ジャンゴModelAdminのGET_OBJECT最適化

Question

私はDjango ModelAdminリストビューでget_querysetを最適化しました：これらの最適化は、私はget_object変更ビューのために必要であることと同じではありません

• .only('field1', 'field2',)
• .select_related('rel1',)

：

• .only('field1', 'field2', 'field3',)
• .select_related('rel1__rel2', 'rel3',)
• .prefetch_related(...)

シングは、get_queryset and get_object are coupledです：

class BaseModelAdmin(...): 

    ... 

    def get_object(self, request, object_id, from_field=None): 
     """ 
     Returns an instance matching the field and value provided, the primary 
     key is used if no field is provided. Returns ``None`` if no match is 
     found or the object_id fails validation. 
     """ 
     queryset = self.get_queryset(request) 
     model = queryset.model 
     field = model._meta.pk if from_field is None else model._meta.get_field(from_field) 
     try: 
      object_id = field.to_python(object_id) 
      return queryset.get(**{field.name: object_id}) 
     except (model.DoesNotExist, ValidationError, ValueError): 
      return None 

どのように私は/上記のすべてのボイラープレートをコピー＆ペーストすることなく、get_querysetを上書きすることができますか？

Answer 1

：

def get_queryset(self, request): 
    queryset = super().get_queryset(request) 
    if request.resolver_match.url_name.endswith('_change'): 
     # admin change view 
     queryset = queryset.only(
      'iso_code', 
      *get_translation_fields('name'), 
      'official_languages', 
      'active', 
      'currency_code', 
      'currency_symbol', 
     ) 
    else: 
     # admin change list 
     queryset = queryset.only(
      'iso_code', 
      'name', 
      'active', 
     ) 
    return queryset 

Answer 2

あなたのユースケースはあまり一般的ではないので、get_objectを書き直すことなく、必要なものを達成するための賢明な方法はないと思います。私は良い妥協点を思わこの溶液で作ってみた

# A parameter with default False value shouldn't screw things up 
def get_queryset(request, for_object=False): 
    qs = super(YourModelAdmin, self).get_queryset(request) 
    if for_object: 
     qs = qs.select_related('rel1__rel2', 'rel3') 
     qs = .prefetch_related('rel4', 'rel5') 
     return qs.only('field1', 'field2', 'field3') 
    else: 
     qs = qs.select_related('rel1') 
     return qs.only('field1', 'field2') 

def get_object(self, request, object_id, from_field=None): 
    # Don't forget to add new param here 
    queryset = self.get_queryset_for_object(request, for_object=True) 
    model = queryset.model 
    field = model._meta.pk if from_field is None else model._meta.get_field(from_field) 
    try: 
     object_id = field.to_python(object_id) 
     return queryset.get(**{field.name: object_id}) 
    except (model.DoesNotExist, ValidationError, ValueError): 
     return None