[OSM-dev] White satellite tiles cached

[Mikel Maron]

Oh that's not pretty. The landsat tile cache has stored bad responses from OnEarth. These responses had a valid HTTP response code, so we're cached incorrectly.

The mime-type on these stored tiles is application/vnd.ogc.se_xml. This is the mime type returned by a WMS Service Exception. (why couldn't they just use HTTP headers in the WMS spec, grumble...)

So the fix is two steps

- Add access controls to the squid config to only cache image mime-types. No problem with http://wiki.squid-cache.org/config/http_reply_access 

- Remove all the bad tiles from the cache. I haven't found any prebuilt utilities to purge by mime-type or size, so I'll need to script something custom.

Lots on my plate this moment, will get to this asap. Or if anyone wants to dig into squid and cook up the acl config and a purge by mime-type script, that would be very cool.

Mikel


----- Original Message ----
From: Lars Aronsson <lars at aronsson.se>
To: dev at openstreetmap.org
Sent: Tuesday, February 21, 2006 8:19:10 AM
Subject: [OSM-dev] White satellite tiles cached


There are white satellite tiles cached here,
http://www.openstreetmap.org/index.html?lat=57.70&lon=11.94&zoom=9
and in some other places.

There seems to be no way a user can purge this cache.

A typical white tile in JPEG format is 1200 bytes and has the 
md5sum 68204e77d4484642f12e36dd9f3e2774



-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se

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