[Tilecache] Adapting TileCache as a Java servlet

[Jon Blower]

Hi all,

For reasons that I went through in a previous post on the OpenLayers
mailing list (I think Christopher copied this list too), I'm looking
to integrate TileCache with my ncWMS software so that I can cache
tiles of data arrays (rather than images), allowing the same tiles to
be rendered in different ways.

To this end, I have converted TileCache to work as a Java servlet,
through the magic of Jython.  This seems to be working fine, but it
has raised a few questions:

1) Will TileCache cache images correctly for WMSs that support the
TIME and ELEVATION dimensions (and indeed, other arbitrary
dimensions)?

2) Is there any automatic management of the cache (e.g. deletion of
old tiles to prevent the cache getting too large) or is this something
I'd have to code myself?

3) For information: Jython 2.2b1 (the latest version) does not
implement the os.access function.  Therefore I had to make relatively
minor edits to Cache.py to simulate this function using the
java.io.File class.  My modified Cache.py should work in both Python
and Jython (I can post it if that would be helpful).

Other than point (3) above, the TileCache code seems to work fine in
Jython, but I've only done very limited testing.  Is anyone interested
in trying my Java version out?  It would be useful to know if it works
for others too.  For those of you who know about these things, I've
produced a WAR (web archive) file that should just drop into your
Tomcat/Jetty/whatever web application server.

Cheers, Jon

-- 
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Dr Jon Blower              Tel: +44 118 378 5213 (direct line)
Technical Director         Tel: +44 118 378 8741 (ESSC)
Reading e-Science Centre   Fax: +44 118 378 6413
ESSC                       Email: jdb at mail.nerc-essc.ac.uk
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