UserInput/docs/tutorial.txt

eZ Components - UserInput
~~~~~~~~~~~~~~~~~~~~~~~~~

.. contents:: Table of Contents

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

The UserInput component facilitates the secure handling of input data. With a
user-defined form definition, the component analyzes, filters and returns GET
and POST data. The component will not render forms to HTML from its definition, but only
handle incoming data. Filtering is done through PHP's filter_ extension;
accordingly, UserInput supports all filters and flags that this extension supports.


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

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

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


Basic usage
===========

The example in this section is separated into multiple parts to allow for
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 is an object of the ezcInputFormDefinitionElement class. 

The first parameter to the constructor is either
ezcInputFormDefinitionElement::REQUIRED for fields that *must* be submitted
(although they can be empty) or ezcInputFormDefinitionElement::OPTIONAL for
optional fields. The second parameter is the filter to use for the input
field. The filters are defined in PHP's filter_ extension, and can also be
retrieved by the PHP function filter_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 that are all required.
Two of them are strings (firstName and lastName), one is an integer (age) and
the last one is an e-mail address (email).

.. include:: tutorial_example_01_init.php
   :literal:

Here, we initialize the variables that are used to show the current value
and whether invalid data was submitted to the form. This is used later 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. Aside
from the ezcInputForm::hasGetData() method to verify if there is GET data
available, there is another method, ezcInputForm::hasPostData(), which does the
same thing but for POST data. Upon instantiation of the ezcInputForm object in
line 4, the component will parse the input data and make the input fields
available through the object. In case one of the required input variables does
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 (in 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 (in line 12). In
case the data for a field is 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 the default value in the input fields. If the data for one of
the fields is invalid, this will be shown next to the field.

More information
================

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

.. _filter: http://pecl.php.net/filter
.. _`filter documentation`: http://php.net/filter
.. _htmlspecialchars: http://php.net/htmlspecialchars


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