Zend_Filter supplies a set of commonly needed filters, but developers will often need to write custom
filters for their particular use cases. The task of writing a custom filter is facilitated by
implementing Zend_Filter_Interface
.
Zend_Filter_Interface
defines a single method, filter()
, that may be
implemented by user classes. An object that implements this interface may be added to a filter chain
with Zend_Filter::addFilter()
.
The following example demonstrates how to write a custom filter:
class MyFilter implements Zend_Filter_Interface { public function filter($value) { // perform some transformation upon $value to arrive on $valueFiltered return $valueFiltered; } }
To add an instance of the filter defined above to a filter chain:
$filterChain = new Zend_Filter(); $filterChain->addFilter(new MyFilter());