A Workflow Based Multi-Form Approach for Zend Framework

Zend Framework (ZF) is a great application framework to build your website. Regardless of what site you are building – simple or complex – ZF will be your friend. However, ZF is not perfect and there are still some things that I really miss, for instance, an easy method to build workflow based multi-forms.

Warning! I need your input!

Please be warned: currently, I am thinking about the design of such a workflow based multiform approach. I didn’t start implementing yet! Everything that I post in this article is only a proposal or draft version and most of all it is a RFC (Requests for Comments)!

Hence, I really would appreciate your input. Please let me know, what you think about this approach…

What and Why?

What the heck do I mean with “Workflow Based Multi-Form Approach for Zend Framework”? Well, actually, I would like to have an easy method to define a set of forms and how they are linked up regarding their control- and data flow. Let me give you a simple example. Imagine a web shop where users can buy [insert your favorite gadget here]. After they selected whatever they want to buy, they click on a “buy now” button.

As soon as they clicked on this button, a simple workflow starts: first, the user has to enter some personal data (name, address, etc). After that, another form will popup where she can select the method of payment (credit card or bank transfer). In case she selects credit card, the next form will collect all the necessary credit card data; if she selects bank transfer the next form will collect all the necessary bank account details. The last step will show all the details and ask here to confirm the purchase.

In this simple example, we would need five different forms plus a method to define the logic. Of course, you could simple use the actions of your controller to implement the logic – and in this simple example, everything else would probably be an overhead. However, if you’ll have to deal with a whole bunch of such workflows there should be a more convenient (and stable) way to deal with this.

How?

The basic idea is to specify all your workflows using an XML file. The most important requirements are:

• The system has to be able to deal with several workflows
• Each workflow consists of a setup section and one or more forms
• Forms will not be specified in the XML file, instead you should be able to (re)use your Zend_Form classes
• Each form may consist of several submit buttons
• For each submit button you may specify:
  1. An action which will be triggered if the user clicks on the button. Each specified “on-submit-action” may consist of a condition, which will allow you to define something like: if user entered value A then trigger action X
  2. A form, which will be the next form in this workflow. Each specified “on-submit-form” may consist of a condition, which will allow you to define something like: if user entered value A then trigger action X

The XSD

If you would like to have a look at the XSD you may download the XML Schema Definition here… (please, right click on the link and select “Save Target As…”)

An XML Example

The XML corresponding to our example described above, would look like this:

<?xml version="1.0"?>
<mffConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://www.web-punk.com/mff.xsd">
 <workflows>
   <workflow id="firstwf">
     <setup>
        <!-- Path where your forms can be found.      -->
        <!-- If not set, default will be used:        -->
        <!-- APPLICATION_PATH/application/models/Form -->
        <formpath>P:\Path\to\your\Forms</formpath>
        <!-- DEBUG: not used yet                      -->
        <debug>true</debug>
     </setup>
     <forms>
        <form id="personalData">
           <!-- class name of the form. If not set,   -->
           <!-- default = Model_Form_[id] will be used -->
           <className>Model_Form_persData</className>
           <!-- Validate form on leave? Default = true -->
           <validateOnLeave>true</validateOnLeave>
           <buttons>
              <button id="next">
                 <!-- if user clicks next button, goto form payMethod -->
                 <toForm>payMethod</toForm>
              </button>
           </buttons>
        </form>
        <form id="payMethod">
           <className>Model_Form_payMethod</className>
           <buttons>
              <button id="back">
                 <toForm>personalData</toForm>
              </button>
              <button id="next">
                 <!-- if user clicks next button and $value='creditcard', goto form ccData -->
                 <toForm condition="$value = 'creditcard'">ccData</toForm>
                 <!-- if user clicks next button and $value='banktransfer', goto form baData -->
                 <toForm condition="$value = 'banktransfer'">baData</toForm>
              </button>
           </buttons>
        </form>
        <form id="ccData">
           <className>Model_Form_ccDetails</className>
           <buttons>
              <button id="back">
                 <toForm>payMethod</toForm>
              </button>
              <button id="next">
                 <toForm>confForm</toForm>
              </button>
           </buttons>
        </form>
        <form id="baData">
           <className>Model_Form_baDetails</className>
           <buttons>
              <button id="back">
                 <toForm>payMethod</toForm>
              </button>
              <button id="next">
                 <toForm>confForm</toForm>
              </button>
           </buttons>
        </form>
        <form id="confForm">
           <className>Model_Form_form2</className>
           <buttons>
              <button id="back">
                 <!-- if user clicks back button and $value = 'creditcard', goto form ccData -->
                 <toForm condition="$value = 'creditcard'">ccData</toForm>
                 <!-- if user clicks back button and $value = 'banktransfer', goto form baData -->
                 <toForm condition="$value = 'banktransfer'">baData</toForm>
              </button>
              <button id="next">
                 <toAction>finishOrder</toAction>
              </button>
           </buttons>
        </form>
     </forms>
   </workflow>
 </workflows>
</mffConfig>

How to use this stuff?

The last question that I would like to briefly discuss is how you would use this approach in your ZF application.

The first step would definitely be to build you forms as usual using Zend_Form, i.e. create a class that basically looks like this:

class Model_Form_form1 extends Zend_Form
{
    public function init()
    {
        $userEmail = new Zend_Form_Element_Text('user_email', array(
        	'label' => 'Your email address',
            'required' => false
        ));

        $btnSubmit = new Zend_Form_Element_Button('submit', array(
            'label' => 'Next',
            'type' => 'submit'
        ));        

        // Add filters and validators...

        // Add elements to form
        $this->addElements(array(
            $userEmail, $btnSubmit
        ));       

        // Add decorators...
	}
}

After you created all your forms, you could use an action to start the workflow:

class IndexController extends Zend_Controller_Action
{
	/**
	 * your index action...
	 *
	 * @return void
	 */
	public function indexAction()
	{
		// init MFF
		$mff = new MFF_MultiFormFlow();
		// start form with ID personalData in workflow with ID exampleWorkflow
		$mff->run('exampleWorkflow', 'personalData');
		// is data valid in all forms?
		if ($mff->isValid()) {
			dosomething($mff->getData());
		}
	}
}

As stated above, this is only an idea of how you could use this approach. I haven’t started implementing yet, so your input is welcome and valuable

• Bookmark on Delicious
• Digg this post
• Recommend on Facebook
• Share with Stumblers
• Tweet about it