NEILB's Blog

BARBIE and I have been working on a new BackPAN index, and some related things. At the centre of this are BackPAN::Index::Create and create-backpan-index, the module and associated script that can be used to create a BackPAN index. This is now the index used by CPAN::ReleaseHistory, so it's relying on an open-source BackPAN index.

CPAN / BackPAN indexes were one of the potential topics for the QA Hackathon this year, and one of the potential projects was an open source "BackPAN index". We didn't get to it at the hackathon, but it's been in my mental backlog since then.

A few weeks after that, BARBIE asked me why my CPAN release tracker pages (once a month / week / day, and NeoCPANisms) weren't updating very often. It was because they were built on my CPAN::ReleaseHistory module, which at that point used an existing BackPAN index. The index wasn't updated very often, and I didn't know who looked after it.

A little while after that there was one day when various of my scripts didn't update, because CPAN::ReleaseHistory couldn't get the BackPAN index. I realised that I was depending on something that I knew very little about, and had no control over.

This led to the following sequence of events:

• I created BackPAN::Index::Create, and suggested that maybe BARBIE could use it to generate indexes for the CPAN Testers BackPAN. We've iterated on this for the last 6 weeks or so.
• BARBIE and I iterated on the text for his BackPAN home page.
• Barbie wrote a script to generate different permutations of indexes; these are listed on the BackPAN home page. This script is now in the examples directory of the BackPAN-Index-Create distribution.
• I updated CPAN::ReleaseHistory to use the new index; the design of the new index greatly simplified this module.
• Doing this prompted some changes in MooX::Role::CachedURL, so it could be used by CPAN::ReleaseHistory.

I've realised that perhaps the module should have been called CPAN::Index::Create — with some additional options it could be used to generate a 'latest releases' index, as an alternative backend for CPAN::Releases::Latest, which currently has just one backend, for MetaCPAN.

This is still very much a 'beta release' of the indexes, so Barbie and I are happy to hear suggestions for improvements.