apt-xapian-index has just been approved into experimental, and in the next days I'm going to blog more about it.
The package contains a tool called update-apt-xapian-index that indexes
Debian package metadata into a Xapian index located
The index is read-only, except for
however, it is world-readable: every user can query it, all the time, at the
same time, even during index updates.
The index can contain more than package descriptions.
update-apt-xapian-index indexes data using plugins located in
/usr/share/apt-xapian-index/plugins, and any package can add their own. For
example, debtags will provide a plugin to
Since Xapian can index numeric values as well, if anyone makes a popcon package that downloads popcon information, they can provide a plugin to index popcon values. If anyone makes an iterating package that downloads ratings, they can provide a plugin to index ratings.
Another plugin could be a specialised Debian stemmer that generates token such as foo out of libfoo-dev.
I think you get the idea: it's very extensible. You can have a look at the initial set of plugins in subversion.
The index is also self-documenting, so that one can keep track of all the
intresting things that can be found in it.
update-apt-xapian-index does not
only maintain the index, but also the file
that aggregates documentation provided by the plugins.
To query the index, you just use Xapian. Debian contains Xapian bindings for various languages:
- libxapian-dev for C++
- libsearch-xapian-perl for Perl
- libxapian-ruby1.8 for Ruby
- python-xapian for Python
- tclxapian for Tcl
- php5-xapian for PHP
In the next days I am going to post various example queries and interesting tricks that the index allows you to do.
It's going to be fun.
Next in the series: performing a simple query.