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How do I fix a reverse error in Django when redirecting?

I am currently working on a website where you can create a shopping list. I am trying to insert items into the shoplist. So things like banana, cake, etc would go into shoplist. I got everything to work. When I create the item, it goes inside the database but when I try to redirect back to the website where I pressed create item, it shows the error
Reverse for 'detail' with keyword arguments '{'pk': 1}' not found. 1 pattern(s) tried: ['shoplist/(?P<item_id>[0-9]+)/$']
Also, when I try to enter my details page, it shows the error
Reverse for 'createitem' with arguments '('',)' not found. 1 pattern(s) tried: ['shoplist/(?P<item_id>[0-9]+)/createitem/$']
I think I did something wrong when making my paths or doing something wrong syntax wise. Nothing I found on the internet is fixing it. Is there a way to fix this problem? Thank you very much!
views.py
def createitem(request, item_id):
if request.method == 'GET':
return render(request, 'shoplist/createitem.html', {'form':ItemForm(), 'id':item_id})
else:
form = ItemForm(request.POST)
itemlist = form.save(commit=False)
itemlist.shoplist = Shoplist.objects.filter(user=request.user, pk=item_id).first()
itemlist.user = request.user
itemlist.save()
return redirect('detail', pk=item_id)
urls.py
from django.contrib import admin
from django.urls import path
from shoplist import views
urlpatterns = [
path('admin/', admin.site.urls),
path('', views.home, name='home'),
#authentication
path('signup/', views.usersignup, name='usersignup'),
path('logout/', views.userlogout, name='userlogout'),
path('login/', views.userlogin, name='userlogin'),
path('create/', views.createlist, name='createlist'),
path('shoplist/', views.currentshoplist, name='currentshoplist'),
path('shoplist/<int:item_id>/', views.detail, name='detail'),
path('shoplist/<int:item_id>/createitem/', views.createitem, name='createitem'),
]
detail.html
{% extends 'shoplist/base.html' %}
{% block content %}
<h2>{{ error }}</h2>
<h1>{{ shopitems }}</h1>
{% for i in item %}
{{i.item}}
{% endfor %}
<form action="{% url 'createitem' item_id %}" method="POST">
{% csrf_token %}
{{ form.as_p }}
<button type="submit">Create Item</button>
</form>
{% endblock %}

You want to redirect to the 'detail' view and the arg required for it is item_id as an int. I think you want redirect('detail', item_id=item_id). However, you probably want to get the created pk from the form... Maybe form.instance.pk? So redirect('detail', item_id=form.instance.pk). It's not clear if that form is for saving the same object type as you're viewing with the 'detail' view.
For the {% url %}, I don't think you can use anything but keyword args. So, {% url 'createitem' item_id=item_id %} if you put item_id into the template context.

Getting NoReverseMatch Error

I have an app that is going to display some information about people in my group. I'm getting a NoReverseMatch error when trying to use the url tag in my index.html. If I do not use the url tag, but specify the root, I do not receive the error.
The error says:
NoReverseMatch at /
Reverse for 'specialist' with arguments '(1,)' and keyword arguments '{}' not found. 1 pattern(s) tried: ['$(?P[0-9]+)/']
Here is are the urls.py files.
From the main wi_tech urls.py:
from django.conf.urls import include, url
from django.contrib import admin
urlpatterns = [
url(r'^$', include('person.urls')),
url(r'^tech/', include('person.urls')),
url(r'^admin/', admin.site.urls),
]
From the 'person' app urls.py:
from django.conf.urls import url
from . import views
app_name = 'person'
urlpatterns = [
url(r'^$', views.IndexView.as_view(), name='index'),
url(r'^(?P<pk>[0-9]+)/$', views.DetailView.as_view(), name='specialist'),
]
My views.py file looks like this:
from django.views import generic
from .models import Specialist
class IndexView(generic.ListView):
template_name = 'person/index.html'
context_object_name = 'person_list'
def get_queryset(self):
"""Return all specialists"""
return Specialist.objects.order_by('id')
class DetailView(generic.DetailView):
model = Specialist
template_name = 'person/detail.html'
And my index.html page looks like this:
{% if person_list %}
<ul>
{% for specialist in person_list %}
<li> {{ specialist }}</li>
{% endfor %}
</ul>
{% else %}
<p>No specialists are available.</p>
{% endif %}
If I change my tag in index.html to this, it works:
<li> {{ specialist }}</li>
Obviously this isn't an ideal situation in case the web root ever changes. I've reviewed a lot of SO questions on this, and nothing seems to match. I think the issue is the "$" in the beginning of the regex, but I don't see where that's coming from.
Specifically, I used this link as a really good reference point, but came up empty looking through my code.
what is NoReverseMatch and how do i fix it
Clearly there's something I'm missing.

Could it be the additional / at the end of the URL?
url(r'^(?P<pk>[0-9]+)/$', views.DetailView.as_view(), name='specialist')
The one after your primary key modifier. When you click the URL (with the (% url ':' model.name %)) what URL comes up in your browser?

I ended up scrapping this implementation, and going with a flatter structure whereby all models, views and templates are in the same application. I have not had this problem in the new design.

Django Error passing URL argument from Template to View: NoReverseMatch Reverse not found. 1 pattern(s) tried

I am trying to pass configure a URL like so:
/details/12345
Template HTML:
<div class="row">
{% if article_list %}
{% for article in article_list %}
<div>
<h2>{{ article.title }}</h2>
<p>{{ article.body }}</p>
<p><a class="btn btn-default" href="{% url 'details' article.id %}" role="button">View details »</a></p>
</div><!--/.col-xs-6.col-lg-4-->
{% endfor %}
{% endif %}
</div><!--/row-->
urls.py (full):
from django.conf import settings
from django.conf.urls import include, url
from django.conf.urls.static import static
from django.contrib import admin
urlpatterns = [
url(r'^admin/', include(admin.site.urls)),
url(r'^$', 'news_readr.views.home', name='home'),
url(r'^details/(?P<article_id>\d+)/$', 'news_readr.views.details', name='details'),
] + static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
if settings.DEBUG:
urlpatterns += static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
views.py:
from django.shortcuts import render
from .models import Article
# Create your views here.
def home(request):
title = "Home"
article_list = Article.objects.all()
for article in article_list:
print(article.id)
context = {
"title": title,
"article_list": article_list,
}
return render(request, "home.html", context)
def details(request, article_id = "1"):
article = Article.objects.get(id=article_id)
return render(request, "details.html", {'article': article})
I am getting an error that says:
NoReverseMatch at /
Reverse for 'details' with arguments '()' and keyword arguments '{}'
not found. 1 pattern(s) tried: ['details/(?P<article_id>\\d+)/$']
I'm one week old at Django, and I think there's something wrong with my URL Named Group config. Please help! TIA!
Update: If I remove the URL config and change it back to:
url(r'^details/$', 'news_readr.views.details', name='details'),
The error changes to:
Reverse for 'details' with arguments '(1,)' and keyword arguments '{}'
not found. 1 pattern(s) tried: ['details/$']
So it seems to be picking up the argument that is passed 1 in this case. So this seems to be an issue with the regular expression. I tried the expression out at Pythex, but even there, the expression doesn't seem to be matching anything.

For the url pattern
url(r'^details/(?P<article_id>\d+)/$', 'news_readr.views.details', name='details'),
The correct way to use the tag is
{% url 'details' article.id %}
This because the details url pattern has a group article_id, so you have to pass this to the tag.
If you have the above url pattern, and {{ article.id}} displays correctly in the template, then the above template tag should not give the error Reverse for 'details' with arguments '()'. That suggests you have not updated the code, or you have not restarted the server after changing code.
If you change the url pattern to
url(r'^details/$', 'news_readr.views.details', name='details')
then you need to remove the article.id from the url tag.
{% url 'details' %}

I guess your pattern is wrong.( not an expert of regex ).
Try this
url(r'^details/((?P<article_id>[0-9]+)/$', 'news_readr.views.details', name='details'),

NoReverseMatch found

I am using django 1.7 & python 3.4
I am trying to implement follow and unfollow a user into my website but i am stuck.
urls.py
url(r'^user/', include('myuserprofile.urls'),),
myuserprofile.urls.py
urlpatterns = patterns('',
url(r'^(?P<slug>[^/]+)/$', 'myuserprofile.views.profile', name='profile'),
url(r'^(?P<slug>[^/]+)/follow/$', 'myuserprofile.views.follow', name='follow'),
url(r'^(?P<slug>[^/]+)/unfollow/$', 'myuserprofile.views.unfollow', name='unfollow'),
views.py
#login_required
def follow(request):
myuser = request.user.id
if request.method == 'POST':
to_user = MyUser.objects.get(id=request.POST['to_user'])
rel, created = Relationship.objects.get_or_create(
from_user=myuser.myuserprofile,
to_user=to_user,
defaults={'status': 'following'}
)
else:
return HttpResponseRedirect(reverse('/'))
if not created:
rel.status = 'following'
rel.save()
and the template portion is like this:
<form action="{% if relationship.status == 'F' %}{% url 'unfollow' %}{% else %}{% url 'follow' %}{% endif %}" method="POST">
Reverse for 'follow' with arguments '()' and keyword arguments '{}' not found. 1 pattern(s) tried: ['user/(?P[^/]+)/follow/$']

You should add the username of the user to follow/unfollow:
{% url 'follow' user_to_follow.username %}
Change the urls.py to:
urlpatterns = patterns('myuserprofile.views',
url(r'^(?P<username>[^/]+)/$', 'profile', name='profile'),
url(r'^(?P<username>[^/]+)/follow/$', 'follow', name='follow'),
url(r'^(?P<username>[^/]+)/unfollow/$', 'unfollow', name='unfollow'),
)
And the signature of the view should accept the username argument:
#login_required
def follow(request, username):
myuser = request.user.id
if request.method == 'POST':
to_user = MyUser.objects.get(username=username)
...

You need to use namespaced URL.
In your case the URL unfollow should be referenced as <app_name>:unfollow.

URL namespaces allow you to uniquely reverse named URL patterns even
if different applications use the same URL names. It’s a good practice
for third-party apps to always use namespaced URLs (as we did in the
tutorial). Similarly, it also allows you to reverse URLs if multiple
instances of an application are deployed. In other words, since
multiple instances of a single application will share named URLs,
namespaces provide a way to tell these named URLs apart
have a look on this Here
you have to use URL namespaces
here is my
polls/urls.py
from django.conf.urls import patterns, url
from . import views
urlpatterns = patterns('',
url(r'^$', views.IndexView.as_view(), name='index'),
url(r'^(?P<pk>\d+)/$', views.DetailView.as_view(), name='detail'),
...
)
so we have use like
{% url 'polls:index' %}

You were missing the slug in your template.
<form action="{% if relationship.status == 'F' %}{% url 'unfollow' %}{% else %}{% url 'follow' %}{% endif %}" method="POST">
It should be
<form action="{% if relationship.status == 'F' %}{% url 'unfollow' user.username %}{% else %}{% url 'follow' user.username %}{% endif %}" method="POST">

Passing an id to a url link - Django

I need to pass a cluster_id in my show.html page, in case the user wishes to halt a cluster created. My urls.py looks like:
from django.conf.urls import url
from django.core.context_processors import csrf
from django.shortcuts import render_to_response
from clusters import views
urlpatterns = [
url(r'^$', views.index, name='index'),
url(r'^register/', views.register, name='register'),
url(r'^show/', views.show, name='show'),
url(r'^login/', views.user_login, name='login'),
url(r'^logout/', views.user_logout, name='logout'),
url(r'^destroy_clusters/', views.destroy_clusters, name='destroy_clusters'),
url(r'^halt_clusters/(?P<cluster_id>\d+)/$', views.halt_clusters, name='halt_clusters'),
url(r'^check_log_status/', views.check_log_status, name='check_log_status'),
url(r'^read_cluster_log/', views.read_cluster_log, name='read_cluster_log'),
]
and in my show.html I have:
{% for cluster in clusters %}
<tr>
<td>{{ cluster.id }}</td>
<td>Halt</td>
<tr>
{% endfor %}
so when I execute the webpage, I have:
NoReverseMatch at /clusters/register/
Reverse for '' with arguments '()' and keyword arguments '{u'cluster_id': 19L}' not found. 0 pattern(s) tried: []
and this is driving me crazy!! Why can't I just pass the id there? I looked this example: Passing an id in Django url but it doesn't seem to work for me. Help?
My Django version is 1.8.dev

In recent Django's you should quote literal URL names in the tag:
{% url "halt_clusters" cluster_id=cluster.id %}
Otherwise Django will look for halt_clusters variable in your context and use its value as the URL name.
Oh, and while you're at it, you don't have to specify the keyword parameter name, so this should work as well:
{% url "halt_clusters" cluster.id %}