This module controls that the conditions in the requests is fullfilled. For example a request may specify that the answer only is of interest if the content is unchanged since last retrieval. Or if the content is changed the range-request shall be converted to a request for the whole file instead.
If a client sends more then one of the header fields that restricts the servers right
to respond, the standard does not specify how this shall be handled.
httpd will control each field in the following order and if one of the fields not
match the current state the request will be rejected with a proper response.
1.If-modified
2.If-Unmodified
3.If-Match
4.If-Nomatch
Uses the following EWSAPI interaction data, if available:
{real_name,{Path,AfterPath}}
Exports the following EWSAPI interaction data, if possible:
{if_range,send_file}
Uses the following EWSAPI functions: