[mapserver-users] cascading mapserver

[Daniel Morissette]

Bart van den Eijnden wrote:
> 
> How does it work with vendor specific parameters? I want to use mapserver
> to be a cascading mapserver for 2 mapservers of a different brand. But
> those guys have made vendor specific parameters like query_layers and
> query_params to get a selection highlighted in the map.
> 
> Will mapserver send those vendor specific parameters (although not OpenGIS
> WMS parameters) to the mapserver of the different brand?
> 

If you include vendor-specific parameters in the CONNECTION URL in your
layer definition then MapServer will just forward those parameter and
ignore them.  In other words, the CONNECTION URL in a WMS layer
definitino is an opaque string and MapServer doesn't try to parse it or
validate the parameters in it.  Well, there is one exception: it checks
the VERSION parameter in the CONNECTION url to makes sure that it builds
its parameters properly, but it doesn't change any of the
vendor-specific parameters.

FYI QUERY_LAYERS is not vendor-specific: it's part of the spec.  OTOH,
QUERY_PARAMS would be considered vendor-specific.  So hopefully this WMS
doesn not complain if you include a QUERY_PARAMS value in a GetMap
request, if it doesn't complain then just include your QUERY_PARAMS
value in the CONNECTION url in your mapfile and you should be fine.

Daniel
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 Daniel Morissette               morissette at dmsolutions.ca
 DM Solutions Group              http://www.dmsolutions.ca/
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