[mapserver-users] MapCache: returning blank tiles when outside restricted extents?

[John Taranu]

We're having some problems with MapCache with a fully-seeded cache covering
a small geographic extent.  

If the tileset definition doesn't have a restricted_extent, then any
requests outside the cache extents are supposed to return blank tiles, and
those blank tiles are being saved to the cache directory structure as
symlinks.  I want to avoid that, for two reasons:
   1. There will be lots of requests outside the cache extent, and I want to
avoid creating hundreds of thousands of symlinks (and empty directories)
   2. The cache was originally seeded as user "root", but the MapCache web
service runs as another user (either "apache" or the nginx user), and that
user cannot write to the cache directory.  

If instead I set the grid (inside the tileset definition) to have a
restricted_extent,  then any requests outside the cache extents throw an
error.  

Is there some way force MapCache to return a blank tile for requests outside
the restricted_extent, without saving that tile into the cache?

---------------------------------------
John Taranu
Senior Web Developer
First Base Solutions Inc
email: jtaranu at firstbasesolutions.com
web: firstbasesolutions.com