Field 'id' expected a number but got 'Henry' (AJAX & DRF) - django

Question

I am trying to get a user's list with an AJAX request and DRF. But get this error:
Field 'id' expected a number but got 'Henry'.
I'd be grateful for any assistance.
AJAX:
const showUserLists = function(map){
let userName = "Henry";
$.ajax({
type: 'GET',
url: '/api/userlist/',
data: {
'username': userName
},
success: function (data) {
data.forEach(item => {
console.log(item.list_name)
$("#userLists").append("<li class=userlist data-name=\"" + item.list_name + "\">" + item.list_name + "</li>")
})
}
});
};
urls.py:
router = DefaultRouter() #need help understanding router register
router.register('userlist', views.UserListViewSet, basename= 'userlist')
views.py
#this shows all lists for a user
class UserListViewSet(viewsets.ModelViewSet):
serializer_class = UserListSerializer
def get_queryset(self):
name = self.request.GET.get('username', None)
return UserList.objects.filter(user=name)
Serializer:
class UserListSerializer(serializers.ModelSerializer): #this is what we worked on on October 1
class Meta:
model = UserList
fields = ['id', 'user', 'list_name']
class VenueListSerializer(serializers.ModelSerializer):
created = serializers.ReadOnlyField()
class Meta:
model = VenueList
fields = ['id', 'title']
Relevant model:
class UserList(models.Model):
list_name = models.CharField(max_length=255)
user = models.ForeignKey(User, on_delete=models.CASCADE) #is this okay?
def __str__(self):
return self.list_name
Traceback
Traceback (most recent call last):
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 1774, in get_prep_value
return int(value)
ValueError: invalid literal for int() with base 10: 'Henry'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/core/handlers/base.py", line 179, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/rest_framework/viewsets.py", line 114, in view
return self.dispatch(request, *args, **kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/rest_framework/views.py", line 505, in dispatch
response = self.handle_exception(exc)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/rest_framework/views.py", line 465, in handle_exception
self.raise_uncaught_exception(exc)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/rest_framework/views.py", line 476, in raise_uncaught_exception
raise exc
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/rest_framework/views.py", line 502, in dispatch
response = handler(request, *args, **kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/rest_framework/mixins.py", line 38, in list
queryset = self.filter_queryset(self.get_queryset())
File "/Users/x/Desktop/Coding/anybody/anybody1/api/views.py", line 33, in get_queryset
return UserList.objects.filter(user=name)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/query.py", line 942, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/query.py", line 962, in _filter_or_exclude
clone._filter_or_exclude_inplace(negate, *args, **kwargs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/query.py", line 969, in _filter_or_exclude_inplace
self._query.add_q(Q(*args, **kwargs))
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1358, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1380, in _add_q
split_subq=split_subq, check_filterable=check_filterable,
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1319, in build_filter
condition = self.build_lookup(lookups, col, value)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1165, in build_lookup
lookup = lookup_class(lhs, rhs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/lookups.py", line 24, in __init__
self.rhs = self.get_prep_lookup()
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/fields/related_lookups.py", line 115, in get_prep_lookup
self.rhs = target_field.get_prep_value(self.rhs)
File "/Users/x/Desktop/Coding/anybody/avenv/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 1778, in get_prep_value
) from e
ValueError: Field 'id' expected a number but got 'Henry'.

Answer 1

Your user is a ForeignKey to the User model, so if you filter on this, it expects the primary key of the User, not the username.
You can however filter on the username of the related User with:
class UserListViewSet(viewsets.ModelViewSet):
serializer_class = UserListSerializer
def get_queryset(self):
name = self.request.GET.get('username', None)
return UserList.objects.filter(user__username=name)
Note: It is normally better to make use of the settings.AUTH_USER_MODEL [Django-doc] to refer to the user model, than to use the User model [Django-doc] directly. For more information you can see the referencing the User model section of the documentation.