Django (DRF) fails to POST data to url with similar path - python

In my url conf I have two similar patterns:
urlpatterns = [
path('chat/', views.chat), # create chat
path('chat/message/', views.message), # create message
]
The second path works as expect, however, when I try to POST data to chat/ I get error 405 and {"detail":"Method \"POST\" not allowed."} error message. The code in the view works, if I modify chat/ to something more specific like chat/create/ then everything works fine. However, this is not what I want to do. I thought django would match the first URL that matches the request. Why is this happening? It this bug or expected behavior?

I have run into a similar issue. I created a new nested_route decorator that acts a lot like list_route and detail_route. I usually redirect to another viewset to handle the nested path. The issue was that the stream was being read too early (by the parent viewset dispatch), so I needed to ensure that the initialize_request function was only called once for a given request.
Working off of #rsalmaso's comment above, I overrode the initialize_request method in the children viewsets with the following.
def initialize_request(self, request, *args, **kwargs):
if not isinstance(request, Request):
request = super().initialize_request(request, *args, **kwargs)
return request
This works fine, but I think having some sort of attribute for either ignoring the initialize_request function within dispatch or having a global check to only run initialize_request iff isinstance(request, rest_framework.request.Request) == False. I'm happy to prepare the PR with tests if that could be acceptable.

Related

405 method not allowed, Django + ngrok, only on my local machine

This is a legacy project that I'm working with other guys in my current job.
and is doing a very strange behavior that I cannot understand.
It's returning 405 http response status, which does not make sense, because this view already accepts POST requests
I would share a couple of snippets, I just detected that happens just in the comment that I would mark.
this is the view file, that actually accepts both methods GET and POST
#csrf_exempt
#load_checkout
#validate_cart
#validate_is_shipping_required
#require_http_methods(["GET", "POST"])
def one_step_view(request, checkout):
"""Display the entire checkout in one step."""
this is the decorator that modifies the response, and returns 405.
def load_checkout(view):
"""Decorate view with checkout session and cart for each request.
Any views decorated by this will change their signature from
`func(request)` to `func(request, checkout, cart)`."""
#wraps(view)
#get_or_empty_db_cart(Cart.objects.for_display())
def func(request, cart):
try:
session_data = request.session[STORAGE_SESSION_KEY]
except KeyError:
session_data = ''
tracking_code = analytics.get_client_id(request)
checkout = Checkout.from_storage(
session_data, cart, request.user, tracking_code)
response = view(request, checkout, cart) # in this response it returns 405.
if checkout.modified:
request.session[STORAGE_SESSION_KEY] = checkout.for_storage()
return response
return func
Any idea or clue when I can start to find out the problem?.
for the record: I didn't code this, this was working a couple of days ago, and its just happening in my local environment, on stage and production, and even the local of others developers are working just fine. I have all the requirements and the dependencies, and are updated.
BTW I'm using ngrok for tunneling
--
if your front-end use different HOST && PORT
you need to add CROS in Django app

Django Rest Framework gives 302 in Unit tests when force_login() on detail view?

I'm using Django Rest Framework to serve an API. I've got a couple tests which work great. To do a post the user needs to be logged in and I also do some checks for the detail view for a logged in user. I do this as follows:
class DeviceTestCase(APITestCase):
USERNAME = "username"
EMAIL = 'a#b.com'
PASSWORD = "password"
def setUp(self):
self.sa_group, _ = Group.objects.get_or_create(name=settings.KEYCLOAK_SA_WRITE_PERMISSION_NAME)
self.authorized_user = User.objects.create_user(self.USERNAME, self.EMAIL, self.PASSWORD)
self.sa_group.user_set.add(self.authorized_user)
def test_post(self):
device = DeviceFactory.build()
url = reverse('device-list')
self.client.force_login(self.authorized_user)
response = self.client.post(url, data={'some': 'test', 'data': 'here'}, format='json')
self.client.logout()
self.assertEqual(status.HTTP_201_CREATED, response.status_code)
# And some more tests here
def test_detail_logged_in(self):
device = DeviceFactory.create()
url = reverse('device-detail', kwargs={'pk': device.pk})
self.client.force_login(self.authorized_user)
response = self.client.get(url)
self.client.logout()
self.assertEqual(status.HTTP_200_OK, response.status_code, 'Wrong response code for {}'.format(url))
# And some more tests here
The first test works great. It posts the new record and all checks pass. The second test fails though. It gives an error saying
AssertionError: 200 != 302 : Wrong response code for /sa/devices/1/
It turns out the list view redirects the user to the login screen. Why does the first test log the user in perfectly, but does the second test redirect the user to the login screen? Am I missing something?
Here is the view:
class APIAuthGroup(InAuthGroup):
"""
A permission to allow all GETS, but only allow a POST if a user is logged in,
and is a member of the slimme apparaten role inside keycloak.
"""
allowed_group_names = [settings.KEYCLOAK_SA_WRITE_PERMISSION_NAME]
def has_permission(self, request, view):
return request.method in SAFE_METHODS \
or super(APIAuthGroup, self).has_permission(request, view)
class DevicesViewSet(DatapuntViewSetWritable):
"""
A view that will return the devices and makes it possible to post new ones
"""
queryset = Device.objects.all().order_by('id')
serializer_class = DeviceSerializer
serializer_detail_class = DeviceSerializer
http_method_names = ['post', 'list', 'get']
permission_classes = [APIAuthGroup]
Here is why you are getting this error.
Dependent Libraries
I did some searching by Class Names to find which libraries you were using so that I can re-create the problem on my machine. The library causing the problem is the one called keycloak_idc. This library installs another library mozilla_django_oidc which would turn out to be the reason you are getting this.
Why This Library Is Causing The Problem
Inside the README file of this library, it gives you instructions on how to set it up. These are found in this file. Inside these instructions, it instructed you to add the AUTHENTICATION_BACKENDS
AUTHENTICATION_BACKENDS = [
'keycloak_oidc.auth.OIDCAuthenticationBackend',
...
]
When you add this authentication backend, all your requests pass through a Middleware defined inside the SessionRefresh class defined inside mozilla_django_oidc/middleware.py. Inside this class, the method process_request() is always called.
The first thing this method does is call the is_refreshable_url() method which always returns False if the request method was POST. Otherwise (when the request method is GET), it will return True.
Now the body of this if condition was as follows.
if not self.is_refreshable_url(request):
LOGGER.debug('request is not refreshable')
return
# lots of stuff in here
return HttpResponseRedirect(redirect_url)
Since this is a middleware, if the request was POST and the return was None, Django would just proceed with actually doing your request. However when the request is GET and the line return HttpResponseRedirect(redirect_url) is triggered instead, Django will not even proceed with calling your view and will return the 302 response immediately.
The Solution
After a couple of hours debugging this, I do not the exact logic behind this middleware or what exactly are you trying to do to provide a concrete solution since this all started based off guess-work but a naive fix can be that you remove the AUTHENTICATION_BACKENDS from your settings file. While I feel that this is not acceptable, maybe you can try using another library that accomplishes what you're trying to do or find an alternative way to do it. Also, maybe you can contact the author and see what they think.
So i guess you have tested this and you get still the same result:
class APIAuthGroup(InAuthGroup):
def has_permission(self, request, view):
return True
Why do you use DeviceFactory.build() in the first test and DeviceFactory.create() in the second?
Maybe a merge of the two can help you:
def test_get(self):
device = DeviceFactory.build()
url = reverse('device-list')
response = self.client.get(url)
self.assertEqual(status.HTTP_200_OK, response.status_code)
Is this a problem with the setUp() method? From what I see, you may be setting self.authorize_user to a user that was already created on the first test.
Instead, I would create the user on each test, making sure that the user doesn't exist already, like so:
user_exists = User.objects.filter(username=self.USERNAME, email=self.EMAIL).exists()
if not user_exists:
self.authorize_user = User.objects.create_user....
That would explain why your first test did pass, why your second didn't, and why #anupam-chaplot's answer didn't reproduce the error.
Your reasoning and code looks ok.
However you are not giving the full code, there must be error you are not seeing.
Suspicious fact
It isn't be default 302 when you are not logged in.
(#login_required, etc redirects but your code doesn't have it)
Your APIAuthGroup permission does allow GET requests for non-logged-in user ( return request.method in SAFE_METHODS), and you are using GET requests (self.client.get(url))
So it means you are not hitting the endpoint that you think you are hitting (your get request is not hitting the DevicesViewSet method)
Or it could be the case you have some global permission / redirect related setting in your settings.py which could be DRF related..
eg :
REST_FRAMEWORK = {
'DEFAULT_PERMISSION_CLASSES': [
'rest_framework.permissions.IsAuthenticated',
]
}
Guess
url = reverse('device-detail', kwargs={'pk': device.pk})
might not point to the url you are thinking..
maybe there's another url (/sa/devices/1/) that overrides the viewset's url. (You might have a django view based url)
And I didn't address why you are getting redirected after force_login.
If it's indeed login related redirect, all I can think of is self.authorized_user.refresh_from_db() or refreshing the request ..
I guess some loggin related property (such as session, or request.user) might point to old instance .. (I have no evidence or fact this can happen, but just a hunch) and you better off not logging out/in for every test case)
You should make a seperate settings file for testing and add to the test command --settings=project_name.test_settings, that's how I was told to do.

Convert GET parameters to POST data on a Request object in Django REST Framework

I am in the process of rewriting the backend of an internal website from PHP to Django (using REST framework).
Both versions (PHP and Django) need to be deployed concurrently for a while, and we have a set of software tools that interact with the legacy website through a simple AJAX API. All requests are done with the GET method.
My approach so far to make requests work on both sites was to make a simple adapter app, routed to 'http://<site-name>/ajax.php' to simulate the call to the Ajax controller. Said app contains one simple function based view which retrieves data from the incoming request to determine which corresponding Django view to call on the incoming request (basically what the Ajax controller does on the PHP version).
It does work, but I encountered a problem. One of my API actions was a simple entry creation in a DB table. So I defined my DRF viewset using some generic mixins:
class MyViewSet(MyGenericViewSet, CreateModelMixin):
# ...
This adds a create action routed to POST requests on the page. Exactly what I need. Except my incoming requests are using GET method... I could write my own create action and make it accept GET requests, but in the long run, our tools will adapt to the Django API and the adapter app will no longer be needed so I would rather have "clean" view sets and models. It makes more sense to use POST for such an action.
In my adapter app view, I naively tried this:
request.method = "POST"
request.POST = request.GET
Before handing the request to the create view. As expected it did not work and I got a CSRF authentication failure message, although my adapter app view has a #csrf_exempt decorator...
I know I might be trying to fit triangle in squares here, but is there a way to make this work without rewriting my own create action ?
You can define a custom create method in your ViewSet, without overriding the original one, by utilizing the #action decorator that can accept GET requests and do the creation:
class MyViewSet(MyGenericViewSet, CreateModelMixin):
...
#action(methods=['get'], detail=False, url_path='create-from-get')
def create_from_get(self, request, *args, **kwargs):
# Do your object creation here.
You will need a Router in your urls to connect the action automatically to your urls (A SimpleRouter will most likely do).
In your urls.py:
router = SimpleRouter()
router.register('something', MyViewSet, base_name='something')
urlpatterns = [
...
path('my_api/', include(router.urls)),
...
]
Now you have an action that can create a model instance from a GET request (you need to add the logic that does that creation though) and you can access it with the following url:
your_domain/my_api/something/create-from-get
When you don't need this endpoint anymore, simply delete this part of the code and the action seizes to exist (or you can keep it for legacy reasons, that is up to you)!
With the advice from all answers pointing to creating another view, this is what I ended up doing. Inside adapter/views.py:
from rest_framework.settings import api_settings
from rest_framework.decorators import api_view, renderer_classes
from rest_framework.response import Response
from rest_framework import status
from mycoreapp.renderers import MyJSONRenderer
from myapp.views import MyViewSet
#api_view(http_method_names=["GET"])
#renderer_classes((MyJSONRenderer,))
def create_entity_from_get(request, *args, **kwargs):
"""This view exists for compatibility with the old API only.
Use 'POST' method directly to create a new entity."""
query_params_copy = request.query_params.copy()
# This is just some adjustments to make the legacy request params work with the serializer
query_params_copy["foo"] = {"name": request.query_params.get("foo", None)}
query_params_copy["bar"] = {"name": request.query_params.get("bar", None)}
serializer = MyViewSet.serializer_class(data=query_params_copy)
serializer.is_valid(raise_exception=True)
serializer.save()
try:
headers = {'Location': str(serializer.data[api_settings.URL_FIELD_NAME])}
except (TypeError, KeyError):
headers = {}
return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
Of course I have obfuscated the names of everything specific to my project. Basically I reproduced almost exactly (except for a few tweaks to my query params) what happens in the create, perform_create and get_success_header methods of the DRF mixin CreateModelMixin in a single function based DRF view. Being just a standalone function it can sit in my adapter app views so that all legacy API code is sitting in one place only, which was my intent with this question.
You can write a method for your viewset (custom_get) which will be called when a GET call is made to your url, and call your create method from there.
class MyViewSet(MyGenericViewSet, CreateModelMixin):
...
def custom_get(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
And in your urls.py, for your viewset, you can define that this method needs to be called on a GET call.
#urls.py
urlpatterns = [
...
url(r'^your-url/$', MyViewSet.as_view({'get': 'custom_get'}), name='url-name'),
]
As per REST architectural principles request method GET is only intended to retrieve the information. So, we should not perform a create operation with request method GET. To perform the create operation use request method POST.
Temporary Fix to your question
from rest_framework import generics, status
class CreateAPIView(generics.CreateView):
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.query_params)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
headers = self.get_success_headers(serializer.data)
return Response(
serializer.data,
status=status.HTTP_201_CREATED,
headers=headers)
def get(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)
Please refer below references for more information.
https://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html
https://learnbatta.com/blog/introduction-to-restful-apis-72/

Pass data from django middleware.process_view to the template context

I have a custom middleware and during its process_view I get some token. And I need to pass this token to the rendered result html.
I thought that context_processor is a good place to modify context, but looks like it's hard to pass some data from middleware into processor.
But it seems that the only way to communicate for process_view and context processor is request object. And if set any field to the request I get 'WSGIRequest' object does not support item assignment' error. Here is a pieces of code:
def process_view(self, request, view_func, view_args, view_kwargs):
...
with log(request, view_func.__name__, info) as id:
request['TOKEN_ID'] = logger.get().get_id() #here is an error
response = view_func(request, *view_args, **view_kwargs)
So, looks like I'm doing something wrong. Is there a way to communicate middleware.process_view and context_processor? Or I should change another way to pass data into html from middleware?
That error is raised when you try and use dictionary item assignment:
request['my_key'] = 'my_value'
But the request is not a dictionary, it is an object. As with all objects - like the Django models which you must be familiar with - you need to set attributes, not items.
request.my_attribute = 'my_value'
(Next time, please show the code you used and the full traceback you got.)

Django url validation

HI,
I want to validate my urls whether they are post or get with caring the proper data.So i want to validate these urls before they call to respective views.So i am willing to write the some kind of middleware between view and urls so that i can keep safe the system.I am not aware how do i pass the data through middleware code to view.In middle ware i will write the unittest code.which will validate the urls if valid then will pass to the respective view other wise happy to say 404 .So can any buddy suggest me how do i handle the case.Or may be their is another alternative best way to do this validation.
Thanks to all.
You should really be checking for request type in your views, and not in a middleware. As I mentioned in the comments above, you can't tell whether a request is a POST message from the URL alone, let alone determine what POST data it carries.
Checking the request type within a view is very straight-forward -- simple check that request.method is equal to "GET" or "POST".
If you're doing this often, a short cut would be to create a decorator which does this check for you. For example, the following decorator checks that a GET request was used to call this view, or else return an HttpResponseBadRequest object (status code 400):
# untested code, use with care
def require_GET(view_func):
def wrap(request, *args, **kwargs):
if request.method != "GET":
return HttpResponseBadRequest("Expecting GET request")
return view_func(request, *args, **kwargs)
wrap.__doc__ = view_func.__doc__
wrap.__dict__ = view_func.__dict__
wrap.__name__ = view_func.__name__
return wrap
You can then simply prepend your view function with #require_GET and the check will be done whever the view is called. E.g.
#require_GET
def your_view(request):
# ...
You can do the same for POST.
Here's an example decorator checking for POST request which takes an optional list of fields that must be provided with the POST request.
# again, untested so use with care.
def require_POST(view_func, required_fields=None):
def wrap(request, *args, **kwargs):
if request.method != "POST":
return HttpResponseBadRequest("Expecting POST request")
if required_fields:
for f in required_fields:
if f not in request.POST:
return HttpResponseBadRequest("Expecting field %s" % f)
return view_func(request, *args, **kwargs)
wrap.__doc__ = view_func.__doc__
wrap.__dict__ = view_func.__dict__
wrap.__name__ = view_func.__name__
return wrap
Use like this:
#require_POST
def another_view(request):
# ...
or:
#require_POST(required_fields=("username", "password"))
def custom_login_view(request):
# ...
Update
OK, my bad. I've just reinvented wheel.
Django already provides the #require_GET and #require_POST decorators. See django.views.decorators.http.
Like others said, you must do it in your view, or maybe you must say what you are trying to do for the best...
Anyway, you can not create a responce object in process_request , you can only add variables or change variables on the related request, like the sessionid variable used by django, or any such thing... Or update any existing request variables...
So, you must use process_view, which is triggered after process_request and just before your related view function is executed.Since you have request object at hand, you can check GET or POST data by using request.GET or request.POST.
For doing this, you must add your middle class to MIDDLEWARE_CLASSES in settings.py and write a proper middleware process_view function. For writing middlewares see middleware documentation and check existing middlewares of django. Or tell me what you are rtying to do...

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