How to pass url parameter to reverse_lazy in Django urls.py

Question

Consider that I have 1 resource and 2 urls (let's say new one and old one) connected to that resourse. So, i want to setup HTTP redirection for one of urls.

In myapp/urls.py I have:

urlpatterns = patterns('',
    url(r'^(?P<param>\d+)/resource$', 
                      'myapp.views.resource', 
                       name='resource-view'
    ),
)

In mycoolapp/urls.py I want to specify:

from django.views.generic.simple import redirect_to
from django.core.urlresolvers import reverse_lazy

urlpatterns = patterns('',
    url(r'^coolresource/(?P<param>\d+)/$', 
                       redirect_to, 
                       {
                          'url': reverse_lazy('resourse-view', 
                                         kwargs={'param': <???>}, 
                                         current_app='myapp'
                                 ),
                       }
   ),
)

The question is how to pass <param> to the reverse_lazy kwargs (so, what to put instead of <???> in the example above)?

score 31 · Answer 1 · answered Jan 22 '13 at 23:54

I wouldn't do this directly in the urls.py, I'd instead use the class-based RedirectView to calculate the view to redirect to:

from django.views.generic.base import RedirectView
from django.core.urlresolvers import reverse_lazy

class RedirectSomewhere(RedirectView):
    def get_redirect_url(self, param):
        return reverse_lazy('resource-view',
                            kwargs={'param': param},
                            current_app='myapp')

Then, in your urls.py you can do this:

urlpatterns = patterns('',
    url(r'^coolresource/(?P<param>\d+)/$', 
        RedirectSomewhere.as_view()),
)

scroll down to the solution using `pattern_name`, that's the correct solution for Django 1.6 and later — Tim Tisdall, Nov 04 '21 at 12:26

score 7 · Answer 2 · edited Dec 15 '15 at 11:35

Redirect View is great if you are using a hard coded url, it replaced redirect_to which is now deprecated. I don't think you can use it when redirecting and reversing from urls.py. Here is my solution, x is the response object in this case:

from django.core.urlresolvers import reverse
from django.http import HttpResponseRedirect
urlpatterns = patterns('',
    ....
    url(r'^coolresource/(?P<param>\d+)/$',
                         lambda x, param: HttpResponseRedirect(
                             reverse('myapp.views.resource', args=[param])
                         ),
                         name='resource-view-redirect'),
    ....
)

You can still use the name of the url pattern instead of a hard coded url with this solution. The location_id parameter from the url is passed down to the lambda function.

This is the cleverest solution here – Jamie S Sep 06 '15 at 14:01 — Jamie S, Sep 06 '15 at 14:01

score 6 · Answer 3 · answered Jul 09 '15 at 16:44

6

As of Django 1.6 you can do this (Documentation):

...
from django.views.generic.base import RedirectView

urlpatterns = patterns('',
    url(r'^coolresource/(?P<param>\d+)/$', 
         RedirectView.as_view(pattern_name='resource-view'),
    ),
)

answered Jul 09 '15 at 16:44

Pykler

14,565
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How does this work if you want to pass args or kwargs to the pattern? – Flimm Jan 05 '17 at 11:14
@Flimm this answer might help http://stackoverflow.com/a/12150035/742390 – Pykler Jan 05 '17 at 15:14

gakhov · Accepted Answer · 2012-10-14T15:38:34.673

3

One of the possible solutions of the general problem is to use hard-coded url pattern instead of reverse_lazy (documentation)

url(r'^coolresource/(?P<param>\d+)/$', 
                       redirect_to, 
                       {'url': '/%(param)s/resource'}
),

But, I don't like it so much, since it makes me harder after to do possible changes in urls.

edited Oct 14 '12 at 15:38

answered Mar 27 '12 at 12:39

gakhov

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documentation link? page not found – grgizem Oct 14 '12 at 11:17
@grgizem the post created half a year ago .. sorry. Anyway, i've updated the link – gakhov Oct 15 '12 at 07:58

score 1 · Answer 5 · answered Mar 26 '12 at 20:28

1

You can't know or get what the value is until the view is called, so calculate url inside it.

answered Mar 26 '12 at 20:28

Ignacio Vazquez-Abrams

776,304
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score 0 · Answer 6 · answered Mar 26 '12 at 20:47

0

Django's regex matching method for urls allows one to define and assign variables:

(?P<variable_name>...) defines variable_name depending on the uri being called; so what you need to put is: param instead of <???>

answered Mar 26 '12 at 20:47

Umur Kontacı

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How to pass url parameter to reverse_lazy in Django urls.py

6 Answers6