[Mapserver-users] Changing inline features with CGI parameters

[Jan Hartmann]

Hi Steve and list,

I'm trying to use a feature object for error messages. My mapfile looks 
like this:

map

layer
   ..
end

layer
   ..
end

layer
   transform false
   feature
     text "No data for this map
     points 10 10 end
   end
   class
      color  255 0 0
      ...
    end
end

Layers ar selected with expressions from the URL, and if no data are 
found, every layer but the last is turned off and the error message is 
displayed. Works fine. However, I want to be able to change the 
feature's text and position from the URL. The CGI Reference shows how to 
do this by creating a new feature from the URL:

...&map_webuser_feature=new&map_webuser_feature_points=12345.6789+12345.6789&map_webuser_feature_text=My+House!&..

This only works when *no* feature is defined in the MapFile, else 
nothing is shown. When omitting "feature=new" MapServer segfaults.

AFAICS existing features are not accessible from the URL. Is this by 
design, or can something be done about it? I am thinking of an 
application with lots of default error messages that can be toggled on 
and off individually in different positions. It would be easier to do 
this with predefined (and named) feature objects. I can live with the 
present situation though.

Jan