Enable use of @property's and callables in fields

[bernardotorres]

Hi @noirbizarre and folks. This has also been a issue with me. I wanted to display data defined as @property and also transform the data to present it in a more pleasant way, with widgets, for example (in my specific case, I had a Batch object with a printProgress @property which I wanted to present as a progress bar.

So I made a patch.

This was the final result:

This is how the DataTable was defined:

class BatchDatatablesView(DatatablesView):
    model = Batch
    fields = {
        'client':'client__name',
        'start':'start',
        'quantity':'quantity',
        'credential':'credential',
        'progress':showProgress,
    }

credential is a @property of Batch.

showProgress is a callable which takes the row (Django ORM single object) and returns a string to be displayed. In this case:

def showProgress(row):
    return """<div class="progressbar_outer">
<div class="progressbar_percentage" style="width: %d%%" />
</div>""" % row.printProgress

The present patch does not enable searching from properties or callables, but I don't think it would be a good idea anyway.

I'm opening a pull-request.

[coveralls]

Coverage decreased (-0.84%) when pulling fdf1e86 on bernardotorres:master into 347e74d on noirbizarre:master.