eZ components - UserInput
~~~~~~~~~~~~~~~~~~~~~~~~~

.. contents:: Table of Contents

Introduction
============

This component makes secure handling of input data easier. With a user defined
form definition the component analyses, filters and returns GET and POST data.
The component will not render forms to HTML from its definition, but only
handles incoming data. The filtering is done through PHP's filter_ extension
and the component supports all filters and flags that this extension supports.


Class overview
==============

ezcInputForm
  Is the class that validates the definition, processes the form data and
  provides functionality for accessing the submitted data.

ezcInputFormDefinitionElement
  The container class that wraps around the definition for each form element.
  It contains whether the field is optional or required, the filter name and
  optional flags for the filter.


Basic Usage
===========

The example in this section is cut in multiple parts to allow easier
explanation. 

.. include:: tutorial_example_01_def.php
   :literal:

In the lines above we prepare a definition array that defines our form. A
definition array consists of an associative array where the key is the input
field name and the value an object of the ezcInputFormDefinitionElement class. 

The first parameter to the constructor is either
ezcInputFormDefinitionElement::REQUIRED for fields that *have* to be submitted
(although they can be empty) or ezcInputFormDefinitionElement::OPTIONAL for
optional fields. The second parameter is the filter to use for this input
field. The filters are defined in PHP's filter_ extension, and can also be
retrieved by the PHP function input_filters_list(). The third optional
parameter contains flags to the filter. Those are documented in the 
`filter documentation`_.

In the definition above we define four input fields, which are all required.
Two of them are strings (firstName and lastName), one is an integer (age) and
the last one an e-mail address (email).

.. include:: tutorial_example_01_init.php
   :literal:

Here we just initialize the variables that are used to show the current value
and whether invalid data was submitted to the form. This is later used to
render the form.

.. include:: tutorial_example_01_process.php
   :literal:

In line 2 we check whether there was GET data submitted to this script. Besides
the ezcInputForm::hasGetData() method to verify if there is GET data available
there is another method, ezcInputForm::hasPostData(), which does the similar
thing but then for POST data. Upon instantiation of the ezcInputForm object in
line 4 the component will parse the input data and makes the input fields
available through the object. In case one of the required input variables did
not exist in the input data this instantiation will throw an
ezcInputFormFieldNotFoundException exception.

In lines 6 to 20 we loop over all elements from the definition and check (line
10) whether the field has valid data. When there is valid data available we
retrieve the value from the $form object through a property (line 12) and in
case the data for a field was invalid we fetch the raw data with the
ezcInputForm::getUnsafeRawData() function, encode that with htmlspecialchars_
and set the parameter with the name "property\_<fieldname>" to the encoded raw
data. We also record in the "warning\_<fieldname>" variable if the field has
invalid data.


.. include:: tutorial_example_01_form.php
   :literal:

The last part of this example renders the form. If previous data was submitted
it will be shown as default value in the input fields. If the data for one of
the fields was invalid it will show that next to the field as well.

More Information
================

The filters and its parameters are documented are documented in the
`filter documentation`_.

.. _filter: http://pecl.php.net/filter
.. _`filter documentation`: http://files.derickrethans.nl/filter_extension.html
.. _htmlspecialchars: http://php.net/htmlspecialchars


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