🛡️ How Laravel Helps You Filter Bad Data

Stop Dirty Data: Laravel Validation Tips You Can’t Ignore

In any modern web application, validating user input is not just a best practice—it's essential. Whether you're building a small blog or a massive enterprise API, Laravel makes input validation elegant, powerful, and flexible.

✅ What is Request Validation?

Request validation is the process of ensuring that incoming data is in the expected format before processing it. Laravel provides a fluent, expressive interface for defining validation rules directly within your controllers, form requests, or even custom classes.

---

🚀 Why Validation is Important

Here are just a few reasons why validation is non-negotiable:

• Security: Prevent malicious input like SQL injection or XSS attacks.

• Data Integrity: Keep your database clean and consistent.

• User Experience: Provide clear error messages when something goes wrong.

• Reliability: Avoid processing incomplete or incorrect data.

---

🧠 Laravel Validation Strategies

Laravel gives us multiple ways to handle validation. Let’s explore each with examples and when to use them:

1. Inline Validation in Controllers (Quick & Simple)

Add validation logic directly inside the controller:

public function store(Request $request)
{
    $validated = $request->validate([
        'name' => 'required|string|max:255',
        'email' => 'required|email|unique:users,email',
    ]);

    // Continue with your logic...
}

2. Form Request Validation (Recommended)

Use php artisan make:request StoreUserRequest

class StoreUserRequest extends FormRequest
{
    public function rules(): array
    {
        return [
            'name' => 'required|string|max:255',
            'email' => 'required|email|unique:users,email',
        ];
    }

    public function authorize(): bool
    {
        return true; // add permission logic if needed
    }
}

In your controller:

public function store(StoreUserRequest $request)
{
    $validated = $request->validated();
}

💬 Customize the Error Message

add in StoreUserRequest

public function messages()
{
    return [
        'name.required' => 'Please provide your name.',
        'name.min' => 'Your name must be at least :min characters.',
        'email.required' => 'We need your email address.',
        'email.email' => 'This is not a valid email format.',
        'email.unique' => 'This email is already registered.',
        'password.required' => 'A password is mandatory.',
        'password.min' => 'Password must be at least :min characters.',
        'password.confirmed' => 'Passwords do not match.',
    ];
}

---

🧪 How to Add Custom Validation Rule

Create a custom rule called AlphaSpace that ensures a field only contains letters (a–z) and spaces. We'll apply this rule to a user's full name field.

🧩 Step 1: Generate the Custom Rule

php artisan make:rule AlphaSpace

This will create a file at:

app/Rules/AlphaSpace.php

🧩 Step 2: Define the Rule Logic

Open AlphaSpace.php and update it like this:

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class AlphaSpace implements Rule
{
    public function passes($attribute, $value): bool
    {
        // Allow only letters and spaces
        return preg_match('/^[a-zA-Z\s]+$/', $value);
    }

    public function message(): string
    {
        return 'The :attribute may only contain letters and spaces.';
    }
}

🧩 Step 3: Use the Rule in a Form Request

In RegisterUserRequest.php

use App\Rules\AlphaSpace;

public function rules(): array
{
    return [
        'full_name' => ['required', new AlphaSpace],
        'email' => 'required|email|unique:users,email',
        'password' => 'required|string|min:8|confirmed',
    ];
}

🧩 Step 4: Use the Request in Controller

use App\Http\Requests\RegisterUserRequest;

public function register(RegisterUserRequest $request)
{
    $validated = $request->validated();

    // You can now safely use $validated['full_name']
}

🧪 Example Inputs

---

✅ Benefits of Custom Rules

• Encapsulates logic in a reusable class

• Makes your validation cleaner and modular

• Great for domain-specific validation (e.g., policy number, PAN, GSTIN, etc.)

---

✅ Benefits of Using Laravel Validation

• 🚫 Prevents bad data from entering your system

• 💡 Clear and readable syntax

• 📦 Reusable with Form Requests

• 🔧 Customizable with custom rules

• 🔄 Automatically returns JSON errors for APIs

---

🧘 Wrapping Up

In this article, we covered how to implement and organize request validation effectively in Laravel. You learned:

• ✅ Inline Validation
  A quick and simple method perfect for small tasks, one-off features, or prototyping.

• 📄 Form Request Validation
  A clean and reusable approach ideal for larger applications, keeping your controllers slim and focused.

• 🧩 Custom Validation Rules
  A powerful way to enforce domain-specific or business-critical logic that goes beyond built-in Laravel rules.