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This page is part of the [wiki:Future MapGuide Future] section, where ideas are proposed and refined 
before being turned into RFCs (or discarded).  Visit the [wiki:Future] page to view more!

= Overview =

This page is a living proposal for improving the scalability of the Tile Service. [[BR]]
Mapguide supports tiled maps via both WMS and it's own Tile Service using GETTILETIMAGE.

Recently support was added in Openlayers & Fusion to access the Tile Service via an API.[[BR]]
[http://dev.openlayers.org/apidocs/files/OpenLayers/Layer/MapGuide-js.html OpenLayers. Layer. MapGuide][[BR]]
[http://trac.openlayers.org/ticket/995 #995 (add support for MapGuide OS layer type) - OpenLayers - Trac][[BR]]


= API Ideas =

'''SETTILEIMAGE''' would allow the tile cache to seeded without needing to have remote access to the server file system.

'''GETTILEPARAMS''' would return a list of scale ranges, tile sizes and bounds for a given tile cache.

'''GETTILECACHE''' would return a 'map' of the tile cache, listing which tiles exist and which ones haven't yet been created

'''HAVETILEIMAGE''' would enable a server to poll another server(s) in the cluster, [[BR]]
returning status codes of 200 ok or 404 Not Found respectively. This allows the server to[[BR]]
check the tile cache without triggering a tile render on the polled server.

These would enable more extensive API based management of a cluster of Mapguide servers, via accurate seeding[[BR]]
and management of the tile caches. 

= Cacheability Ideas =

[wiki:MapGuideRfc11] added support for a '''Stateless Http GETTILEIMAGE request''', however, these tiles are served [[BR]]
without any cache headers which means they can only be proxied using a custom 'aggressive' proxy service. [[BR]]

[ticket:467 Add proper cache headers & file date to GETTILEIMAGE response] addresses this issue. 

Some of the issues to be resolved is how long to set the cache headers to cache the tiles before checking back [[BR]]
to the Mapguide Server. This could done with a serverconfig.ini default and then an overriding parameter in the [[BR]]
ResourceHeader.

= WMS =

[ticket:286: WMS Cache headers] - see above.

[ticket:285: Publish MapDefinitions via WMS] Currently only layers are exposed via WMS, maps should be as well.  

The WMS service doesn't currently use the tile cache, which means every WMS request is rendered. [[BR]]

Linking the WMS service up to utilize the tile cache would dramatically improve the performance [[BR]]
and capacity of WMS with Mapguide.[[BR]]