new_idea.py

class QueryParamReader:
    class Meta:
        model = Event
        grouping_params = [
            "day",
            "device_type",
            "category",
            "client",
            "client_group",
            "valid",
        ]
        ordering_params = utils.ascify_descify(sorting_fields)
        filtering_params = grouping_fields
        query_delimiter = " "


#####################################################################


class QueryParamReader:
    class Meta:
        model = Event
        query_delimiter = " "

    group_by = GroupingParam(
        restrict_to=[
            "day",
            "device_type",
            "category",
            "client",
            "client_group",
            "valid",
        ]
    )
    order_by = OrderingParam(
        restrict_to=utils.ascify_descify(
            ["day", "device_type", "category", "client", "client_group", "valid"]
        )
    )
    # the filtering param class
    # deduces the type of the param value from the field on the model
    # and may take a list of allowed values (restrict_to) for the param
    # you may also specify whether it is to accept only one (singular) value
    # or appropriately delimited multiple values
    # it accepts multiple values by default
    clients = FilteringParam("client")
    client_groups = FilteringParam("client_group")
    device_types = FilteringParam("device_type", restrict_to=Event.DEVICE_TYPE_CHOICES)
    categories = FilteringParam("category")
    valid = FilteringParam("valid", singular=True)
    # would have to write a 'date' transform for the following to work
    start_date = FilteringParam("timestamp", singular=True, filter_op="date__gte")
    end_date = FilteringParam("timestamp", singular=True, filter_op="date__lte")

    def __init__(self, *args, **kwargs):
        # prepare all params
        # ensure the same thing isn't specified in meta and outside meta
        # ensure params are in line with existing fields on specified model
        pass

    def read(self, request, queryset, *args, **kwargs):
        # read the query params
        # return an appropriately modified queryset
        # ex.
        #   return (queryset
        #       .filter(
        #           Q(valid=True),
        #           Q(timestamp__date__gte=2018-09-04),
        #           Q(category=864) | Q(category=141) | Q(category=308)
        #       )
        #       .values('client', 'category', 'device_type')
        #       .order_by('client', '-device_type')
        #   )
        pass

    def full_clean(self, params_dict, *args, **kwargs):
        # params_dict is a map of all read parameters and their values
        # this is where you can do things like
        # making sure the values of one parameter are a subset of
        # the values of some other parameter
        # you can even modify parameter values here
        # make sure to return the resulting params_dict
        return params_dict


class Param:
    pass

class FilteringParam(Param):
    pass

class GroupingParam(Param):
    pass

class OrderingParam(Param):
    pass