Laravel 10 Validation With Example

in this article, we will explore the various ways of validating in Laravel with examples. We will create a custom rule and use it to validate input. The Laravel provides several different approaches to validate your application’s incoming data.

Laravel Framework

Laravel is an open-source PHP web application framework that is used for developing web applications and websites. It was created by Taylor Otwell and was first released in 2011.

It is widely used in web development for building various applications, from simple websites to complex web applications.

What’s Validation Rules:

Laravel offers a comprehensive set of data validation rules, which can be customized or leveraged from Laravel’s built-in rules. Laravel’s validation system is rule-based, allowing you to specify rules for each field.

The common rules are "required," "email," and "numeric“.

You can use Laravel’s inbuilt validate method for all incoming HTTP requests. This method serves to check whether the specified rules are satisfied, proceeding with the next steps, or displaying an error message in case of rule violation.

You can get all pre-defined rules from Laravel rules.

Validation Rules in Single String

You can define all rules for each field in a single string:

$validated = $request->validate([
        'employee_name' => 'required|unique:posts|max:255',
        'dept' => 'required',
    ]);

Validation Rules in Arrays

You can also define validation as arrays of rules instead of using a single string separated by '|'.

$validatedData = $request->validate([
    'employee_name' => ['required', 'unique:posts', 'max:255'],
    'dept' => ['required'],
]);

Stopping On First Validation Failure

Sometimes, We need to stop the validation process if the initial rule fails. Laravel offers the 'bail' rule for this purpose, ensuring that validation stops if any preceding validation fails.

$request->validate([
    'employee_name' => 'bail|required|unique:posts|max:255',
    'dept' => 'required',
]);

How to Validate Nested Data in Laravel

We can also define nested data in validation. You may specify these fields in your validation rules using “dot” syntax:

$request->validate([
    'employee_name' => 'required|unique:posts|max:255',
    'dept_details.name' => 'required',
    'dept_details.id' => 'required',
]);

How To Display The Validation Errors Message

Let’s display the error message when validation fails. Laravel provides $errors variable is made available to all views within your application through the 'Middleware\ShareErrorsFromSession' middleware, which is included in the web middleware group.

It’s part of web middleware so it is available on Laravel Blade template view:

@if ($errors->any())
    <div class="alert alert-danger">
        <ul>
            @foreach ($errors->all() as $error)
                <li>{{ $error }}</li>
            @endforeach
        </ul>
    </div>
@endif

Creating Custom Validation Rules

We have used 'validation' method to define validation rules for incoming requests. Let’s add our custom validation rules to this method. Create a ‘lowercase’ rule and attach to the validation method. This rule will be responsible for ensuring the employee_name is lowercase.

We need to register our custom validation rule in the AppServiceProvider.

Create a lowercase rule by using the following command:

php artisan make:rule LowerCase

This command creates a LowerCase file in the app/Rules folder.

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class LowerCase implements Rule
{
    /**
     * Create a new rule instance.
     *
     * @return void
     */    public function __construct()
    {
        //
    }

    /**
     * Determine if the validation rule passes.
     *
     * @param  string  $attribute
     * @param  mixed  $value
     * @return bool
     */    public function passes($attribute, $value)
    {
        //
    }

    /**
     * Get the validation error message.
     *
     * @return string
     */    public function message()
    {
        return 'The validation error message.';
    }
}

In the above file, we have two main methods:

passes()– We’ll write logic here to validate the string in lowercase.
message()– This method will display the error message if the rule is failed.

Updated file:

<?php

namespace App\Rules;

use Illuminate\Contracts\Validation\Rule;

class LowerCase implements Rule
{
    /**
     * Create a new rule instance.
     *
     * @return void
     */    public function __construct()
    {
        //
    }

    /**
     * Determine if the validation rule passes.
     *
     * @param  string  $attribute
     * @param  mixed  $value
     * @return bool
     */    public function passes($attribute, $value)
    {
        return preg_match('/^[a-z]+$/', $value);
    }

    /**
     * Get the validation error message.
     *
     * @return string
     */    public function message()
    {
        return 'The :attribute must contain only lowercase letters.';
    }
}

We have defined regex to validate input values in lowercase. The error message for this custom rule is defined in the message() method

Now, We can use our custom validation rule in a controller method or in a form request.

use App\Rules\LowerCase;

// Inside a controller method or form request
public function store(Request $request)
{
    $validatedData = $request->validate([
        'employee_name' => ['required', new LowerCase],
    ]);

    // Rest of your code
}

In the above code, the 'employee_name' field is validated using the Lowercase rule, which ensures that it contains only lowercase letters.

Let’s register our custom validation rule in the AppServiceProvider. We can do this in the boot method using the Validator::extend method.

// Inside the AppServiceProvider's boot method
use Validator;

Validator::extend('custom_rule', function ($attribute, $value, $parameters, $validator) {
    // Define your custom validation logic here
    return true; // Return true if validation passes, false otherwise
});

Conclusion:

We have learned how to use simple validation methods in your Laravel application, We have also defined inbuilt rules as well as created custom validation rules. You can also display error messages using middleware in your view file.