Form Validation Class

The Form Validation class allows you to validate form input data easily and cleanly. It handles checking for required fields, verifying data type, length, and uniqueness, as well as sanitizing and preparing data for database insertion.

Overview

Typical form validation process:

A form is displayed.
The user fills it and submits it.
If invalid, the form is redisplayed with error messages and old values.
If valid, the data is processed (e.g. saved to a database).

LavaLust provides a dedicated Form Validation library to simplify this process.

Form Validation Tutorial

You will need three parts:

A form view containing the input fields
A success view shown after successful submission
A controller to process and validate the data

The Form

Create myform.php in your app/views/ directory:

<html>
<head>
   <title>My Form</title>
</head>
<body>
<?php $LAVA = lava_instance(); ?>
<?php echo $LAVA->form_validation->errors(); ?>

<form action="<?php echo site_url('form');?>" method="post">
   <h5>Username</h5>
   <input type="text" name="username" size="50" />

   <h5>Password</h5>
   <input type="text" name="password" size="50" />

   <h5>Password Confirm</h5>
   <input type="text" name="passconf" size="50" />

   <h5>Email Address</h5>
   <input type="text" name="email" size="50" />

   <div><input type="submit" value="Submit" /></div>
</form>

</body>
</html>

The Success Page

Create formsuccess.php in app/views/:

<html>
<head>
   <title>Form Success</title>
</head>
<body>
   <h3>Your form was successfully submitted!</h3>
</body>
</html>

The Controller

Create Form.php in app/controllers/:

<?php
class Form extends Controller {

   public function index()
   {
      $this->call->library('form_validation');

      // Modern validation (recommended)
      if ($this->form_validation->validate([
         'username|Username' => 'required|min_length[5]|max_length[20]',
         'password|Password' => 'required|min_length[8]',
         'passconf|Confirm Password' => 'required|matches[password]',
         'email|Email Address' => 'required|valid_email'
      ]))
      {
         $this->call->view('formsuccess');
      }
      else
      {
         $this->call->view('myform');
      }
   }
}

Trying It Out

Visit your form in the browser:

example.com/index.php/form/

If you submit without filling fields, validation will fail and errors will be displayed.

The validate() method returns TRUE only if all validation rules pass.

Setting Validation Rules (Modern)

Rules are defined using a pipe-separated string:

$this->form_validation->validate([
   'username|Username' => 'required|min_length[5]|max_length[20]',
   'password|Password' => 'required|min_length[8]',
   'passconf|Confirm Password' => 'required|matches[password]',
   'email|Email Address' => 'required|valid_email'
]);

Use | to separate rules
Use [value] to pass parameters
Use field|Label to customize field names in error messages

Setting Custom Error Messages

$this->form_validation->validate([
   'username|Username' => 'required|min_length[5]'
], [
   'username' => [
      'required' => 'Username is required!',
      'min_length' => 'Username must be at least 5 characters'
   ]
]);

Using submitted()

You can check if the form is submitted:

if ($this->form_validation->submitted()) {
   // form was submitted
}

Legacy / Fluent Style (Optional)

The old chaining method is still supported:

$this->form_validation
   ->name('username')
      ->required()
      ->min_length(5)
      ->max_length(20)
   ->name('password')
      ->required()
      ->min_length(8)
   ->name('passconf')
      ->required()
      ->matches('password')
   ->name('email')
      ->valid_email();

if ($this->form_validation->run() == FALSE) {
   $this->call->view('myform');
} else {
   $this->call->view('formsuccess');
}

Notes

validate() is the recommended approach
It automatically resets previous errors
Cleaner and easier to scale
run() is mainly used for fluent style

The name() method selects the input field to validate. Chained methods like required(), min_length(), matches() apply validation rules to it.

Available Methods

Method	Description
`name($field)`	Selects the input field by its name attribute to apply rules on.
`pattern($name, $custom_error)`	Validates using a built-in pattern. Possible values: `url, alpha, words, alphanum, int, float, tel, file, folder, date_dmy, date_ymd, email`.
`custom_pattern($regex, $custom_error)`	Validates against a custom regex pattern.
`required($custom_error)`	Ensures the field is not empty.
`matches($field, $custom_error)`	Ensures the value matches another field’s value.
`differs($field, $custom_error)`	Ensures the value differs from another field’s value.
`is_unique($table, $field, $str, $custom_error)`	Checks if the value does not exist in a database table column.
`exact_length($length, $custom_error)`	Ensures the string length is exactly this number.
`min_length($length, $custom_error)`	Ensures the string length is at least this number.
`max_length($length, $custom_error)`	Ensures the string length does not exceed this number.
`valid_email($custom_error)`	Ensures the value is a valid email format.
`alpha($custom_error)`	Allows only alphabetic characters.
`alpha_space($custom_error)`	Allows alphabetic characters and spaces.
`alpha_numeric($custom_error)`	Allows only alphanumeric characters.
`alpha_numeric_space($custom_error)`	Allows alphanumeric characters and spaces.
`alpha_numeric_dash($custom_error)`	Allows alphanumeric characters and dashes.
`numeric($custom_error)`	Allows only numeric values.
`greater_than($value, $custom_error)`	Ensures the value is greater than the given number.
`greater_than_equal_to($value, $custom_error)`	Ensures the value is greater than or equal to the given number.
`less_than($value, $custom_error)`	Ensures the value is less than the given number.
`less_than_equal_to($value, $custom_error)`	Ensures the value is less than or equal to the given number.
`in_list($array, $custom_error)`	Ensures the value exists within the given array list.
`run()`	Runs the validation. Returns TRUE if no errors found.
`errors()`	Returns a string of all validation errors. Empty string if none.
`submitted()`	Checks if the form was submitted. Returns TRUE if submitted, FALSE otherwise.
`reset()`	Resets all validation errors and previous input values.
`validate($rules, $custom_errors)`	Validates using an array of rules. Returns TRUE if all pass, FALSE if any fail.
`rules($rules, $custom_errors)`	Sets validation rules using an array. Does not run validation.

Note

Each validation method supports an optional $custom_error parameter to override the default error message.

Error Display

To show validation errors in your form, include this line in your view:

<?php echo $this->form_validation->errors(); ?>

It will return a string of all validation errors. If there are none, it returns an empty string.