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In Form submission validation is one of the major functionality we need to attach. Validation is either from client side and/or from server side as well. As we are in CodeIgniter 4 section, we will see Email validation rules in codeigniter 4.
In CodeIgniter 4, there are several form validation properties we have. So here, we will see about all email related validations like required, a valid email format and also we will see already existence of email address in database.
Also we have Mobile validation step by step guide in CodeIgniter 4 Click here to go.
Note*: For this article, CodeIgniter v4.1 setup has been installed. May be when you are seeing, version will be updated. CodeIgniter 4.x still is in development mode.

Let’s get started.
Download & Install CodeIgniter 4 Setup
We need to download & install CodeIgniter 4 application setup to system. To set application we have multiple options to proceed. Here are the following ways to download and install CodeIgniter 4 –
- Manual Download
- Composer Installation
- Clone Github repository of CodeIgniter 4
Complete introduction of CodeIgniter 4 basics – Click here to go. After going through this article you can easily download & install setup.
Here is the command to install via composer –
$ composer create-project codeigniter4/appstarter codeigniter-4
Assuming you have successfully installed application into your local system.
Settings Environment Variables
When we install CodeIgniter 4, we have env file at root. To use the environment variables means using variables at global scope we need to do env to .env
Open project in terminal
$ cp env .env
Above command will create a copy of env file to .env file. Now we are ready to use environment variables.
CodeIgniter starts up in production mode by default. Let’s do it in development mode. So that while working if we get any error then error will show up.
# CI_ENVIRONMENT = production // Do it to CI_ENVIRONMENT = development
Now application is in development mode.
Application Routes Configuration
To configure application routes, we need to open up the file Routes.php from /app/Config. This is the main routes config file where we will do all routes of application.
//.. Other route $routes->match(["get", "post"], "add-student", "Student::addStudent");
View File – Create User Form
As, we have taken fields as name, email, mobile. So with respective with these fields we need to set the user layout. Views templates will be created inside /app/Views/add-student.php
Inside this view file, at top header we have used session() service to collect session temporary data to show flash message. Flash message we will send from controller in keys of success and error.
<?php // To print error messages if(isset($validation)){ print_r($validation->listErrors() ); } ?> <form action="<?= base_url('add-student') ?>" method="post"> <p> Name: <input type="text" name="name" placeholder="Enter name"/> </p> <p> Email: <input type="email" name="email" placeholder="Enter email"/> </p> <p> Mobile: <input type="text" name="mobile" placeholder="Enter mobile"/> </p> <p> <button type="submit">Submit</button> </p> </form>
- We will submit this form to controller. At controller end we will add form validation rules.
- print_r($validation->listErrors() ); It prints all errors at once. But in case if we want single error per line
To Check any input field has any error or not
<p> Email : <input type="email" name="email" class="<?= ($validation->hasError('email')) ? 'is-error' : '' ?>"/> </p>
Here, inside above code we are checking the field error, it exists then we are adding a class into input field with the email field of is-error.
Print any specific field error
if ($validation->hasError('email')){ echo $validation->getError('email'); // $validation is sent from controller }
Application Controller Settings
Controller is the functional file. Firstly let’s load a helper at Parent Controller i.e BaseController.php. This file is in /app/Controllers folder.
Search helpers in BaseController and load “url” into helpers.
protected $helpers = [‘url’];
After loading this url helper, we will able to use site_url() and base_url() in Controllers & Views else we should have some error.
We will create application controller at /app/Controllers. Let’s create Student.php inside the given folder. Open project into terminal and type this spark command.
$ php spark make:controller Student
Write the following code into /app/Controllers/Student.php
<?php namespace App\Controllers; use App\Models\StudentModel; class Student extends BaseController { public function addStudent(){ if($this->request->getMethod() == "post"){ $rules = [ "name" => "required", "email" => "required|valid_email|is_unique[users.email]|min_length[6]", "mobile" => "required", ]; $messages = [ "name" => [ "required" => "Mobile number required" ], "email" => [ "required" => "Email required", "valid_email" => "Email address is not in format", "is_unique" => "Email address already exists" ], "mobile" => [ "required" => "Mobile Number is required" ], ]; if (!$this->validate($rules, $messages)) { return view("add-student", [ "validation" => $this->validator, ]); }else{ // rest code to save data into database } } return view("add-student"); } }
- if ($this->request->getMethod() == “post”) Checking request type
- $rules = []; Define form validation rules
- $messages = [] Define custom messages
- if (!$this->validate($rules, $messages)) {} Validating add student form
- “email” => “required|valid_email|is_unique[users.email]|min_length[6]” All email validation rules. required It checks email should be required, valid_email Email address pattern should be valid pattern, is_unique Email address should be unique in database, min_length Minimum length of email address should be not less than 6 characters.
More about validations over different different input fields, you can visit official document of validations of CodeIgniter 4.
We hope this article helped you to fix email validation rules in codeigniter 4 in a very detailed way.
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Find More on CodeIgniter 4 here
- CodeIgniter 4 Cookie Helper Tutorial
- CodeIgniter 4 CRUD Application Tutorial
- CodeIgniter 4 CRUD REST APIs Tutorial
- CodeIgniter 4 CSRF Token in AJAX Request
- Database Query in CodeIgniter 4 Tutorial
- CodeIgniter 4 Ajax Form Data Submit
- CodeIgniter 4 Form Validation Tutorial
- CodeIgniter 4 Image Upload with Form Tutorial
- Multi language in CodeIgniter 4 Tutorial
- Stripe Payment Gateway Integration in CodeIgniter 4
- CodeIgniter 4 CSRF Token Tutorial
- CodeIgniter 4 Basics Tutorial
- CodeIgniter 4 Spark CLI Commands Tutorial
- Migration in CodeIgniter 4 Tutorial
- Seeders in CodeIgniter 4 Tutorial
Hi, I am Sanjay the founder of ONLINE WEB TUTOR. I welcome you all guys here to join us. Here you can find the web development blog articles. You can add more skills in web development courses here.
I am a Web Developer, Motivator, Author & Blogger. Total experience of 7+ years in web development. I also used to take online classes including tech seminars over web development courses. We also handle our premium clients and delivered up to 50+ projects.
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