[Qgis-developer] [QGIS-Processing] Define optional parameters in Script

[Victor Olaya]

Aside from the syntax...I am not sure it is a good idea...

I mean, it is a good idea to allow optional parameters...but that is a
big change in the current semantics of Processing algorithms. Some
params can be optional (layers, tables), and have a setting for that.
When they are not used, their value is None, but the value has to be
passed (so an optional layer param is a layer param that can be None).
Allowing optional parameters would require some importante changes in
many places in Processing, specially in the modeler, so i would
suggest some more discussion about this.

Not sure if that can maybe be added to the WPS plugin part, so nothing
changes in Processing, but the WPS service exposes the parameters as
optional and then fills the values with a default one before actually
callin gprocessing.

Hope this helps

2015-09-11 11:28 GMT+02:00 kimaidou <kimaidou at gmail.com>:
> Hi
>
> I would personaly use the second : add a new property for each input. If not
> given, this means the input is mandatory, if "opt" is present, make it
> optionnal.
>
> Cheers,
> Michael
>
> 2015-08-28 14:53 GMT+02:00 René-Luc Dhont <rldhont at gmail.com>:
>>
>> Hi Victor,
>>
>> I'm working on porting QGIS Processing to Web Processing Service, and I
>> have found that all parameters in a QGIS Processing script are mandatory.
>> It would be useful to power define some parameters as optional.
>>
>> I think that I can propose some code but I'd like to know what is your
>> preferred way of defining optional parameters :
>> * an header line started by 'optional' with a list of parameter name
>> separated by comma
>> ##optional=SEGMENTS,DISTANCE
>> * an extra value at the end of the header line
>> ##SEGMENTS=number 5 opt
>>
>> Thanks
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>
>
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