MapServer 5.0 WMS, requiring styles...
Daniel Morissette
dmorissette at MAPGEARS.COM
Tue Oct 16 13:59:39 EDT 2007
Frank Warmerdam wrote:
>
> Following up on this, the RFC is at:
>
> http://mapserver.gis.umn.edu/development/rfc/ms-rfc-35
>
> I would appreciate comment for a day or two and then I will call for a
> vote.
>
I understand the STYLES issue is real and needs to be addressed, but I
don't like where this is going.
The RFC is encouraging developers and users to add a bunch of permissive
exceptions in 5.1 and future releases that may not really be needed to
achieve interoperability. This would just result in bloating the code
and making it more complex and harder to test. BBOX and SIZE may have
some defaults in the mapfile, but a GetMap request without them makes
little sense so I would be against making them optional again (even if I
used to use GetMap without them a lot myself when testing mapfiles in
the past). OTOH, the STYLES option has a logical default stated in the
spec (STYLES=<empty>) and I think we all agree that it would have made
sense for STYLES to be optional in the spec in the first place.
I'd be more in favor of calling the options "pedantic" (with its
negative connotation) and "permissive", with permissive being the
default, and for the time being stating in the RFC that STYLES is the
only parameter that changes behavior in permissive mode... and that
adding more exceptions in the permissive mode should not be taken
lightly as this encourages misuse of the specs and bloats the code with
unnecessary exceptions.
With respect to scanning the WARNINGS in capabilities. At least in the
case of WMS, MapServer should already be producing suitable defaults in
addition to the warnings (making the response compliant anyway). If it
is not possible to produce a suitable default then an exception is
already issued, so there should be nothing to do on that front, unless
WFS or WCS were implemented differently.
Finally, in case anyone is worried about that, making STYLES optional
will not prevent us from getting compliance certification since the CITE
tests do not check whether a server enforces the requirement for the
STYLES parameter. That could be why so many servers out there never
implemented the requirement for STYLES and so many clients were able to
get away without it.
Daniel
--
Daniel Morissette
http://www.mapgears.com/
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