# Requires mod_expires to be enabled.
<IfModule mod_expires.c>
  # Enable expirations.
  ExpiresActive On

  # Cache all files for 2 weeks after access (A).
  ExpiresDefault A1209600

  # Do not cache dynamically generated pages.
  ExpiresByType text/html A1

  # But static HTML files can use the 2 week cache also.
  <IfModule mod_headers.c>
    <FilesMatch "\.(html?)$">
      Header set Cache-Control max-age=1209600
    </FilesMatch>
  </IfModule>
</IfModule>

<IfModule mod_headers.c>
  # Set E-tags for other files based on modified time and size. We exclude the
  # INode here because we use multiple web-servers that will assign a different
  # INode for anything not on the NFS mount.
  <LocationMatch "^/sites/">
    # Files within modules and themes have a 30 second "internal" lifetime
    # before they are retrieved and updated by Varnish again.
    Header append Cache-Control s-maxage=30
    # Assemble the ETag based on modified time and file size, but not INode.
    FileETag MTime Size
  </LocationMatch>

  # Set E-tags for files in the file directory. INode can be used in the hash
  # here because all files are hosted on an NFS mount.
  <LocationMatch "^/files/">
  # Assemble the standard ETag for shared NFS files.
  FileETag INode MTime Size
  </LocationMatch>
</IfModule>