either continuing or redirecting. Variables like email and password hold input values and their validation status updates as checks run. Understanding this flow helps beginners see how Laravel manages form validation smoothly.

Practice

1. What is the main purpose of a Form Request class in Laravel?

easy

A. To define routes for the application

B. To create database migrations automatically

C. To manage user authentication sessions

D. To organize and handle validation rules separately from controllers

Solution

1. Step 1: Understand the role of Form Request classes

   Form Request classes are designed to keep validation rules and authorization logic separate from controller code.

2. Step 2: Identify the main benefit

   This separation helps keep controllers clean and improves code organization and security.

3. Final Answer:

   To organize and handle validation rules separately from controllers -> Option D

4. Quick Check:

   Form Request = Validation organization [OK]

Hint: Form Requests separate validation from controllers [OK]

Common Mistakes:

• Confusing Form Requests with database migrations
• Thinking Form Requests handle authentication
• Assuming Form Requests define routes

2. Which of the following is the correct way to create a Form Request class using Artisan CLI?

easy

A. php artisan create:request UserRequest

B. php artisan make:formrequest UserRequest

C. php artisan make:request UserRequest

D. php artisan generate:form UserRequest

Solution

1. Step 1: Recall the Artisan command for Form Requests

   The correct Artisan command to create a Form Request class is make:request.

2. Step 2: Match the command with the options

   php artisan make:request UserRequest uses php artisan make:request UserRequest, which is the correct syntax.

3. Final Answer:

   php artisan make:request UserRequest -> Option C

4. Quick Check:

   Artisan command for Form Request = make:request [OK]

Hint: Use 'make:request' to create Form Requests [OK]

Common Mistakes:

• Using 'make:formrequest' instead of 'make:request'
• Using 'create:request' which is invalid
• Using 'generate:form' which does not exist

3. Given this Form Request class snippet, what will $request->validated() return if the input is ['name' => 'John', 'age' => 20]?

class UserRequest extends FormRequest {
    public function rules() {
        return [
            'name' => 'required|string',
            'age' => 'required|integer|min:18'
        ];
    }
}

medium

A. {'name' => 'John', 'age' => 20}

B. {'name' => 'John'}

C. ValidationException error

D. Empty array []

Solution

1. Step 1: Check validation rules against input

   The rules require 'name' as a string and 'age' as an integer >= 18. Input has 'name' = 'John' (string) and 'age' = 20 (integer, >=18), so validation passes.

2. Step 2: Understand what validated() returns

   The validated() method returns all input fields that passed validation, so it returns the full input array.

3. Final Answer:

   {'name' => 'John', 'age' => 20} -> Option A

4. Quick Check:

   Valid input returns full validated data [OK]

Hint: Validated returns all fields passing rules [OK]

Common Mistakes:

• Assuming partial data is returned
• Expecting an error when input is valid
• Confusing validated() with all() method

4. Identify the error in this Form Request class that causes validation to always pass even with invalid input:

class ProductRequest extends FormRequest {
    public function rules() {
        return [
            'price' => 'required|numeric|min:0'
        ];
    }

    public function authorize() {
        return false;
    }
}

medium

A. The authorize method returns false, blocking validation

B. The rules method is missing required fields

C. The min:0 rule is invalid for numeric fields

D. The class name should be ProductFormRequest

Solution

1. Step 1: Understand the authorize() method role

   The authorize() method controls if the request is allowed. Returning false denies the request before validation.

2. Step 2: Effect of returning false in authorize()

   When authorize() returns false, Laravel automatically denies the request, so validation rules are not applied and the request fails authorization.

3. Final Answer:

   The authorize method returns false, blocking validation -> Option A

4. Quick Check:

   authorize() false blocks request [OK]

Hint: authorize() must return true to run validation [OK]

Common Mistakes:

• Ignoring authorize() method effect
• Thinking min:0 is invalid for numeric
• Believing class name affects validation

5. You want to create a Form Request that validates an optional email field but only if it is present, and it must be a valid email format. Which rule should you use in the rules() method?

hard

A. 'email' => 'nullable|email'

B. 'email' => 'sometimes|email'

C. 'email' => 'required|email'

D. 'email' => 'present|email'

Solution

1. Step 1: Understand optional validation rules

   To validate a field only if it is present in the input, Laravel uses the sometimes rule.

2. Step 2: Compare rules for optional email

   nullable allows null values and skips subsequent rules if null; present requires the field to exist even if empty; sometimes applies validation only if the field is sent.

3. Final Answer:

   'email' => 'sometimes|email' -> Option B

4. Quick Check:

   Use sometimes for optional fields [OK]

Hint: Use sometimes to validate only if field exists [OK]

Common Mistakes:

• Using required which forces presence
• Using nullable which requires field present but can be null
• Using present which requires field always present