This is versioncheck 1.0, a first stab at automatic checking of versions of

Python extension packages installed on your system.

The basic idea is that each package contains a _checkversion.py

somewhere, probably at the root level of the package. In addition, each

package maintainer makes a file available on the net, through ftp or

http, which contains the version number of the most recent distribution

and some readable text explaining the differences with previous

versions, where to download the package, etc.

The checkversions.py script walks through the installed Python tree (or

through a tree of choice), and runs each _checkversion.py script. These

scripts retrieve the current-version file over the net, compares version

numbers and tells the user about new versions of packages available.

A boilerplate for the _checkversion.py file can be found here. Replace

package name, version and the URL of the version-check file and put it in

your distribution. In stead of a single URL you can also specify a list

of URLs. Each of these will be checked in order until one is available,

this is handy for distributions that live in multiple places. Put the

primary distribution site (the most up-to-date site) before others.

The script is executed with execfile(), not imported, and the current

directory is the checkversion directory, so be careful with globals,

importing, etc.

The version-check file consists of an rfc822-style header followed by

plaintext. The only header field checked currently is

'Current-Version:', which should contain te current version and is

matched against the string contained in the _checkversion.py script.

The rest of the file is human-readable text and presented to the user if

there is a version mismatch. It should contain at the very least a URL

of either the current distribution or a webpage describing it.

Pycheckversion.py is the module that does the actual checking of versions.

It should be fine where it is, it is imported by checkversion before anything

else is done, but if imports fail you may want to move it to somewhere

along sys.path.

	Jack Jansen, CWI, 23-Dec-97.

	<jack@cwi.nl>