Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

To C, or Not to C

DZone's Guide to

To C, or Not to C

If you've ever had to configure Apache you've likely had to deal with httpd.conf files. Ever wonder why some IfModule constructs have a .c but others don't? Read on to find out more.

· Web Dev Zone ·
Free Resource

Bugsnag monitors application stability, so you can make data-driven decisions on whether you should be building new features, or fixing bugs. Learn more.

I've edited httpd.conf files for years now, and hadn't given much thought to why some “IfModule” constructs have a .c and some don’t. But then, I was editing a config and it was a mix of .c and non-.c constructs, so it niggled me as to why.

Consider the following:

LoadModule headers_module modules/mod_headers.so

This is split into two parts:

  • Module Identifier – headers_module – This is the module name. If in doubt, Google the module and get the name from the documentation.
  • Source File – mod_headers.c – This is the file name with a c extension.

We can then look at the “IfModule” documentation which gives the syntax:

<IfModule [!]module-file|module-identifier> ... </IfModule>

Putting this together we can use either the module identifier (headers_module):

<IfModule mod_headers.c>
  <filesMatch "\.(ico|jpe?g|png|gif|swf)$">
    Header set Cache-Control "max-age=2592000, public"
  </filesMatch>
  <filesMatch "\.(css)$">
    Header set Cache-Control "max-age=604800, public"
  </filesMatch>
  <filesMatch "\.(js)$">
    Header set Cache-Control "max-age=216000, private"
  </filesMatch>
</IfModule>

Or the source file (mod_headers.c):

<IfModule headers_module>
  <filesMatch "\.(ico|jpe?g|png|gif|swf)$">
    Header set Cache-Control "max-age=2592000, public"
  </filesMatch>
  <filesMatch "\.(css)$">
    Header set Cache-Control "max-age=604800, public"
  </filesMatch>
  <filesMatch "\.(js)$">
    Header set Cache-Control "max-age=216000, private"
  </filesMatch>
</IfModule>

Which Is Better?

None are better—the best option is to choose one approach and stick to it. I prefer the module-file name as it is easier to reconcile to my modules directory.

References

http://httpd.apache.org/docs/current/mod/mod_headers.html

http://httpd.apache.org/docs/2.4/mod/core.html#ifmodule

Monitor application stability with Bugsnag to decide if your engineering team should be building new features on your roadmap or fixing bugs to stabilize your application.Try it free.

Topics:
directory ,config ,modules ,apache ,conf

Published at DZone with permission of

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}