mod_headers is not enabled by default

[Galen Charlton]

The Apache module mod_headers is not enabled by default in a new Evergreen installation. As a consequence, various directives in the stock eg_vhost.conf are never activated. The one that can really matter is this one:

  <Directory "@localstatedir@/web/eg2/en-US">
      FallbackResource /eg2/en-US/index.html
      <Files "index.html">
        <IfModule mod_headers.c>
          Header set Cache-Control "no-cache, no-store, must-revalidate"
          Header set Pragma "no-cache"
          Header set Expires 0
        </IfModule>
      </Files>
  </Directory>

If mod_headers is not active, the Angular staff client application's index page defaults to a cache period of 24 hours, which means that updates to the Angular app might not be picked up by the browser after an upgrade right away.

Evergreen 3.6+

[Galen Charlton (gmc)]

Patches are available in the following branch:

working/user/gmcharlt/lp1944765_enable_mod_headers / https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/gmcharlt/lp1944765_enable_mod_headers

[Jason Boyer (jboyer)]

Tested on Stretch and mod_headers was enabled after running Makefile.install as expected. Signoff is here: https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/jboyer/lp1944765_mod_headers_signoff / working/user/jboyer/lp1944765_mod_headers_signoff

[Chris Sharp (chrissharp123)]

Pushed to master with an additional commit to add this to the new Debian 11 "bullseye" Makefile.install script. Thanks, Galen and Jason!

[Chris Sharp (chrissharp123)]

Pushed the non-bullseye commit to 3.6 and 3.7.