How to check if a file with <If ...> tag exists on Apache 2.4?

Question

I would like to check the existence of a file in httpd.conf for Apache 2.4.

I use the tag as follows:

<If "%{DocumentRoot}/maintenance.enable -f"> ...code to execute ... </If>

but my code is not very good, the Apache service does not want to start. I read a lot of manuals or documents on many sites, but did not find the answer :(

Please help me...

Answer 1

Read the Apache error log, this: <If "-f %{DOCUMENT_ROOT} . '/maintenance.enable'">