Request validation basics in Laravel - Mini Project: Build & Apply

Request validation basics

📖 Scenario: You are building a simple Laravel web application where users can submit their contact information through a form. To keep the data clean and safe, you need to validate the user input before saving it.

🎯 Goal: Build a Laravel controller method that validates a request with specific rules for name, email, and age fields.

📋 What You'll Learn

Create a controller method named store that accepts a Request object

Add validation rules for name, email, and age fields

Use Laravel's $request->validate() method for validation

Return the validated data as an array

💡 Why This Matters

🌍 Real World

Validating user input is essential in web applications to ensure data integrity and security before processing or saving it.

💼 Career

Understanding Laravel request validation is a key skill for backend developers working with Laravel to build robust and secure web applications.

1

Create the store method with a Request parameter

Create a public method called store inside a controller class that accepts a parameter named $request of type Request.

Laravel

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class ContactController extends Controller
{
    // Create the store method with Request parameter
    // Your code here
}

Hint

Define a public function named store that takes Request $request as input.

2

Define validation rules array

Inside the store method, create a variable named $rules that is an array with these exact keys and values: 'name' => 'required|string|max:255', 'email' => 'required|email', and 'age' => 'nullable|integer|min:18'.

Laravel

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class ContactController extends Controller
{
    public function store(Request $request)
    {
        // Create the validation rules array
        // Your code here
    }
}

Hint

Use an associative array with keys name, email, and age and their validation rules as strings.

3

Validate the request using $request->validate()

Use the $request->validate() method with the $rules array to validate the incoming data inside the store method. Store the result in a variable named $validatedData.

Laravel

 'required|string|max:255',
            'email' => 'required|email',
            'age' => 'nullable|integer|min:18'
        ];
        // Validate the request using $rules
        // Your code here
    }
}

Hint

Call $request->validate($rules) and assign the result to $validatedData.

4

Return the validated data

At the end of the store method, return the $validatedData variable.

Laravel

 'required|string|max:255',
            'email' => 'required|email',
            'age' => 'nullable|integer|min:18'
        ];
        $validatedData = $request->validate($rules);
        // Return the validated data
        // Your code here
    }
}

Hint

Use return $validatedData; to send back the validated input.

Practice

1. What is the main purpose of request validation in Laravel?

easy

A. To check user input early and ensure data is safe and correct

B. To speed up the server response time

C. To format the output HTML automatically

D. To connect to the database securely

Solution

1. Step 1: Understand request validation role

   Request validation checks user input before processing to avoid bad data.

2. Step 2: Identify main goal

   The main goal is to keep data safe and correct by stopping invalid input early.

3. Final Answer:

   To check user input early and ensure data is safe and correct -> Option A

4. Quick Check:

   Request validation = safe, correct input [OK]

Hint: Validation protects data by checking input early [OK]

Common Mistakes:

• Thinking validation speeds up server
• Confusing validation with output formatting
• Assuming validation manages database connections

2. Which of the following is the correct syntax to validate a request field named email as required and must be a valid email in a Laravel controller?

easy

A. $request->validate(['email' => 'required|email']);

B. $request->validate(['email' => 'email||required']);

C. $request->validate(['email' => 'required,email']);

D. $request->validate(['email' => ['required', email]]);

Solution

1. Step 1: Recall Laravel validation syntax

   Laravel uses pipe-separated strings for rules like 'required|email'.

2. Step 2: Check each option

   $request->validate(['email' => ['required', email]]);: syntax error ('email' not quoted in array). $request->validate(['email' => 'email||required']);: 'email||required' has empty invalid rule. $request->validate(['email' => 'required,email']);: uses comma which is invalid. $request->validate(['email' => 'required|email']);: correct pipe syntax.

3. Final Answer:

   $request->validate(['email' => 'required|email']); -> Option A

4. Quick Check:

   Pipe-separated rules = correct syntax [OK]

Hint: Use pipes '|' to separate validation rules in strings [OK]

Common Mistakes:

• Using commas instead of pipes
• Syntax errors in array rule lists
• Double pipes creating empty rules

3. Given this Laravel controller code snippet:

public function store(Request $request) {
    $validated = $request->validate([
        'age' => 'required|integer|min:18'
    ]);
    return $validated['age'];
}

What will be the output if the request sends age=20?

medium

A. Validation error: age is required

B. Validation error: age must be at least 18

C. null

D. 20

Solution

1. Step 1: Understand validation rules

   Field 'age' must be present, an integer, and minimum 18.

2. Step 2: Check input value

   Input age=20 meets all rules: present, integer, and >=18.

3. Step 3: Determine output

   Validation passes, so $validated['age'] returns 20.

4. Final Answer:

   20 -> Option D

5. Quick Check:

   Valid input returns value [OK]

Hint: Valid input passes and returns validated data [OK]

Common Mistakes:

• Assuming validation error for valid input
• Confusing min rule with max
• Expecting null when validation passes

4. Identify the error in this Laravel validation code:

public function update(Request $request) {
    $request->validate([
        'username' => 'required|min:5|max'
    ]);
}

medium

A. The 'required' rule cannot be combined with 'min'

B. The 'max' rule is missing a value, causing a syntax error

C. The 'min' rule should be 'min=5' instead of 'min:5'

D. The validate method should be called on the controller, not the request

Solution

1. Step 1: Review validation rules syntax

   Rules like 'min' and 'max' require a value after colon, e.g., 'max:10'.

2. Step 2: Identify error in code

   The 'max' rule is written without a value, which is invalid syntax.

3. Final Answer:

   The 'max' rule is missing a value, causing a syntax error -> Option B

4. Quick Check:

   Rules need values after colon [OK]

Hint: Always provide values for min/max rules after colon [OK]

Common Mistakes:

• Omitting values for min/max rules
• Using '=' instead of ':' in rules
• Calling validate on wrong object

5. You want to validate a request in Laravel where the password field is required, must be at least 8 characters, and must be confirmed by a matching password_confirmation field. Which validation rule set correctly enforces this?

hard

A. ['password' => 'required|confirmed', 'password_confirmation' => 'min:8']

B. ['password' => 'required|min:8', 'password_confirmation' => 'required']

C. ['password' => 'required|min:8|confirmed']

D. ['password' => 'required|min:8', 'password_confirmation' => 'same,password']

Solution

1. Step 1: Understand Laravel's confirmed rule

   The 'confirmed' rule checks if a matching field with '_confirmation' suffix exists and matches.

2. Step 2: Check each option

   ['password' => 'required|min:8|confirmed'] uses 'confirmed' with 'min:8' and 'required' on password only, which is correct. ['password' => 'required|min:8', 'password_confirmation' => 'required'] requires password_confirmation but does not check matching. ['password' => 'required|confirmed', 'password_confirmation' => 'min:8'] misplaces min:8 on confirmation. ['password' => 'required|min:8', 'password_confirmation' => 'same,password'] uses invalid 'password' rule.

3. Final Answer:

   ['password' => 'required|min:8|confirmed'] -> Option C

4. Quick Check:

   Use 'confirmed' rule for password confirmation [OK]

Hint: Use 'confirmed' rule to check matching confirmation field [OK]

Common Mistakes:

• Forgetting to add 'confirmed' rule
• Validating confirmation field separately
• Using 'same' instead of 'confirmed' rule