WPSRequest.json() better error handling

[idanmiara]

Overview

pywps/app/WPSRequest.py - gaurd WPSRequest.json() with try...except to better handle some inputs. especially inputs with "complex" extra fields, which otherwise would raise 500 error. If someone wants to pass a complex input parameter:

    "extent": {
        "type": "bbox",
        "bbox": [32, 34.7, 32.1, 34.8]
    }

As there are no remarks in JSON, I normally add an underscore to the parameter name if I want it to be ignored. if "_extent" is not a parameter for the request then without this fix error 500 would be returned.

Related Issue / Discussion

Additional Information

Contribution Agreement

(as per https://github.com/geopython/pywps/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• [X] I'd like to contribute [feature X|bugfix Y|docs|something else] to PyWPS. I confirm that my contributions to PyWPS will be compatible with the PyWPS license guidelines at the time of contribution.
• [X] I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[coveralls]

Coverage remained the same at 0.0% when pulling f09f4699136a330a00946dfbb3bc85a4c08639c7 on talos-gis:error_handling2 into 77aa30a2d5e72868099308301a3e1dbfd8fbcedc on geopython:main.