[Mapserver-users] WMS server - client communication error

Daniel Morissette dmorissette at dmsolutions.ca
Fri May 7 12:53:01 EDT 2004

Sean Gillies wrote:
> The Python mapscript module is set up so that the MapServer error stack is
> checked after method calls (such as mapObj.draw), MapServer errors are
> converted to Python exceptions and are raised.
> Somewhere in msDrawMap, maybe in the WMS HTTP request code, 
> msLookupHashTable
> is being used to access layer or map metadata and is not finding something
> it expects.  Maybe your mapfile lacks a WMS metadata parameter?
> In the CGI MapServer, such an error will be reported but will
> not necessarily stop execution of the program.  With the Python MapScript,
> unhandled exceptions will stop execution.

Ah... makes sense now. If you add a dummy METADATA block to your layer 
definition then the error should go away. (I've been able to reproduce 
here in the debugger.)

I have created bug 650 to discuss the solution to this problem:

I'll make sure the fix makes it in v4.2

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

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