如何处理可选的GET参数？

Question

我有一个GET请求，有时有pk参数，有时还没有。 我想有一个处理它的视图，但是我的编写尝试不成功。以下是我有：

@ajax 
@login_required 
def search_dist(request): 
    try: 
     pk = request.GET.get('pk') 
    except Exception: 
     dist_list = request.user.distributors.all() 
     starts_with = request.GET.get('query') 
     if starts_with: 
      dist_list = request.user.distributors.filter(
       surname__istartswith=starts_with) 
     return render(request, 'distributors/distributors_list.html', {'distributors': dist_list}) 
    else: 
     dist_list = request.user.distributors.filter(
      distributors_of_links=get_object_or_404(Link, pk=pk)) 
     starts_with = request.GET.get('query') 
     if starts_with: 
      dist_list = request.user.distributors.filter(distributors_of_links=get_object_or_404(
       Link, pk=pk)).filter(surname__istartswith=starts_with) 
     return render(request, 'distributors/distributors_list.html', {'distributors': dist_list}) 

我的模型的一部分：

class Distributor(models.Model): 


class Link(models.Model): 
    distributors = models.ManyToManyField(
     Distributor, blank=True, related_name='distributors_of_links') 


class UserProfile(AbstractUser): 
    distributors = models.ManyToManyField(
     Distributor, blank=True, related_name='distributors_of_user') 

与查询：search_dist?query=V我：

GET /distributors/search_dist 404 NOT FOUND 
No Link matches the given query. 

我在做什么错？

Answer 1

pk = request.GET.get('pk') 

不会引发异常。如果pk不在GET中，它会给你None。 所以你的第一个案例从不执行。 试一下：

@ajax 
@login_required 
def search_dist(request): 
    pk = request.GET.get('pk', None) 
    if pk is None: 
     dist_list = request.user.distributors.all() 
     starts_with = request.GET.get('query') 
     if starts_with: 
      dist_list = request.user.distributors.filter(
       surname__istartswith=starts_with) 
     return render(request, 'distributors/distributors_list.html', {'distributors': dist_list}) 
    else: 
     dist_list = request.user.distributors.filter(
      distributors_of_links=get_object_or_404(Link, pk=pk)) 
     starts_with = request.GET.get('query') 
     if starts_with: 
      dist_list = request.user.distributors.filter(distributors_of_links=get_object_or_404(
       Link, pk=pk)).filter(surname__istartswith=starts_with) 
     return render(request, 'distributors/distributors_list.html', {'distributors': dist_list})