RSS feed disk-based caching

I think supercache used to disk-cache RSS feeds, but that stopped working somewhere in the last 5 years ago or so, and I saw a message from Donncha a while ago that it isn’t supposed to work any more, but just uses the legacy wp-cache.

I have a site whose RSS feeds are the most popular part of the site, and so caching those greatly improves performance, so I worked on getting it to work tonight.

Here’s how I did it:

Modifications to .htaccess:

# special case for RSS feeds
RewriteCond %{HTTP:Cookie} !^.*(wordpress_logged_in|wp-postpass_).*$
RewriteCond %{DOCUMENT_ROOT}/wp-content/cache/supercache/%{SERVER_NAME}/$1/feed.xml -f
RewriteRule ^(.*) "/wp-content/cache/supercache/%{SERVER_NAME}/$1/feed.xml" [L]
</IfModule>

(I left the logged_in and postpass part there – the postpass probably doesn’t make any sense, but I thought logged in people might like to see the most recent version, and this site doesn’t have lots of logins, other than the administrators).

Then, I made a shell script:

#!/bin/bash

# delete and recreate supercache feeds

SITE="http://www.example.com/"

SUPERCACHE_DIR="/home/example/wp-content/cache/supercache/www.example.com/"

FEEDS="feed/ feed/podcast/"

INDEX_FILE="feed.xml"

############### STOP EDITS #############

TEMP_FILE=<code>mktemp</code>

for feed in $FEEDS; do
        file="${SUPERCACHE_DIR}${feed}${INDEX_FILE}"
        rm $file &> /dev/null
        wget -qO $TEMP_FILE $SITE$feed
        if [ $? == 0 ] ; then
                chmod a+r $TEMP_FILE
                mv $TEMP_FILE $file
        fi
done

And then added a cronjob to run this script every 15 minutes:
*/15 * * * * /home/example/bin/generate_feeds.sh

I originally had some mime-type stuff in an .htaccess file to set ForceType to text/xml, but I removed it because the apache server was already doing the right thing without that.

Tada. Server load dropped by 60%!

https://ww.wp.xz.cn/plugins/wp-super-cache/