212 lines
7.7 KiB
Python
212 lines
7.7 KiB
Python
"""
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Basic building blocks for generic class based views.
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We don't bind behaviour to http method handlers yet,
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which allows mixin classes to be composed in interesting ways.
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"""
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from rest_framework import status
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from rest_framework.response import Response
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from rest_framework.settings import api_settings
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from rest_framework import mixins
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from libraries.cache_mixins import CacheGetMixin, CacheSetMixin, CacheDeleteMixin
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# Mixin classes to be included in the generic classes
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class CachedCreateModelMixin(CacheDeleteMixin, mixins.CreateModelMixin):
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"""
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A slightly modified version of rest_framework.mixins.CreateModelMixin that handles cache deletions.
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"""
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def create(self, request, *args, **kwargs):
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# Go on with the creation as normal
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serializer = self.get_serializer(data=request.data)
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serializer.is_valid(raise_exception=True)
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self.perform_create(serializer)
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headers = self.get_success_headers(serializer.data)
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# Delete the cache
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self.delete_cache(request)
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return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
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class CachedRetrieveModelMixin(CacheGetMixin, CacheSetMixin):
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"""
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A slightly modified version of rest_framework.mixins.RetrieveModelMixin that handles cache attempts.
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mixins.RetrieveModelMixin only has the retrieve method so it doesn't stand to inherit anything from it.
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"""
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def retrieve(self, request, *args, **kwargs):
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# Attempt to get the request from the cache
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cache_attempt = self.get_cache(request)
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if cache_attempt:
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return Response(cache_attempt)
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else:
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# The cache get attempt failed so we have to get the results from the database
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instance = self.get_object()
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serializer = self.get_serializer(instance)
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response = Response(serializer.data)
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self.set_cache(request, response)
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return response
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class CachedUpdateModelMixin(CacheDeleteMixin, mixins.UpdateModelMixin):
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"""
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A slightly modified version of rest_framework.mixins.UpdateModelMixin that handles cache deletes.
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"""
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def update(self, request, *args, **kwargs):
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partial = kwargs.pop('partial', False)
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instance = self.get_object()
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serializer = self.get_serializer(instance, data=request.data, partial=partial)
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serializer.is_valid(raise_exception=True)
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self.perform_update(serializer)
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if getattr(instance, '_prefetched_objects_cache', None):
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# If 'prefetch_related' has been applied to a queryset, we need to
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# forcibly invalidate the prefetch cache on the instance.
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instance._prefetched_objects_cache = {}
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# Delete the related caches
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self.delete_cache(request)
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return Response(serializer.data)
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class CachedDestroyModelMixin(CacheDeleteMixin, mixins.DestroyModelMixin):
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"""
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A slightly modified version of rest_framework.mixins.DestroyModelMixin that handles cache deletes.
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"""
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def destroy(self, request, *args, **kwargs):
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instance = self.get_object()
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self.perform_destroy(instance)
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# Delete the related caches
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self.delete_cache(request)
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return Response(status=status.HTTP_204_NO_CONTENT)
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# List mixin classes to be included with list generic classes
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class CachedListCreateModelMixin(CacheDeleteMixin):
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"""
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A fully custom mixin that handles mutiple instance cration.
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"""
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def list_create(self, request, *args, **kwargs):
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# Go on with the creation as normal
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serializer = self.get_serializer(data=request.data, many=True)
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serializer.is_valid(raise_exception=True)
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self.perform_create(serializer)
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headers = self.get_success_headers(serializer.data)
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# Delete the cache
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self.delete_cache(request)
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return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
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def perform_create(self, serializer):
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serializer.save()
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def get_success_headers(self, data):
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try:
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return {'Location': str(data[api_settings.URL_FIELD_NAME])}
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except (TypeError, KeyError):
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return {}
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class CachedListRetrieveModelMixin(CacheGetMixin, CacheSetMixin):
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"""
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A slightly modified version of rest_framework.mixins.ListModelMixin that handles cache saves.
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mixins.ListModelMixin only has the list method so it doesn't stand to inherit anything from it.
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"""
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def list(self, request, *args, **kwargs):
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# Attempt to get the request from the cache
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cache_attempt = self.get_cache(request)
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if cache_attempt:
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return Response(cache_attempt)
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else:
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# The cache get attempt failed so we have to get the results from the database
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queryset = self.filter_queryset(self.get_queryset())
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if self.paged:
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page = self.paginate_queryset(queryset)
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if page is not None:
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serializer = self.get_serializer(page, many=True)
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response = self.get_paginated_response(serializer.data)
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else:
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serializer = self.get_serializer(queryset, many=True)
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response = Response(serializer.data)
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else:
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serializer = self.get_serializer(queryset, many=True)
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response = Response(serializer.data)
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self.set_cache(request, response)
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return response
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class CachedListUpdateModelMixin(CacheDeleteMixin):
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"""
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A fully custom mixin that handles mutiple instance updates.
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"""
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def list_update(self, request, *args, **kwargs):
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partial = kwargs.pop('partial', False)
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queryset = self.filter_queryset(self.get_queryset())
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serializer = self.get_serializer(queryset, data=request.data, partial=partial, many=True)
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serializer.is_valid(raise_exception=True)
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self.perform_update(serializer)
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# Delete the related caches
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self.delete_cache(request)
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return Response(serializer.data)
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def perform_update(self, serializer):
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serializer.save()
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def list_partial_update(self, request, *args, **kwargs):
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kwargs['partial'] = True
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return self.list_update(request, *args, **kwargs)
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class CachedListDestroyModelMixin(CacheDeleteMixin):
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"""
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A fully custom mixin that handles mutiple instance deletions.
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"""
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def list_destroy(self, request, *args, **kwargs):
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# Go on with the validation as normal
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serializer = self.get_serializer(data=request.data, many=True)
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serializer.is_valid(raise_exception=True)
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validated_data = serializer.validated_data
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# TODO does this new stuff work even? need to check on the frontend
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serializer.delete(validated_data)
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# for instance in self.get_objects():
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# if instance is not None:
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# self.perform_destroy(instance)
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# Delete the related caches
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self.delete_cache(request)
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return Response(status=status.HTTP_204_NO_CONTENT)
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#def perform_destroy(self, instance):
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# instance.delete()
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#def get_objects(self):
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# """
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# The custom list version of get_object that retrieves one instance from the #database. It yields model instances with each call.
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# """
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# queryset = self.filter_queryset(self.get_queryset())
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#
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# if len(queryset):
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# for obj in queryset.all():
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# # May raise a permission denied
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# self.check_object_permissions(self.request, obj)
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# yield obj
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#yield None
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