Django view function execution jumps to different function - html

Question

I'm adding new applications to an existing Django project, and encountered something I am unable to debug. The callback error is "AttributeError: 'QuerySet' object has no attribute 'META'", but I'm not sure that's what's going on. I've written 4 of these apps for different API objects today, and had no issues. When I add print() debug messages to the functions, what I find is that the execution seems to be jumping out of my lead_lists view function and into my lists view function before it errors.
This is my list.views.py
def list(request):
print("we're in lists view")
lists = List.objects.all()
print("lists saved for context")
context = {'lists': lists}
print("context created")
return render(request, 'list.html', context) # fails here
def load_lists(request):
api_lists = services.get_lists()
print("api lists loaded")
db_list_ids = list(List.objects.values_list('list_id', flat=True)) # jumps out of function here
print("db lists loaded") # this never prints
print(f"db_list_ids: {db_list_ids}")
for api_list in api_lists:
if api_list['id'] not in db_list_ids:
api_list = services.transform_list(api_list)
form = ListModelForm(api_list)
if form.is_valid():
form.save
else:
return HttpResponse(form.errors)
print("exited load loop")
lists = List.objects.all()
print("load lists objects saved")
context = {'lists': lists}
print("load lists context saved")
return render(request, 'load_lists.html', context)
The expected result is, when I navigate to /list/load it runs the load_lists view function. Here is the output I get from the console.
we're in lists view
lists saved for context
context created
[31/Jul/2019 16:20:32] "GET /list/ HTTP/1.1" 200 2458
api lists loaded
we're in lists view
lists saved for context
context created
Internal Server Error: /list/load/
Traceback (most recent call last):
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
response = self.process_exception_by_middleware(e, request)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\David.Wilcox\ongage-django\ongage\list\views.py", line 19, in load_lists
db_list_ids = list(List.objects.values_list('list_id', flat=True))
File "C:\Users\David.Wilcox\ongage-django\ongage\list\views.py", line 14, in list
return render(request, 'list.html', context)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\shortcuts.py", line 36, in render
content = loader.render_to_string(template_name, context, request, using=using)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\template\loader.py", line 62, in render_to_string
return template.render(context, request)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\template\backends\django.py", line 61, in render
return self.template.render(context)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\template\base.py", line 169, in render
with context.bind_template(self):
File "c:\users\david.wilcox\appdata\local\programs\python\python37-32\Lib\contextlib.py", line 112, in __enter__
return next(self.gen)
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\template\context.py", line 246, in bind_template
updates.update(processor(self.request))
File "C:\Users\David.Wilcox\ongage-django\venv\lib\site-packages\django\template\context_processors.py", line 40, in debug
if settings.DEBUG and request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS:
AttributeError: 'QuerySet' object has no attribute 'META'
[31/Jul/2019 16:20:36] "GET /list/load/ HTTP/1.1" 500 103930
I originally thought it wasn't playing nicely due to the usage of the word 'list', so I refactored and renamed my variables, but the error is the same.

Answer 1

Short answer: please do not name your views after Python builtins like list. You can rename the view function to view_lists.
You here defined a function named list. As a result, if you later use list(List.objects.values_list('list_id', flat=True)) in your load_lists view, you will indeed call the view function, and not the builtin function, since that identifier now points to your view function.
You can for example rename it to view_lists, like:
# rename view function
def view_lists(request):
return render(request, 'list.html', {'lists': List.objects.all()})
def load_lists(request):
api_lists = services.get_lists()
db_list_ids = list(List.objects.values_list('list_id', flat=True))
print(f"db_list_ids: {db_list_ids}")
for api_list in api_lists:
if api_list['id'] not in db_list_ids:
api_list = services.transform_list(api_list)
form = ListModelForm(api_list)
if form.is_valid():
form.save()
else:
return HttpResponse(form.errors)
lists = List.objects.all()
return render(request, 'load_lists.html', context = {'lists': lists})
Note that you need to call the save() function on your form, so form.save(), not form.save.
PEP-8 recommends adding a trailing underscore if there is no better name than a builtin one:
If a function argument's name clashes with a reserved keyword, it is generally better to append a single trailing underscore rather than use an abbreviation or spelling corruption. Thus class_ is better than clss. (Perhaps better is to avoid such clashes by using a synonym.)
(...)
If your public attribute name collides with a reserved keyword, append a single trailing underscore to your attribute name. This is preferable to an abbreviation or corrupted spelling. (However, notwithstanding this rule, 'cls' is the preferred spelling for any variable or argument which is known to be a class, especially the first argument to a class method.)