Hello,
I am working on an app where car owners will list their car and drivers
interested in renting them will make a request to rent the cars…
i basically have three models the *users*(car owners and drivers) *car* listed
by owners, and *rent, *i have a listView to list all the car available and
a detailView for each car, i have a button on the detailed view, when
clicked i want it to take some of the information on the detailed view and
save it in the* rent *model… But i am getting a ValueError (Cannot query
"testuser1": Must be "Listing" instance). But i also need to store the
driver(testuser1 in this case) in the Rent model.
Below are my view.py, models.py and error messages:
*view.py*
class ListingDetailView(DetailView):
model = Listing
def post_rent(self, request, pk, *args, **kwargs):
user = request.User
listing = get_object_or_404(Listing, pk=pk)
rent, created = Rent.objects.get_or_create(
car_owner=listing.car_owner,
driver=request.user,
car_id=listing.pk)
rent.save(request.POST)
messages.info(request, *"Rent request has been made succesfully."*)
return redirect(*'/'*)
*models.py*
class Listing(models.Model):
DEF_YEAR = *'2003'*
CAR_YEAR_CHOICES = [(*'2002'*, *'2002'*), (*'2003'*, *'2003'*), (
*'2004'*, *'2004'*), (*'2005'*, *'2005'*),
(*'2006'*, *'2006'*), (*'2007'*, *'2007'*), (
*'2008'*, *'2008'*), (*'2009'*, *'2009'*),
(*'2010'*, *'2010'*), (*'2011'*, *'2011'*), (
*'2012'*, *'2012'*), (*'2013'*, *'2013'*),
(*'2014'*, *'2014'*), (*'2015'*, *'2015'*), (
*'2016'*, *'2016'*), (*'2017'*, *'2017'*),
(*'2018'*, *'2018'*), (*'2019'*, *'2019'*), (
*'2020'*, *'2020'*), ]
NEW = *'New'*
USED = *'Used'*
OLD = *'Old'*
CAR_CONDITION_CHOICES = [(*'NEW'*, *'New'*), (*'USED'*, *'Used'*), (
*'OLD'*, *'Old'*)]
car_owner = models.ForeignKey(User, on_delete=models.CASCADE)
car_make = models.CharField(max_length=50)
car_model = models.CharField(max_length=50)
car_year = models.CharField(max_length=4, choices=CAR_YEAR_CHOICES,
default=DEF_YEAR)
car_condition = models.CharField(max_length=4,
choices=CAR_CONDITION_CHOICES, default=OLD)
car_pic1 = models.ImageField(default=*'car.png'*, upload_to=
*"car_listing-photos"*)
weekly_charges = models.FloatField()
def __str__(self):
return *f'*{self.car_year} {self.car_make} {self.car_model}*'*
def get_absolute_url(self):
return reverse(*'listing-detail'*, kwargs={*'pk'*: self.pk})
class Rent(models.Model):
car_id = models.BigIntegerField(null=True, blank=True)
car_owner = models.ForeignKey(Listing, on_delete=models.SET_NULL,
null=True, blank=True)
driver = models.ForeignKey(User, on_delete=models.SET_NULL, null=True,
blank=True)
start_date = models.DateField(null=True, blank=True)
end_date = models.DateField(null=True, blank=True)
approved = models.BooleanField(default=False)
*listing_detail.html*
<form method="POST">
{% csrf_token %}
<button type="submit" name="hire-car" class="btn btn-primary">Rent
Car</button>
</form>
*Error Message*
*ValueError at /listing/2/*
Cannot query "testuser1": Must be "Listing" instance.
*Request Method:*
POST
*Request URL:*
http://127.0.0.1:8000/listing/2/
*Django Version:*
3.1
*Exception Type:*
ValueError
*Exception Value:*
Cannot query "testuser1": Must be "Listing" instance.
*More Error Dump:*
Environment:
Request Method: POST
Request URL: http://127.0.0.1:8000/listing/2/
Django Version: 3.1
Python Version: 3.8.5
Installed Applications:
['accounts.apps.AccountsConfig',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'app.apps.AppConfig',
'crispy_forms']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']
Traceback (most recent call last):
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/core/handlers/exception.py",
line 47, in inner
response = get_response(request)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/core/handlers/base.py",
line 179, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/views/generic/base.py",
line 73, in view
return self.dispatch(request, *args, **kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/views/generic/base.py",
line 101, in dispatch
return handler(request, *args, **kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/app/views.py",
line 32, in post
rent, created = Rent.objects.get_or_create(
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/manager.py",
line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/query.py",
line 573, in get_or_create
return self.get(**kwargs), False
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/query.py",
line 418, in get
clone = self._chain() if self.query.combinator else self.filter(*args,
**kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/query.py",
line 942, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/query.py",
line 962, in _filter_or_exclude
clone._filter_or_exclude_inplace(negate, *args, **kwargs)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/query.py",
line 969, in _filter_or_exclude_inplace
self._query.add_q(Q(*args, **kwargs))
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/sql/query.py",
line 1358, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/sql/query.py",
line 1377, in _add_q
child_clause, needed_inner = self.build_filter(
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/sql/query.py",
line 1292, in build_filter
self.check_related_objects(join_info.final_field, value, join_info.opts)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/sql/query.py",
line 1119, in check_related_objects
self.check_query_object_type(value, opts, field)
File
"/Users/ChuzzyOfficial/PycharmProjects/djangoProject/instarydes/.venv/lib/python3.8/site-packages/django/db/models/sql/query.py",
line 1100, in check_query_object_type
raise ValueError(
Exception Type: ValueError at /listing/2/
Exception Value: Cannot query "testuser1": Must be "Listing" instance.
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