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

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')

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 template throws NoReverseMatch error

I had two methods create and update in the views, in which update takes one argument whereas create does not take any. I have decided to turn them into only one function update_create because they were not that different.
This is how the new method in views looks:
def update_create(request, id=None):
This is my urls.py:
url(r'^(\d+)/update/$|create/$', update_create, name='update_create'),
This is how my template looks in templates/list.html
Create a new event
I got this error when using the above code:
NoReverseMatch at /agenda/list/
Reverse for 'update_create' with arguments '()' and keyword arguments '{}' not found.
But, if I use this in my templates instead (I have added an argument), it works without any errors:
Create a new event
Can someone explain what's happening? Why previous code didn't work, and Why the new code is working?
URL pattern (\d+) expects number to be provided as argument. To resolve the issue simply provide urls like this:
url(r'^(\d+)/update/$', update_create, name='update_create'),
url(r'^update/$', update_create, name='update_create'),
As mariodev pointed out, your url pattern was expecting a digit in front of the url. As such, your first url:
Create a new event
would generate a url like /update, which wasn't a valid url. However, the latter url:
Create a new event
would generate a url like /1/update, which was a valid url.
From the django docs: https://docs.djangoproject.com/en/dev/topics/http/urls/
Basically subsequent arguments get parsed on first come first serve, and passed to your view. Another thing to consider when developing is using explicitly named parameters, as the django docs elaborate on.

How can I pass named arguments to a Django view method?

I have a view method with two additional parameters:
def foo(request, email, token):
...
And I need to use reverse to generate a URL:
...
url = urlresolvers.reverse(
'my_app.views.foo',
kwargs={ 'token': <token>, 'email': <email> })
Is my use of reverse reasonable/acceptable, and
What does the URL pattern for foo look like?
1 - Yes, as far as it goes, but of course it will fail without the urlpattern. You can use either args or kwargs, depending on your case. Here you can use args, as they are both required args from your view function.
2 - Here's a urlpattern to get you going, but the regex is only an example, as I don't know what your regex needs to be.
url(r'^/(?P<email>[-\w]+)/(?P<token>\d{1,2})/$', 'views.foo', name='foo'),
Named urls are a good pattern to get into the habit of doing. You can pass the name to the reverse function too:
url = urlresolvers.reverse(
'foo',
args=['<email>', '<token>']
Yes
It's up to you to write it in your URLconf.
You might want to have a look at Django docs
By your question, though, it's probably better if you run through the tutorial. The third part explains how to write down the URL scheme for your site.

how to prevent the extra slashes comin in the url of the browser

urls.py
url(r'^kebreading/$', 'KEBReading1',name="kebreading"),
url(r'^kebreading/(?P<param>\w*)/(?P<date>\w*)/(?P<year>\w*)/(?P<month>\w*)/$', kEBReading1',name="kebreading")
i have a view which i pass 5 parameters to it. and the same view is being called when i dont pass any parameter. but five slashes gets appended to the url in the browser even wen i don pass any parameters. how to prevent this happening???
You can use the regexp ? sign to create an optional group and use ?: so Django do not pass this group as an *arg parameter
Something like :
url(r'^kebreading/(?:(?P<param>\w*)/(?P<date>\w*)/(?P<year>\w*)/(?P<month>\w*)/)?$', kEBReading1',name="kebreading")
There is a similar question #2325433

Capturing URL parameters in request.GET

I am currently defining regular expressions in order to capture parameters in a URL, as described in the tutorial. How do I access parameters from the URL as part the HttpRequest object?
My HttpRequest.GET currently returns an empty QueryDict object.
I'd like to learn how to do this without a library, so I can get to know Django better.
When a URL is like domain/search/?q=haha, you would use request.GET.get('q', '').
q is the parameter you want, and '' is the default value if q isn't found.
However, if you are instead just configuring your URLconf**, then your captures from the regex are passed to the function as arguments (or named arguments).
Such as:
(r'^user/(?P<username>\w{0,50})/$', views.profile_page,),
Then in your views.py you would have
def profile_page(request, username):
# Rest of the method
To clarify camflan's explanation, let's suppose you have
the rule url(regex=r'^user/(?P<username>\w{1,50})/$', view='views.profile_page')
an incoming request for http://domain/user/thaiyoshi/?message=Hi
The URL dispatcher rule will catch parts of the URL path (here "user/thaiyoshi/") and pass them to the view function along with the request object.
The query string (here message=Hi) is parsed and parameters are stored as a QueryDict in request.GET. No further matching or processing for HTTP GET parameters is done.
This view function would use both parts extracted from the URL path and a query parameter:
def profile_page(request, username=None):
user = User.objects.get(username=username)
message = request.GET.get('message')
As a side note, you'll find the request method (in this case "GET", and for submitted forms usually "POST") in request.method. In some cases, it's useful to check that it matches what you're expecting.
Update: When deciding whether to use the URL path or the query parameters for passing information, the following may help:
use the URL path for uniquely identifying resources, e.g. /blog/post/15/ (not /blog/posts/?id=15)
use query parameters for changing the way the resource is displayed, e.g. /blog/post/15/?show_comments=1 or /blog/posts/2008/?sort_by=date&direction=desc
to make human-friendly URLs, avoid using ID numbers and use e.g. dates, categories, and/or slugs: /blog/post/2008/09/30/django-urls/
Using GET
request.GET["id"]
Using POST
request.POST["id"]
Someone would wonder how to set path in file urls.py, such as
domain/search/?q=CA
so that we could invoke query.
The fact is that it is not necessary to set such a route in file urls.py. You need to set just the route in urls.py:
urlpatterns = [
path('domain/search/', views.CityListView.as_view()),
]
And when you input http://servername:port/domain/search/?q=CA. The query part '?q=CA' will be automatically reserved in the hash table which you can reference though
request.GET.get('q', None).
Here is an example (file views.py)
class CityListView(generics.ListAPIView):
serializer_class = CityNameSerializer
def get_queryset(self):
if self.request.method == 'GET':
queryset = City.objects.all()
state_name = self.request.GET.get('q', None)
if state_name is not None:
queryset = queryset.filter(state__name=state_name)
return queryset
In addition, when you write query string in the URL:
http://servername:port/domain/search/?q=CA
Do not wrap query string in quotes. For example,
http://servername:port/domain/search/?q="CA"
def some_view(request, *args, **kwargs):
if kwargs.get('q', None):
# Do something here ..
For situations where you only have the request object you can use request.parser_context['kwargs']['your_param']
You have two common ways to do that in case your URL looks like that:
https://domain/method/?a=x&b=y
Version 1:
If a specific key is mandatory you can use:
key_a = request.GET['a']
This will return a value of a if the key exists and an exception if not.
Version 2:
If your keys are optional:
request.GET.get('a')
You can try that without any argument and this will not crash.
So you can wrap it with try: except: and return HttpResponseBadRequest() in example.
This is a simple way to make your code less complex, without using special exceptions handling.
I would like to share a tip that may save you some time.
If you plan to use something like this in your urls.py file:
url(r'^(?P<username>\w+)/$', views.profile_page,),
Which basically means www.example.com/<username>. Be sure to place it at the end of your URL entries, because otherwise, it is prone to cause conflicts with the URL entries that follow below, i.e. accessing one of them will give you the nice error: User matching query does not exist.
I've just experienced it myself; hope it helps!
These queries are currently done in two ways. If you want to access the query parameters (GET) you can query the following:
http://myserver:port/resource/?status=1
request.query_params.get('status', None) => 1
If you want to access the parameters passed by POST, you need to access this way:
request.data.get('role', None)
Accessing the dictionary (QueryDict) with 'get()', you can set a default value. In the cases above, if 'status' or 'role' are not informed, the values ​​are None.
If you don't know the name of params and want to work with them all, you can use request.GET.keys() or dict(request.GET) functions
This is not exactly what you asked for, but this snippet is helpful for managing query_strings in templates.
If you only have access to the view object, then you can get the parameters defined in the URL path this way:
view.kwargs.get('url_param')
If you only have access to the request object, use the following:
request.resolver_match.kwargs.get('url_param')
Tested on Django 3.
views.py
from rest_framework.response import Response
def update_product(request, pk):
return Response({"pk":pk})
pk means primary_key.
urls.py
from products.views import update_product
from django.urls import path
urlpatterns = [
...,
path('update/products/<int:pk>', update_product)
]
You might as well check request.META dictionary to access many useful things like
PATH_INFO, QUERY_STRING
# for example
request.META['QUERY_STRING']
# or to avoid any exceptions provide a fallback
request.META.get('QUERY_STRING', False)
you said that it returns empty query dict
I think you need to tune your url to accept required or optional args or kwargs
Django got you all the power you need with regrex like:
url(r'^project_config/(?P<product>\w+)/$', views.foo),
more about this at django-optional-url-parameters
This is another alternate solution that can be implemented:
In the URL configuration:
urlpatterns = [path('runreport/<str:queryparams>', views.get)]
In the views:
list2 = queryparams.split("&")
url parameters may be captured by request.query_params
It seems more recommended to use request.query_params. For example,
When a URL is like domain/search/?q=haha, you would use request.query_params.get('q', None)
https://www.django-rest-framework.org/api-guide/requests/
"request.query_params is a more correctly named synonym for request.GET.
For clarity inside your code, we recommend using request.query_params instead of the Django's standard request.GET. Doing so will help keep your codebase more correct and obvious - any HTTP method type may include query parameters, not just GET requests."