Form validation is an essential part of a web application to ensure user input is accurate, secure, and reliable. In this tutorial, we will learn how to implement form validation in CodeIgniter 4 using built-in validation rules as well as custom rules. This CodeIgniter 4 form validation tutorial will guide you step by step with examples of validating input fields like name, email, and age. You will learn how to handle form validation errors in CodeIgniter 4 and create user-friendly forms for your web applications.
We will develop a registration form and validate the form after submission. If validation fails, we will display validation error messages. We will also use callback validation by creating custom rules.
We will assume you have already got CodeIgniter 4 installed in your project root. All you have to do is run the below command from the command line. For our example, we installed it in D:/projects.
composer create-project codeigniter4/appstarter form
It creates a folder named 'form' in D:/projects and CodeIgniter 4 is installed in that folder.
If you want to know how to install and configure CodeIgniter 4, you can read the tutorial Install CodeIgniter 4 on XAMPP Server in Windows
Below is a screenshot of the registration page:
Folders and Files
As mentioned earlier, we have created a folder named 'projects' in D:\ drive and installed CodeIgniter 4 in the 'projects/form' folder. So, the project root directory is D:/projects/form.
We will have Controller - Candidate.php, Model - ModelCandidate.php and the view - register.php.
There is a CodeIgniter 4 custom validation rule for age checks. This is for age validation, as our form will accept ages between 18 and 40 only, we need to validate the age entered by the user.
Create a MySQL table
Our table name is 'candidates' in MySQL database.
Table: candidates
It stores details of all the candidates who completed registration.
Below are the columns in this table.
- candidate_id - Primary key and auto incremented candidate id
- name - Name of the candidate
- address - Address of the candidate
- email_id - Email Id of the candidate
- age - Age of the candidate
- registration_dt - Date of Registration
candidates.sql
CREATE TABLE `candidates` (
`candidate_id` int(11) NOT NULL,
`name` varchar(100) NOT NULL,
`address` varchar(200) NOT NULL,
`email_id` varchar(100) NOT NULL,
`age` smallint(6) NOT NULL,
`registration_dt` date NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
ALTER TABLE `candidates`
ADD PRIMARY KEY (`candidate_id`);
ALTER TABLE `candidates`
MODIFY `candidate_id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=1;
Create the view for registration (register.php)
We will create a registration form with input fields Name, Email Id, Address and Age. This CodeIgniter 4 tutorial is more about form validation. So, let's take a look at the code first:
app/Views/register.php
<!DOCTYPE html>
<html lang="en">
<head>
<title>Candidate Registration</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
<link rel="stylesheet" href="/assets/css/style.css">
</head>
<body>
<div class="container">
<h2>Candidate Registration</h2>
<p class="error "><?= $err_msg ?></p>
<p class="success"><?= $succ_msg ?></p>
<?php $validation = \Config\Services::validation(); ?>
<?= session()->getFlashdata('error') ?>
<form id ="frm" action = "register" method = "post">
<?= csrf_field() ?>
<div class="form-group col-md-12">
<label>Name</label>
<input type = "text" name="name" id = "name" class="form-control" maxlength="100" value="<?php echo set_value('name');?>" placeholder="Enter Your Name">
<span class="error"><?= esc($validation->getError('name'));?> </span>
</div>
<div class="form-group col-md-12">
<label>Email Id</label>
<input type = "text" name="email" id = "email" class="form-control" maxlength="100" value="<?php echo set_value('email');?>" placeholder="Enter Your Email">
<span class="error"><?= esc($validation->getError('email'));?> </span>
</div>
<div class="form-group col-md-12">
<label>Address</label>
<textarea name="addr" id = "addr" class="form-control" maxlength="200" placeholder="Enter Your Address" ><?php echo set_value('addr');?></textarea>
<span class="error"><?= esc($validation->getError('addr'));?> </span>
</div>
<div class="form-group col-md-12">
<label>Age <small>(Must be between 18 and 40 only)</small></label>
<input type = "number" name="age" id = "age" class="form-control" value="<?php echo set_value('age');?>" placeholder="Enter Your Age in Years">
<span class="error"><?= esc($validation->getError('age'));?> </span>
</div>
<div class="col-md-12 text-center">
<input type ="submit" name="signup" class="btn btn-primary" value="Submit">
</div>
</form>
</div>
</body>
</html>
You can see in line 15, we have used $validation = \Config\Services::validation(), this will load the validation settings with rulesets that we can use in our validation. For each input field, an error message will be displayed in case validation fails for that field. Once the form is submitted register() method of the Candidate controller is called.
Write Controller code (Candidate.php)
The controller will have an index() method to display the registration page and a register() method to process the submitted data. We will use the model ModelCandidate.php, so we need to create an instance of the model. See the code below at the beginning of the controller:
protected $model;
protected $uri;
protected $validation;
public function __construct() {
helper(['form', 'url']);
$this->uri = service('uri');
$this->validation = service('validation');
$this->model = new ModelCandidate();
}
public function index() {
$element['succ_msg'] = "";
$element['err_msg'] = "";
echo view('register',$element);
}
In the construct method, the 'form' and the 'url' helpers are loaded. 'uri' and 'validation' services are also loaded. Then an instance of the model is created. index() method is executed by default in a controller. In this method, it loads the view to display the registration form.
Controller Method register()
In this method, we will do CodeIgniter 4 input validation for the input fields in the form.
If the form is submitted, it validates the input fields using validation rules. If validation fails, it reloads the view with an error message displayed. But if all fields are validated successfully, this method inserts the data in the table using the model. Let's see the code for register() method.
if ($this->request->getMethod() === 'post') {
$rules = [
'name' => [
'label' => 'Name',
'rules' => 'trim|required',
],
'email' => [
'label' => 'Email Id',
'rules' => 'trim|required|valid_email|is_unique[candidates.email_id]',
],
'addr' => [
'label' => 'Address',
'rules' => 'required',
],
'age' => [
'label' => 'Age',
'rules' => 'required|ageCheck'
]
];
$errors = [
'name' =>[
'required' => 'You must enter a {field}'
],
'email' => [
'required' => 'You must enter an {field}',
'valid_email' => '{value} is not a valid email address',
'is_unique' => '{value} already registered'
],
'addr' => [
'required' => 'You must enter an {field}'
],
'age' => [
'required' => 'You must enter an {field}',
'ageCheck' => '{field} must be between 18 and 40',
],
];
if (!$this->validate($rules, $errors)) {
echo view('register',$element);
}
else {
// validations are successful, go for registration
$name = $this->request->getPost('name');
$email = $this->request->getPost('email');
$addr = $this->request->getPost('addr');
$age = $this->request->getPost('age');
$data = array('name'=>$name, 'address'=>$addr, 'email_id'=>$email, 'age'=>$age);
$result = $this->model->save($data);
if ($result){
$msg = 'Registration successful';
$element['succ_msg'] = $msg;
}
else{
$msg = "Error in Registration";
$element['err_msg'] = $msg;
}
echo view('register',$element);
}
}
else { // load the form
echo view('register',$element);
}
First, we defined the validation rules for each input field and then defined the validation error messages. The validate() method validates the form.
Just check for 'age' validation. We have used a custom rule 'ageCheck'. This is to validate the allowed range of valid ages. We will discuss how it is defined. $errors is for custom error messages in case validation fails.
If validation is successful, $this->model->save() method will insert the row into the database table and return true or false.
Age validation
For age validation, we need to create custom validation rule in Codeigniter4. See the code below in ProjectRules.php under app/CustomValidation. This is similar to the callback method used in CodeIgniter 3.
namespace App\CustomValidation;
class ProjectRules {
public function ageCheck(string $str) {
if (!empty($str)){
if ((int) $str <18 || (int) $str >40) {
return false;
}
else
return true;
}
return false;
}
}
It checks the value of the input if it falls between 18 and 40. If not, it returns false. Based on this, a validation error message is displayed in the form.
Write Model code (ModelCandidate.php)
Our model is very simple, it defines the table name and updatable columns.
<?php
namespace App\Models;
use CodeIgniter\Model;
class ModelCandidate extends Model{
protected $table = 'candidates';
protected $allowedFields = ['name','email_id','address','age', 'registration_dt'];
}
Stylesheet for all these views.
style.css
h2{
text-align: center;
margin-top: 50px;
}
p.success{
text-align: center;
color:green;
font-size: 20px;
}
p.error{
text-align: center;
color:red;
font-size: 20px;
}
.error{
color:red;
min-height: 20px;
font-size: 17px;
}
label{
font-weight: bold;
}
#frm {
margin: 5px auto;
padding-top: 21px;
padding-bottom: 40px;
border: 1px solid #09168d;
border-radius: 7px;
background: #fff;
width: 47%;
}
textarea.form-control{
resize: none !important;
height: 100px !important;
}
Routes
Update Routes file (app/Config/Routes.php) as below:
/*
* --------------------------------------------------------------------
* Router Setup
* --------------------------------------------------------------------
*/
$routes->setDefaultNamespace('App\Controllers');
$routes->setDefaultController('Candidate');
$routes->setDefaultMethod('index');
$routes->setTranslateURIDashes(false);
$routes->set404Override();
$routes->setAutoRoute(true);
/*
* --------------------------------------------------------------------
* Route Definitions
* --------------------------------------------------------------------
*/
// We get a performance increase by specifying the default
// route since we don't have to scan directories.
$routes->get('/', 'Candidate::index');
$routes->get('/register', 'Candidate::register');
$routes->post('/register', 'Candidate::register');
Test the Application
Before testing, make sure you update database setup file (app/Config/Database.php) with the MySQL database name you are using. I updated $default as below:
public $default = [
'DSN' => '',
'hostname' => 'localhost',
'username' => 'root',
'password' => '',
'database' => 'demo',
'DBDriver' => 'MySQLi',
'DBPrefix' => '',
'pConnect' => false,
'DBDebug' => (ENVIRONMENT !== 'production'),
'charset' => 'utf8',
'DBCollat' => 'utf8_general_ci',
'swapPre' => '',
'encrypt' => false,
'compress' => false,
'strictOn' => false,
'failover' => [],
'port' => 3306,
];
Also, update .env to set the environment to development. This file is in root directory.
# CI_ENVIRONMENT = production
CI_ENVIRONMENT = development
Test the Application
Type php spark serve from your project root and enter. This will start the server in port 8080.
Run http://localhost:8080/ in the browser. This will open the home page.
Test the validation for all the fields. Try to submit an incomplete form. You should see the proper validation messages.
Test using Apache web server
If you are using XAMPP make sure your root folder is xampp/htdocs/form, i.e., you have to install CI4 in this folder. Open httpd-vhosts.conf file in Notepad from xampp\apache\conf\extra folder. Add the below line at the end of it.
DocumentRoot "D:/xampp/htdocs/form/public"
Save it and restart the Apache service from the XAMPP controller.
Now in app/Config/App.php, update base url as below:
public $baseURL = 'http://localhost/';
Open the browser and run http://localhost. You will see the page as displayed below:
Do the same testing described above.
That's it! Our development and testing are done for this CodeIgniter4 application.
Conclusion
In this tutorial, we learned how to implement form validation in CodeIgniter 4. We created a CodeIgniter 4 project and used a registration form to validate input fields. We also learned how to create custom rules and display validation error messages.
Please write your comments/questions in the Comments section below. Your questions, doubts and suggestions are always welcome.
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