Add an Input or Output directive to obj.conf to instruct the server to insert your filter into the filter stack. The format of the directive is as follows:
Directive fn=insert-filter filter="filter-name" [name1="value1"]...[nameN="valueN"]
Directive is Input or Output.
filter-name is the name of the filter, as passed to filter_create, to insert.
nameN="valueN" are the names and values of parameters that are passed to the filter's insert filter method.
Filters that process incoming data should be inserted using an Input directive. Filters that process outgoing data should be inserted using an Output directive.
To ensure that your filter is inserted whenever a client sends a request, add the Input or Output directive to the default object. For example, the following portion of obj.conf instructs the server to insert a filter named example-replace and pass it two parameters, from and to:
<Object name="default"> Output fn=insert-filter filter="example-replace" from="Old String" to="New String" ... </Object>