Blog Followup Links

I added a new feature to my blog: automatic generation of links to followup posts. For example, after writing Put it in the Syntax, I made a couple followup posts that elaborated on the ideas in that post. All of the followups link back to the original, but until now, if I wanted the original to link to the followups I had to put the links in by hand.

With a judicious mixture of server-side includes, a perl script, and crontab, I now have things set up so that every night my website will automatically put a followup link into any old post that I link to from a new post. Here's how it works.

This perl script gets run every night at midnight (via crontab). The script scans through the web page for each of my blog entries, and makes a list of the other entries that it links to. It then generates a new file for each entry, which contains a snippet of html listing all the followups to that post. If there are no followups, then the html snippet is empty. Next, I include the html snippet into the original page, by adding this line to my movabletype entry template:

<!--#include file="<$MTEntryId pad="1"$>.backlinks"-->

And voila, I have automatic generation of followup links. Check out the Put it in the Syntax post to see what it looks like (it's at the bottom of the post, just before the comments). Note that this post isn't actually listed as a followup, because I linked to that post using a different url syntax than I normally do, so it isn't picked up by the perl script.