Decorator function argument woes
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Mike Dewhirst
Apr 30, 2018, 1:27:52 AM4/30/18
to Django users
I'm pretty sure this is a not-understanding-python
problem rather than a Django problem but here goes ...
In a (FBV) view I'm trying to pass a function in to the login_required decorator. My function is called 'is_login_needed' and I want the login_required decorator to effectively switch itself off if login is not needed.
The scenario is on-line training and if the training instruction has questions with scores then obviously the user needs to login. On the other hand if it is simply a demonstration video or plain blah with no questions/answers/scores it should be viewable by anyone whether they are logged in or not.
My function goes like this and the docstring reveals my understanding ...
So the problem is that manage.py runserver reports an attribute error saying the function (presumably mine) does not have an attribute 'user' ... like this ...
Here is the contrib.auth.decorators.login_required source (preceded by user_passes_test which it calls) from Django 1.11
My reading of the following is that my own 'is_login_needed' function passed in via @login_required(is_login_needed, login_url='login') as the first positional argument is then passed to the 'user_passes_test' decorator as 'test_func' ...
Many thanks for any help
Mike
In a (FBV) view I'm trying to pass a function in to the login_required decorator. My function is called 'is_login_needed' and I want the login_required decorator to effectively switch itself off if login is not needed.
The scenario is on-line training and if the training instruction has questions with scores then obviously the user needs to login. On the other hand if it is simply a demonstration video or plain blah with no questions/answers/scores it should be viewable by anyone whether they are logged in or not.
My function goes like this and the docstring reveals my understanding ...
def is_login_needed(user):
""" the login_required decorator has a user_passes_test() function as
its first arg. If it returns True, no login is required. user.login_here
is always set equal to the selected course.login_needed. For courses
needing a login, self.is_authenticated must be True. For courses not
needing a login, self.is_authenticated may return anything but this
function passed to the login_required decorator must return True
"""
if not user.login_here:
return True
So the problem is that manage.py runserver reports an attribute error saying the function (presumably mine) does not have an attribute 'user' ... like this ...
<earlier runserver traceback lines snipped> File "C:\Users\mike\envs\xxct3\train\course\urls.py", line 8, in <module>
from .views import (finished_course_view, course_view, index_view,
File "C:\Users\mike\envs\xxct3\train\course\views.py", line 172, in <module>
def course_view(request, pk=None, slug=None):
File "C:\Users\mike\envs\xxct3\lib\site-packages\django\contrib\auth\decorators.py", line 22, in _wrapped_view
if test_func(request.user):
AttributeError: 'function' object has no attribute 'user'If that 'function' is my 'is_login_needed' function I'm inclined to think it obviously has a 'user' attribute.
Here is the contrib.auth.decorators.login_required source (preceded by user_passes_test which it calls) from Django 1.11
My reading of the following is that my own 'is_login_needed' function passed in via @login_required(is_login_needed, login_url='login') as the first positional argument is then passed to the 'user_passes_test' decorator as 'test_func' ...
def user_passes_test(test_func, login_url=None, redirect_field_name=REDIRECT_FIELD_NAME):
"""
Decorator for views that checks that the user passes the given test,
redirecting to the log-in page if necessary. The test should be a callable
that takes the user object and returns True if the user passes.
"""
def decorator(view_func):
@wraps(view_func, assigned=available_attrs(view_func))
def _wrapped_view(request, *args, **kwargs):
if test_func(request.user):
return view_func(request, *args, **kwargs)
path = request.build_absolute_uri()
resolved_login_url = resolve_url(login_url or settings.LOGIN_URL)
# If the login url is the same scheme and net location then just
# use the path as the "next" url.
login_scheme, login_netloc = urlparse(resolved_login_url)[:2]
current_scheme, current_netloc = urlparse(path)[:2]
if ((not login_scheme or login_scheme == current_scheme) and
(not login_netloc or login_netloc == current_netloc)):
path = request.get_full_path()
from django.contrib.auth.views import redirect_to_login
return redirect_to_login(
path, resolved_login_url, redirect_field_name)
return _wrapped_view
return decorator
def login_required(function=None, redirect_field_name=REDIRECT_FIELD_NAME, login_url=None):
"""
Decorator for views that checks that the user is logged in, redirecting
to the log-in page if necessary.
"""
actual_decorator = user_passes_test(
lambda u: u.is_authenticated,
login_url=login_url,
redirect_field_name=redirect_field_name
)
if function:
return actual_decorator(function)
return actual_decoratorCould someone please explain where I'm stuffing up. I reckon I'm confused about which function the AttributeError is complaining.
Many thanks for any help
Mike
Stephen J. Butler
Apr 30, 2018, 1:35:54 AM4/30/18
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@login_required doesn't take a test function. You need to use @user_passes_test directly.
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Mike Dewhirst
Apr 30, 2018, 2:25:56 AM4/30/18
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On 30/04/2018 3:35 PM, Stephen J. Butler wrote:
> @login_required doesn't take a test function. You need to use
> @user_passes_test directly.
Thank you Stephen.
> @login_required doesn't take a test function. You need to use
> @user_passes_test directly.
I thought I'd start another thread to ask about my use case of being
able to require login or not depending on whether the content needed a
login or not ... but ... just as I was thinking about it I had another
look at login_required and thought I'd ask one more question.
Its signature is ...
def login_required(function=None,
redirect_field_name=REDIRECT_FIELD_NAME, login_url=None):
Are you saying that function is the the view function?
M
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Stephen J. Butler
Apr 30, 2018, 2:30:59 AM4/30/18
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Yes. I don't see it in the documentation for login_required, but I believe it's so that you can do something like this in your urls.py:
urlpatterns = [
url(r'^example$', login_required(views.example)),
]
That might be an older way of using the decorator? IDK for sure. But you can see from the code for login_required that the "test" is always a lambda that checks if the user is authenticated; there's no option to override it. If the "function" parameter is present then it is used as the function be wrapped, not the test being done.
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Mike Dewhirst
Apr 30, 2018, 2:38:17 AM4/30/18
to django...@googlegroups.com, Stephen J. Butler
On 30/04/2018 4:30 PM, Stephen J. Butler wrote:
> Yes. I don't see it in the documentation for login_required, but I
> believe it's so that you can do something like this in your urls.py:
>
> urlpatterns = [
> url(r'^example$', login_required(views.example)),
> ]
>
> That might be an older way of using the decorator? IDK for sure. But
> you can see from the code for login_required that the "test" is always
> a lambda that checks if the user is authenticated; there's no option
> to override it. If the "function" parameter is present then it is used
> as the function be wrapped, not the test being done.
That all makes sense. Thanks again
> Yes. I don't see it in the documentation for login_required, but I
> believe it's so that you can do something like this in your urls.py:
>
> urlpatterns = [
> url(r'^example$', login_required(views.example)),
> ]
>
> That might be an older way of using the decorator? IDK for sure. But
> you can see from the code for login_required that the "test" is always
> a lambda that checks if the user is authenticated; there's no option
> to override it. If the "function" parameter is present then it is used
> as the function be wrapped, not the test being done.
Cheers
Mike
>
> On Mon, Apr 30, 2018 at 1:24 AM, Mike Dewhirst <mi...@dewhirst.com.au
> <mailto:mi...@dewhirst.com.au>> wrote:
>
> On 30/04/2018 3:35 PM, Stephen J. Butler wrote:
>
> @login_required doesn't take a test function. You need to use
> @user_passes_test directly.
>
>
> Thank you Stephen.
>
> I thought I'd start another thread to ask about my use case of
> being able to require login or not depending on whether the
> content needed a login or not ... but ... just as I was thinking
> about it I had another look at login_required and thought I'd ask
> one more question.
>
> Its signature is ...
>
> def login_required(function=None,
> redirect_field_name=REDIRECT_FIELD_NAME, login_url=None):
>
> Are you saying that function is the the view function?
>
> M
>
>
> On Mon, Apr 30, 2018 at 12:26 AM, Mike Dewhirst
> <mi...@dewhirst.com.au <mailto:mi...@dewhirst.com.au>
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Mike Dewhirst
Apr 30, 2018, 9:59:47 AM4/30/18
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Stephen
Not really solved except I gave up on decorating when I finally "got"
it. Thanks again.
1. made two new sub-views for the two scenarios and decorated one of
them with login_required
2. factored out all the commonalities into a new undecorated view with
the same name as used in urls.py
3. in the view called from urls.py discovered the necessary determinant
and returned the appropriate sub-view
Works well and it is obvious to me now that this was the right way to
proceed in the first place.
Cheers
Mike
Not really solved except I gave up on decorating when I finally "got"
it. Thanks again.
1. made two new sub-views for the two scenarios and decorated one of
them with login_required
2. factored out all the commonalities into a new undecorated view with
the same name as used in urls.py
3. in the view called from urls.py discovered the necessary determinant
and returned the appropriate sub-view
Works well and it is obvious to me now that this was the right way to
proceed in the first place.
Cheers
Mike
Peter of the Norse
May 7, 2018, 11:42:31 PM5/7/18
to django...@googlegroups.com
Yes, but that’s because all of the arguments are optional. That way you can do:
@login_required
def my_view(request):
…
@login_required(login_url=“/login/“)
def other_view(request):
…
- Peter of the Norse
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