Compress http responses

[twagoo]

Follow up of #28: compress http responses to reduce response time. This can be achieved through the Tomcat configuration, as described in this article as well as the official documentation.

Example server.xml snippet (from the article, not tailored for the VLO!):

<Connector compressableMimeType="text/html,text/xml,text/css,text/javascript, application/x-javascript,application/javascript"
compression="on"
compressionMinSize="128"
connectionTimeout="20000"
noCompressionUserAgents="gozilla, traviata"
port="8080"
redirectPort="8443" protocol="HTTP/1.1" />

The admin(s) should check wether this works as intended with the Apache and/or nginx proxies.

See Component Registry #15 for a similar proposal.

[twagoo]

I have been successful on alpha-vlo.clarin.eu (Scientific Linux 7) with the following additions to httpd.conf:

LoadModule deflate_module modules/mod_deflate.so
LoadModule headers_module modules/mod_headers.so
LoadModule mime_module modules/mod_mime.so

###### gzip compression #########
<IfModule mod_mime.c>
 AddType application/x-javascript .js
 AddType text/css .css
</IfModule>
<IfModule mod_deflate.c>
 AddOutputFilterByType DEFLATE text/css application/x-javascript text/x-component text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/javascript
 <IfModule mod_setenvif.c>
  BrowserMatch ^Mozilla/4 gzip-only-text/html
  BrowserMatch ^Mozilla/4\.0[678] no-gzip
  BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
 </IfModule>
 <IfModule mod_headers.c>
  Header append Vary User-Agent env=!dont-vary
 </IfModule>
</IfModule>

This approach should also work on vlo.clarin.eu (CentOS).

On beta, which uses nginx, it should be as easy as following this guide. Make sure to use the same list of mime types:

text/css application/x-javascript text/x-component text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/javascript

and that CSS and JS files are matched with the right mime type.

[twagoo]

For docker compose based deployment scenarios, nginx proxy handles this. See https://gitlab.com/CLARIN-ERIC/compose_vlo/issues/7