CodeIgniter 4 Validation Tutorial

Since v4.3.0, new Form helper functions validation_errors(), validation_list_errors() and validation_show_error() to display Validation Errors are added.

You can use the same View form file for a simple form and a form with redirect.

Requirement

• PHP 7.4 or later
• CodeIgniter 4.4

Setup

$ git clone https://github.com/kenjis/ci4-validation-tutorial.git
$ cd ci4-validation-tutorial/
$ composer install

$ php spark serve

Forms

Form1

This is a simple form:

• Navigate to http://localhost:8080/form1 (GET /form1)
  • Display the form1
• Submit (POST /form1)
  • Validation passes → Display success
  • Validation fails → Display form1 with Errors

Form2

This form is using redirect and withInput():

• Navigate to http://localhost:8080/form2 (GET /form2)
  • Display the form2
• Submit (POST /form2)
  • Validation passes → Display success
  • Validation fails → Redirect back → (GET /form2) Display form2 with Errors