NoReverseMatch in Django for username pass to view - django

Question

I'm working on a basic Django app (just learning, this is my third small project), and I'm trying to add links to allow a list of every post a user has made. I've got the URLS being created OK (domain/posts/username), and I want this to link to a view (that I've already created, and which works when the parameters I want to pass are hard-coded to a single value), passing the positional arguments to the view. However, I'm running aground on the RegEx / Urls part of things. I think this is the relevant info:
urls.py:
urlpatterns = [
url(r'^create/', views.create, name='create'),
url(r'^(?P<pk>[0-9]+)/upvote', views.upvote, name='upvote'),
url(r'^(?P<pk>[0-9]+)/downvote' , views.downvote, name='downvote'),
url(r'^userposts/(?P<user>[.]+)', views.userposts, name='userposts')
views.py
def userposts(request,user):
posts = models.Post.objects.filter(url__contains=user)
return render(request, 'posts/userposts.html', {'posts': posts})
home.html
a href="{{ post.url}}">{{ post.title }}</a><br/>{{ post.pub_date_pretty }} by
{{ post.author.username }}</td>
With the (?P[.]+) part of the last url line removed, the page will render OK, but the links don't work (as there's no user parameter being passed). With the regex present (not only this one, but the many others I've tried), I get a NoReverseMatch error:
NoReverseMatch at /
Reverse for 'userposts' with no arguments not found. 1 pattern(s) tried: ['posts/userposts/(?P<user>[.]+)']
Request Method: GET
Request URL: http://127.0.0.1:8000/
Django Version: 1.11
Exception Type: NoReverseMatch
Exception Value:
Reverse for 'userposts' with no arguments not found. 1 pattern(s)
tried: ['posts/userposts/(?P<user>[.]+)']
Exception Location: /usr/local/lib/python3.5/dist-
packages/django/urls/resolvers.py in _reverse_with_prefix, line 497
Python Executable: /usr/bin/python3
Python Version: 3.5.2
Python Path:
['/home/darren/redditclone/redditclone',
'/usr/lib/python35.zip',
'/usr/lib/python3.5',
'/usr/lib/python3.5/plat-x86_64-linux-gnu',
'/usr/lib/python3.5/lib-dynload',
'/home/darren/.local/lib/python3.5/site-packages',
'/usr/local/lib/python3.5/dist-packages',
'/usr/lib/python3/dist-packages']
Server time: Thu, 18 May 2017 18:21:11 +0000

Answer 1

Your userposts is defined like
url(r'^userposts/(?P<user>[.]+)', views.userposts, name='userposts')
which means it requires a user argument to resolve.
To pass such an argument, you'd do
{% url 'posts:userposts' user_goes_here %}
Try this instead
{{ post.author.username }}