Django的Tastypie先進的過濾：如何做複雜的查找符合Q對象

Question

我有一個基本的Django模型，如：

class Business(models.Model): 
    name = models.CharField(max_length=200, unique=True) 
    email = models.EmailField() 
    phone = models.CharField(max_length=40, blank=True, null=True) 
    description = models.TextField(max_length=500) 

我需要像上述模型執行復雜查詢：

qset = (
    Q(name__icontains=query) | 
    Q(description__icontains=query) | 
    Q(email__icontains=query) 
    ) 
results = Business.objects.filter(qset).distinct() 

我曾嘗試以下使用tastypie沒有運氣：

，並在課堂上爲元我tastypie已濾波設置爲：

filtering = { 
     'name: ALL, 
     'description': ALL, 
     'email': ALL, 
     'query': ['icontains',], 
    } 

任何想法我怎麼能解決呢？

感謝 - 牛頓

Answer 1

你是在正確的軌道上。但是，build_filters應該將資源查找轉換爲ORM查找。

默認實現將基於__的查詢關鍵字拆分爲key_bits，value對，然後嘗試查找查找到的資源與其ORM等效項之間的映射。

你的代碼不應該應用在那裏只有構建它的過濾器。下面是改進和修正版本：

def build_filters(self, filters=None): 
    if filters is None: 
     filters = {} 
    orm_filters = super(BusinessResource, self).build_filters(filters) 

    if('query' in filters): 
     query = filters['query'] 
     qset = (
       Q(name__icontains=query) | 
       Q(description__icontains=query) | 
       Q(email__icontains=query) 
       ) 
     orm_filters.update({'custom': qset}) 

    return orm_filters 

def apply_filters(self, request, applicable_filters): 
    if 'custom' in applicable_filters: 
     custom = applicable_filters.pop('custom') 
    else: 
     custom = None 

    semi_filtered = super(BusinessResource, self).apply_filters(request, applicable_filters) 

    return semi_filtered.filter(custom) if custom else semi_filtered 

因爲你是用品質的對象，標準apply_filters方法是不是足夠聰明，應用自定義過濾器鍵（因爲是沒有的），但是你可以迅速覆蓋它，添加一個稱爲「自定義」的特殊過濾器。這樣做你的build_filters可以找到一個合適的過濾器，構建它的意思，並將它作爲自定義傳遞給apply_filters，它將直接應用它，而不是試圖從字典中將它的值作爲一個項目解壓縮。

Answer 2

我解決這樣的問題，所以：

Class MyResource(ModelResource): 

    def __init__(self, *args, **kwargs): 
    super(MyResource, self).__init__(*args, **kwargs) 
    self.q_filters = [] 

    def build_filters(self, filters=None): 
    orm_filters = super(MyResource, self).build_filters(filters) 

    q_filter_needed_1 = [] 
    if "what_im_sending_from_client" in filters: 
     if filters["what_im_sending_from_client"] == "my-constraint": 
     q_filter_needed_1.append("something to filter") 

    if q_filter_needed_1: 
     a_new_q_object = Q() 
     for item in q_filter_needed: 
     a_new_q_object = a_new_q_object & Q(filtering_DB_field__icontains=item) 
     self.q_filters.append(a_new_q_object) 

    def apply_filters(self, request, applicable_filters): 
    filtered = super(MyResource, self).apply_filters(request, applicable_filters) 

    if self.q_filters: 
     for qf in self.q_filters: 
     filtered = filtered.filter(qf) 
     self.q_filters = [] 

    return filtered 

這種方法感覺比我見過別人的關注清晰分離。

Answer 3

在astevanovic的答案中提出了這個想法，並將其清理一下，以下內容應該可以工作，並且更加簡潔。

主要區別在於，使用None作爲關鍵字而不是custom（可能與列名衝突），使apply_filters更加健壯。

def build_filters(self, filters=None): 
    if filters is None: 
     filters = {} 
    orm_filters = super(BusinessResource, self).build_filters(filters) 

    if 'query' in filters: 
     query = filters['query'] 
     qset = (
       Q(name__icontains=query) | 
       Q(description__icontains=query) | 
       Q(email__icontains=query) 
       ) 
     orm_filters.update({None: qset}) # None is used as the key to specify that these are non-keyword filters 

    return orm_filters 

def apply_filters(self, request, applicable_filters): 
    return self.get_object_list(request).filter(*applicable_filters.pop(None, []), **applicable_filters) 
    # Taking the non-keyword filters out of applicable_filters (if any) and applying them as positional arguments to filter()