HomePHP Page 4 - Building a PHP 5 Form Processor: Coding the Form Generator Module
Constructing forms programmatically: defining the “formGenerator” class - PHP
Most developers must deal with the job of developing robust data validation for forms on a regular basis. Nobody wants to write the same code over and over, so this article (the first of three in a series) will help you develop an extensible and reusable form validation package. By the end of the article, you will have all the relevant classes that integrate the generator module of the PHP form processor.
As a matter of fact, the two classes written above can’t do much on their own, if they’re not integrated within a new class that actually constructs web forms. Given this condition, I’ll write another additional class, which will be tasked with constructing programmatically the pertinent form. Its signature is shown below:
By studying the source code for the above class, it’s fairly easy to grasp its driving logic. Here, the “formGenerator” class behaves like a form element factory, which instantiates form objects and uses the features of polymorphism to fetch the corresponding (X)HTML markup of each of them (notice the use of the “getHTML()” method inside the class). In addition, the constructor performs some useful initialization tasks, such as setting up the values for the “action” and “method” properties of the form, and incidentally will assign default values to them if no parameters are passed to this method.
Now, after describing the initializing tasks of the constructor, turn your attention to the most relevant class methods. First, the “addElement()” method takes care of instantiating form objects, then calls their “getHTML()” method (again I strongly emphasize the use of polymorphism) and finally stores the returning (X)HTML code in the $this->html array. Definitely, this is an easy way to house progressively the markup code for the web form, as it’s being generated.
As you can see, the class also exposes the “addFormPart()” method, which comes in very handy for interspersing (X)HTML code within the form itself, and allows us to easily build the layout of form elements. Simple and efficient.
At this stage, I’ve gone through the makings of the form generator module, which, as you’ve seen, is responsible for creating form elements and programmatically constructing online forms. Additionally, this module exposes some basic client-side validation features that can be easily customized, in order to fit specific requirements. Hopefully, this first tutorial has helped provide you with a clear idea of how a PHP 5 form processor can be developed with minor hassles.
That’s about it for the moment. Throughout this first article, I’ve written all the relevant classes that integrate the generator module of the PHP form processor. Using the nice OOP capabilities of PHP 5, coding a form processing library is actually an instructive experience, particularly if you’re pretty new to object programming.
In the second tutorial, I’ll be diving into writing the “validator” module, which, as you might guess, will expose a bunch of methods aimed at performing robust server-side validation on online forms. Meet you in the next tutorial!