either INI or XML formats and includes a useful inheritance system for supporting different configuration
settings on different servers, such as production, staging and test.
Security is very much on the minds of every PHP developer worth his salt. Input data validation and
filtering is the key to a secure application. Zend_Filter and Zend_Validate are provided to help the developer
ensure that input data is safe for use in the application.
The Zend_Filter class provides a set of filters that typically remove or transform unwanted data from the
input as it passes through the filter. For example, an numeric filter would remove any characters that were not
numbers from the input and an HTML entities filter would convert the “<” character to the sequence “<”.
Appropriate filters can then be set up to ensure that the data is valid for the context it will be used in.
Zend_Validate provides a very similar function to Zend_Filter, except that it provides a yes/no answer to
the question “is this data what I expect?”. Validation is generally used to ensure that the data is correctly
formed, such as the data provided as an email address is actually an email address. In the case of failure,
Zend_Validate also provides a message in
