62 lines
1.6 KiB
Python
62 lines
1.6 KiB
Python
import json
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from typing import TypeAlias, TypedDict, TypeVar
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from django.db.models import Model, Q
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from django.db.models.query import QuerySet
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filter_types = {
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"session_start": {
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"equals": "timestamp_start__year__exact=",
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"isnull": "timestamp_start__exact=None",
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"greater_than": "timestamp_start__gt=",
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"less_than": "timestamp_start__lt=",
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},
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}
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class Filter(TypedDict):
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name: str
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operator: str
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value: str
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FilterList: TypeAlias = list[Filter]
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def string_to_django_filter_dict(s: str, value: str = "") -> dict[str, str | int]:
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if s[-1] == "=":
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s += value
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key, value = s.split("=")
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return {key: value}
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T = TypeVar("T", bound=Model)
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def apply_json_filter[T](s: str, queryset: QuerySet[T]) -> QuerySet[T]:
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filter_obj = urlsafe_json_decode(s)
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name, operator, value = (filter_obj[k] for k in ["name", "operator", "value"])
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if name in filter_types:
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if operator in filter_types[name]:
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filtered = queryset.filter(
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Q(**string_to_django_filter_dict(filter_types[name][operator], value))
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)
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return filtered
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return queryset
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urlsafe_encode_table = str.maketrans({",": "^", ":": "-", " ": ""})
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urlsafe_decode_table = str.maketrans({"^": ",", "-": ":"})
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def urlsafe_json_encode[T](obj: T) -> str:
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json_string = json.dumps(obj)
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safe_string = json_string.translate(urlsafe_encode_table)
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return safe_string
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def urlsafe_json_decode[T](s: str) -> T:
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unsafe_string = s.translate(urlsafe_decode_table)
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obj = json.loads(unsafe_string)
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return obj
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