The class that we are going to create within CI will simply add a math question that the user will have to enter correctly to continue. This is useful to stop bots from mass submitting information to your forms.

The class we are going to write is only very short and simple, but it will give you an idea of how to create classes for your own projects.

Creating the new class

First of all we need to create the file for the class, navigate to libraries then create a file called math_question.php.

All we are going to do within this class is generate two random numbers that will be added together.

<?php
class math_question {
 
	function questionOne()
	{
		// generate a random number between 0 - 10
		$num = rand() % 10;
		return $num;
	}
 
	function questionTwo()
	{
		$num = rand() % 10;
		return $num;
	}
 
}

This is all we will be doing for the code within the class.

Using the class within a form

To use this class in our controller we load it like so:

$this->load->library('math_question');

We will also be using form validation and sessions to check if the user has entered the correct answer.

$this->load->library('form_validation');
$this->load->library('session');

We need to set questionOne and questionTwo in variables so we can assign them to a temporary flash session and because they will be passed into the view.

$questionOne = $this->math_question->questionOne();
$questionTwo = $this->math_question->questionTwo();
 
$this->session->set_flashdata('questionOne', $questionOne);
$this->session->set_flashdata('questionTwo', $questionTwo);
 
$data['math_question'] = "What is {$questionOne} + {$questionTwo}?";

To check that the answer that is wrote in is correct we use the callback method in our form validation to call a function that we create that will check the users input against the flash data.

This is how we set our form validation:

$this->form_validation->set_rules('math_question', 'Math Question', 'callback_math_question');

Then we check if the validation has been executed:

if($this->form_validation->run() == FALSE)
{
	$this->load->view('contact/form', $data);
 
}
else
{
	echo "success";
}

Now we need to create our function that is called upon validation of the form:

function math_question()
{
	$user_answer = $this->input->post('math_question');
	$questionOne = $this->session->flashdata('questionOne');
	$questionTwo = $this->session->flashdata('questionTwo');
 
	$correct_answer = $questionOne + $questionTwo;
 
	if($user_answer != $correct_answer)
	{
		$this->form_validation->set_message('math_question', 'Your answer to the math question was incorrect');
		return FALSE;
	} else {
		return TRUE;
	}
}

This will check if what the user has input is correct against a temporary flash session.

Here is all of the controller code in full:

<?php
class Contact extends Controller {
 
	function index()
	{
		$this->load->library('form_validation');
		$this->load->library('math_question');
		$this->load->library('session');
 
		$questionOne = $this->math_question->questionOne();
		$questionTwo = $this->math_question->questionTwo();
 
		$this->session->set_flashdata('questionOne', $questionOne);
		$this->session->set_flashdata('questionTwo', $questionTwo);
 
		$data['math_question'] = "What is {$questionOne} + {$questionTwo}?";
 
		$this->form_validation->set_rules('math_question', 'Math Question', 'callback_math_question');
 
 
		if($this->form_validation->run() == FALSE)
		{
			$this->load->view('contact/form', $data);
 
		}
		else
		{
			echo "success";
		}
	}
 
 
 
	function math_question()
	{
		$user_answer = $this->input->post('math_question');
		$questionOne = $this->session->flashdata('questionOne');
		$questionTwo = $this->session->flashdata('questionTwo');
 
		$correct_answer = $questionOne + $questionTwo;
 
		if($user_answer != $correct_answer)
		{
			$this->form_validation->set_message('math_question', 'Your answer to the math question was incorrect');
			return FALSE;
		} else {
			return TRUE;
		}
	}
 
}

Create the view

The last thing we need to do is create the view. Goto views and create a folder called contact, within that folder create a file called form.php.

Here is the code for form.php

<?php
echo validation_errors();
echo form_open('contact');
?>
Name: <input type="text" name="name" /> <br />
<?=$math_question?> <br />
Answer: <input type="text" name="math_question" /> <br />
<input type="submit" name="submit" value="Send!" />
<?php
echo form_close();
?>

On the first line we output the validation errors if there is any, on the second line we use the form helper to open the form tags and likewise for the bottom line where we close the form. $math_question is the variable that is passed in from the controller.

Post your thoughts

Let us know what you think of the tutorial and share your thoughts and contributions below in the comments.

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The plugin that I'm going to show you how to create within this post is a plugin that I created for MakeUseOf.

Creating plugins for WP is relatively easy and uses actions to call functions that are included in pages within the main WP files. To learn more about creating plugins for WP go here.

Ok so lets get started with creating the plugin.

When creating a plugin for WP make sure that you include your own unique word or acronym to your functions so that they don't conflict with any other plugins that may be installed.

Because I created this for MakeUseOf the acronym I use is MUO and then AF because I named the plugin author footer so every function within this plugin begins with MUO_AF.

So to start our plugin we add this

Here is where we add the name of our plugin, a description, your name and the version number of your plugin.

The next bit of code that we add is the register_activation_hook and register_deactivation_hook so that when the plugin is activated and deactivated the code within functions that we will create in our next step will be executed.

We're now going to create two functions called MUO_AF_activate and MUO_AF_deactivate so that the register hooks work correctly.

In the next step we will write code that will be called and displayed within the Your Profile page in the admin-cp.

When the Update Profile button is clicked the information from the previous bit of code will be retrieved in the next bit of code and the database will be updated.

The code we will write now is the code that will grab the contents of the post and then attach the authors signature to the end of that post.

We will now add the functions to actions, this is the most important part of the code because without this none of the functions would be called and nothing would happen.

Then at the end of the file close the php tags with

I have not been very descriptive in this tutorial of what the actual code within the plugin is doing because I created this tutorial wanting to show people the basics bit of code that are needed to call functions and make a plugin work.

I hope that you have learnt something by reading this tutorial and feel free to post a comment with your thoughts on this post.

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