[pygeoapi] Process - how to return a reference?

[Francesco Martinelli]

Hi there,
I am new to this list, and possibly I am asking simple questions,
but I found no info around in the web.

I would like to publish a "process",
and to allow for the result(s) to be returned as reference.
I installed and tested pygeoapi,
but I didn't find an example/template to request the result as reference,
i.e. using the parameter "transmissionMode": "reference".

The case I am interested in, is where the output parameter to return as 
reference is a file (i.e. a generic bytestream).
However I also wonder if a process with
"outputTransmission": ['value', 'reference']
should also allow for all other output parameter types to be retrieved 
as reference.
Also, having "outputTransmission": ['reference'] (i.e. without the 
option 'value') would conform to the standard?


What I am looking for is:
a basic example on the response (including the headers) that the client 
is expected to receive where an output parameter of an execute request 
has set the property "transmissionMode": "reference".
Even better if it were possible to have a code snippet on how to make it.

Also, in api.py, describe_processes(), I found the "outputTransmission" 
is fixed to only be ['value'],
while there is no option to load the process metadata specific value 
associated to "outputTransmission".

I would like to minimize (if not avoiding) the changes in pygeoapi 
framework, while allowing this option.


Thank you for any help,
Francesco