Where are variables passed into the view in Django? - django

I'm refactoring code in a Django view. I'm working with a view with the below arguments:
def title_views(request, key, group, sort):
group = get_object_or_404(Group, group=group, main_id = key)
default_sort = sort
I know by default each view should have the request argument. But in terms of key, group, sort, where can I expect these items to be passed? Is it through the template that the view is called in? I come here for help because the documentation isn't that clear on this, at least in my experience.
Thanks!

These are URL parameters. Likely the URL that links to this view looks like:
path('<str:key>/<str:group>/<str:sort>/', title_views)
or with a regex, something like:
re_path(r'(?P<key>\w+)/(?P<title>\w+)/(?P<sort>\w+)/')
If you thus visit a page like foo/bar/qux/ it will pattern match on the path, and thus call the function with 'foo' for key, 'bar' for title, and 'qux' for sort.
Usually the URL parameters thus contain data that determine how to filter, order and render the content.

Related

Force django querystring in url

Say you have a url like this:
/cats/?filter=kittens
Is it possible to build a django url pattern that forces the use of the querystring?
Currently I have:
url(r'^/cats/$', views.CatsListView.as_view(), name='cats')
Now I want to add the querystring and get a different view, something like this:
url(r'^/cats/?filter=(?P<filter>.+?)$', views.CatsFilteredListView.as_view(), name='cats-filtered')
Is it possible to do something like this and still keep the querystring in the GET parameter of the request?
Remember that this is just a testcase, I, and you should too, know that filtering like probably this isn't the way to go..
Short answer: no, it's not possible. Django url patterns match only on the "path" componant of the url, period.
No, it's not possible to do this. If you really need two separate views, you can write a view that dispatches the correct view.
def cat_list_view(request, *args, **kwargs):
if 'filter' in request.GET:
return cat_list_filter_view(request, *args, **kwargs)
else:
return cat_list_unfiltered_view(request, *args, **kwargs)
However, for your example of CatsListView and CatsFilteredListView there is probably a better way to combine the views. For example you might be able to do the filtering in the get_queryset method.
While it is true that you cannot manipulate the path component like that, you can pass a dictionary in. It's a 3rd unnamed argument.
This approach can be useful if you want to use the same view for multiple resources, and pass data to configure its behaviour in each case (below we supply a different template in each case).
path('url/', views.my_reused_view, {'my_template_name': 'some_path'}, name='aurl'),
path('anotherurl/', views.my_reused_view, {'my_template_name': 'another_path'}, name='anotherurl'),
Note: Both extra options and named captured patterns are passed to the view as named arguments. If you use the same name for both a captured pattern and an extra option then only the captured pattern value will be sent to the view (the value specified in the additional option will be dropped).
Courtesy of https://developer.mozilla.org/en-US/docs/Learn/Server-side/Django/Generic_views

Django: Multiple parameters in URLs reverse resolution without querystrings or captured parameters

Without using query strings (like ?case=/2/), nor captured parameters in the url conf (like ?P) (so they dont show up in the url),
is there a way to pass parameters to a view function when using URLs reverse resolution?
Hopefully an example will clarify my question:
With captured parameters I could do:
views.py
...
return HttpResponseRedirect(reverse('videos:show_details', args=[video.id]))
urls.py
...
url(r'^club/(?P\d+)/$',views.details, name='show_details'),
...
But what if the view details needs / accepts more parameters, for example:
def details (request, video_id, director='', show_all=True):
And we dont want them to show up in the url?
Any way of using args or kwargs without them being in the url?
Im sure Im missing something trivial here :S
Hopefully someone can point me in the right direction.
Thanks!
I'm not sure this is what you mean, but you can pass extra arguments to the url pattern. This allows multiple urls that point to the same view to use different arguments:
url(r'^club/(?P<pk>\d+)/$', views.details, kwargs={'show_all': False}, name='show_details')

Django context processors and URL arguments

I have some code that is repeated at the start of my Django views. It basically just adds some variables to the context, but based on the URL argument, e.g.
def someView(request, id):
target = Target.objects.get(id=id)
# name will be added to ctx
name = target.name
(there are more attributes added and other attributes from related models, but this gives the general idea --- There are quite a few lines of repeat code at the start of each view)
I thought I could make my code more DRY by taking advantage of Django's context processors, but it would seem these don't access to the URL arguments?
Is there another way to avoid these repeat lines? Maybe middleware or something else?
You can access the URL parameters via request through the resolver_match attribute. So for instance you can do request.resolver_match.kwargs['id'] to get the ID kwarg.

In Django, how do I deal with an "or" in the url regex once I get to the view?

I'm just learning Django, and am getting stuck with some url logic. I'm trying to allow either a category name or id in the url:
...
url(r'^(?P<booze_q>\w+|\d+)/$','glasses.views.booze'),
...
And then in thew view, only deal with that result once. However, if the url is a string - in this case, Whiskey, I get an error for trying to pass a string where an int is expected. This is the closest I've gotten so far:
def booze(request, booze_q):
booze = get_object_or_404(Booze,Q(pk=booze_q)|Q(name=booze_q))
return render_to_response('booze/detail.html', {'booze': booze})
But this returns an error: invalid literal for int() with base 10: 'Whiskey'
I'm sure it's a pretty easy thing, but this is my first Django app, so any help would be appreciated.
tl;dr: End result, I'd like mysite.com/1/ or mysite.com/Whiskey/ to both call the glasses.views.booze view, and get the object with id=1 or name=Whiskey
This is a common scenario you'll encounter quite often, which is typically handled by resorting to multiple arguments and having views behave differently based on which of the view arguments are then present or not.
What you do is first define a URL pattern that uniquely matches each specific case and then let Django's URL resolver set the arguments accordingly based on which of the patterns was matched.
Here's an example with a class based view, that performs two different queries based on which of the two keyword arguments, booze_id or booze_name, is set:
url(r'^(?P<booze_id>\d+)/$', BoozeDetailView.as_view()),
url(r'^(?P<booze_name>\w+)/$', BoozeDetailView.as_view()),
class BoozeDetailView(DetailView):
model = Booze
def get_object(self):
booze_id = self.kwargs.get('booze_id', None)
booze_name = self.kwargs.get('booze_name', None)
if booze_id:
return self.model.objects.get(id=booze_id)
else:
return self.model.objects.get(name=booze_name)
You will always get a string, even if the string contains a number.
1) You should not have a parameter that could be either an id or something else. One day you will enter an item whose name is a number and your app will fail.
2) When querying for pk with a string django automatically tries to convert it into an integer. You'll have to handle the non-pk case before constructing that query.

Django: grabbing parameters

I'm having the hardest time with what should be super simple. I can't grab the passed parameters in django.
In the browser I type:
http://localhost:8000/mysite/getst/?term=hello
My url pattern is:
(r'^mysite/getst/$', 'tube.views.getsearchterms')
My View is
def getsearchterms(request):
my_term = some_way_to_get_term
return HttpResponse(my_term)
In this case it should return "hello". I am calling the view, but a blank value is returned to me. I've tried various forms of GET....
What should some_way_to_get_term be?
The get parameters can be accesses like any dictionary:
my_term = request.GET['term']
my_term = request.GET.get('term', 'my default term')
By using arbitrary arguments after ? and then catching them with request.GET['term'], you're missing the best features of Django urls module : a consistent URL scheme
If "term" is always present in this URL call it must be meaningful to your application,
so your url rule could look like :
(r'^mysite/getst/(?P<term>[a-z-.]+)/', 'tube.views.getsearchterms')
That means :
That you've got a more SEO-FRIENDLY AND stable URL scheme (no ?term=this&q=that inside)
That you can catch your argument easily in your view :
Like this
def getsearchterms(request,term):
#do wahtever you want with var term
print term