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Reverse for 'list-events' not found

Im currently following a Django tutorial to learn views and URLs. I have watched the tutorial over and over and cant see what I am doing wrong.
I receive the error:
Exception Value:
Reverse for 'list-events' not found. 'list-events' is not a valid view function or pattern name.
Views.py
from django.shortcuts import render, redirect
import calendar
from calendar import HTMLCalendar
from datetime import datetime
from .models import Event, Venue
from .forms import VenueForm, EventForm
from django.http import HttpResponseRedirect
# Create your views here.
# all events is listed in the urls.py hence why the function is named all_events
def update_event(request, event_id):
event = Event.objects.get(pk=event_id)
form = EventForm(request.POST, instance=event)
if form.is_valid():
form.save()
return redirect('list-events')
return render(request, 'events/update_event.html',
{'event': event,
'form':form})
def add_event(request):
submitted = False
if request.method == 'POST':
form = EventForm(request.POST)
if form.is_valid():
form.save()
return HttpResponseRedirect('/add_event?submitted=True')
else:
form = EventForm
if 'submitted' in request.GET:
submitted = True
return render(request, 'events/add_event.html', {'form': form, 'submitted': submitted})
def update_venue(request, venue_id):
venue = Venue.objects.get(pk=venue_id)
form = VenueForm(request.POST, instance=venue)
if form.is_valid():
form.save()
return redirect('list-venues')
return render(request, 'events/update_venue.html',
{'venue': venue,
'form': form})
def search_venues(request):
if request.method == "POST":
searched = request.POST['searched']
venues = Venue.objects.filter(name__contains=searched)
return render(request,
'events/search_venues.html',
{'searched': searched,
'venues': venues})
else:
return render(request,
'events/search_venues.html',
{})
def show_venue(request, venue_id):
venue = Venue.objects.get(pk=venue_id)
return render(request, 'events/show_venue.html',
{'venue': venue})
def list_venues(request):
venue_list = Venue.objects.all()
return render(request, 'events/venue.html',
{'venue_list': venue_list})
URLS.py
from django.urls import path
from . import views
urlpatterns = [
path('', views.home, name="home"),
path('<int:year>/<str:month>/', views.home, name="home"),
path('events', views.all_events, name='list_events'),
path('add_venue', views.add_venue, name='add-venue'),
path('list_venues', views.list_venues, name='list-venues'),
path('show_venue/<venue_id>', views.show_venue, name='show-venue'),
path('search_venues', views.search_venues, name='search-venues'),
path('update_venue/<venue_id>', views.update_venue, name='update-venue'),
path('add_event', views.add_event, name='add-event'),
path('update_event/<event_id>', views.update_event, name='update-event'),
event_list.html:
{% extends 'events/base.html' %}
{% block content %}
<h1>Event </h1>
<br />
{% for event in event_list %}
<div class="card">
<div class="card-header">
{{Event}}
</div>
<div class="card-body">
<h5 class="card-title">Venue: {{ event.venue }}</h5>
<p class="card-text">
<ul>
<li>Date: {{ event.event_date }}</li>
<li>Event Venue: {{ event.venue.web }}</li>
<li>Manager: {{ event.manager }}</li>
<li>Desc: {{ event.description }}</li>
<li>Attendees:<br />
{% for user in event.attendees.all %}
{{ user }}<br/>
{% endfor %}
</li>
</ul>
</p>
</div>
<div class="card-footer text-muted">
Update Event
</div>
</div>
<br /><br />
{% endfor %}
{% endblock %}

You have defined your url in the "urls.py" file with the name of "list_events" (note the underscore). In the views you have used it as "list-events" (note the hyphen).
You can fix that by following one of these options:
1.You can change that in the views (by using underscore instead of hyphen):
return redirect('list_events')
2.Or changing it in the url (by using hyphen instead of underscore):
path('events', views.all_events, name='list-events'),

python crash course 19-1 edit posts not working

This is the error I get when clicking on Edit post under any one of the posts. Would appreciate any help as all this django stuff is confusing me but trying my best to learn. My new post function works and clicking blog/posts to go to the overview page for the blog or to look at all the posts works as well.
NoReverseMatch at /edit_post/1/
Reverse for 'posts' with arguments '(1,)' not found. 1 pattern(s) tried: ['posts/$']
Error during template rendering
In template C:\Users\seng\Desktop\Python projects\c19\nineteen_one\blogs\templates\blogs\base.html, error at line 0
urls.py
"""Defines url paterns for blogs"""
from django.urls import path
from . import views
app_name = 'blogs'
urlpatterns =[
#Home page
path('', views.index, name='index'),
# Page that shows all posts/
path('posts/', views.posts, name='posts'),
#Page for adding a new blogpost
path('new_post/', views.new_post, name='new_post'),
#Page for editing a post
#maybe remove the id?
path('edit_post/<int:post_id>/', views.edit_post, name='edit_post'),
]
views.py
from django.shortcuts import render, redirect
from .models import BlogPost
from .forms import BlogPostForm
# Create your views here.
def index(request):
"""The home page for blogs"""
return render(request, 'blogs/index.html')
def posts(request):
"""Show all blogposts"""
posts = BlogPost.objects.order_by('date_added')
context = {'posts': posts}
return render(request, 'blogs/posts.html', context)
def new_post(request):
"""Add a new blogpost"""
if request.method != 'POST':
#No data submitted; create a blank form.
form = BlogPostForm()
else:
#POST data submitted, process data
form = BlogPostForm(data=request.POST)
if form.is_valid():
form.save()
return redirect('blogs:posts')
#Display a blank or invalid form
context = {'form': form}
return render(request, 'blogs/new_post.html', context)
def edit_post(request, post_id):
"""Edit existing post"""
post = BlogPost.objects.get(id=post_id)
if request.method != "POST":
#Initial request, pre-fill form with the current post
form = BlogPostForm(instance=post)
else:
#Post data submitted, process data
form = BlogPostForm(instance=post, data=request.POST)
if form.is_valid():
form.save()
return redirect('blogs:posts', post_id=post.id)
context = {'post':post, 'form':form}
return render(request, 'blogs/edit_post.html', context)
forms.py
from django import forms
from .models import BlogPost
class BlogPostForm(forms.ModelForm):
class Meta:
model = BlogPost
fields = ['text', 'title']
labels = {'text':'This is the text box', 'title' :"Title here"}
edit_post.html
{% extends "blogs/base.html" %}
{% block content %}
<p>{{ post }}</p>
<p>Edit post:</p>
<form action="{% url 'blogs:edit_post' post.id %}" method='post'>
{% csrf_token %}
{{ form.as_p }}
<button name="submit">Save changes</button>
</form>
{% endblock content %}
posts.html
{% extends "blogs/base.html" %}
{% block content %}
<p>Posts</p>
<ul>
{% for post in posts %}
<li>
<p>{{ post }}</p>
<p>
Edit post
</p>
</li>
{% empty %}
<li>No posts have been added yet.</li>
{% endfor %}
</ul>
Add a new post
{% endblock content %}
new_post.html
{% extends "blogs/base.html" %}
{% block content %}
<p>Add a new post:</p>
<form action="{% url 'blogs:new_post' %}" method='post'>
{% csrf_token %}
{{ form.as_p }}
<button name="submit">Add post</button>
</form>
{% endblock content %}

The issue is with this line in edit_post.html:
<p>{{ post }}</p>
If you are editing the post with id 1, then this link is to the url /posts/1. But that has no match in your urls.py file.
Either you need to remove the post.id parameter from the link, or create a view and a corresponding path in urls.py for this link.

Django NoReverseMatch Error during Template Rendering

I am setting up a simple blog site with Django, and run into this error when trying to link to a page that allows users to edit existing blog posts.
Reverse for 'edit_post' with arguments '('',)' not found. 1 pattern(s) tried: ['edit_post/(?P<title_id>[0-9]+)/$']
If I understand this error correctly, it means that Django can't find a urlpattern that matches the url being requested. To my eyes I have the urlpattern set up correctly, but I still get the error.
The link in question appears on the text.html template, which is the template that displays the text of a particular blog post.
Here is the relevant code:
urls.py
"""Defines URL patterns for blogs."""
from django.urls import path
from . import views
app_name = 'blogs'
urlpatterns = [
# Home page, shows all posts in chronological order.
path('', views.index, name='index'),
# A page to show the text of a specific post.
path('text/<int:title_id>/', views.text, name='text'),
# Page for adding a new post.
path('new_post/', views.new_post, name='new_post'),
# Page for editing a post.
path('edit_post/<int:title_id>/', views.edit_post, name='edit_post'),
]
views.py
from django.shortcuts import render, redirect
from .models import BlogPost
from .forms import BlogPostForm
def index(request):
"""The home page for blogs, shows all posts."""
titles = BlogPost.objects.order_by('date_added')
context = {'titles': titles}
return render(request, 'blogs/index.html', context)
def text(request, title_id):
"""Show a single post title and its text."""
title = BlogPost.objects.get(id=title_id)
text = title.text
context = {'title': title, 'text': text}
return render(request, 'blogs/text.html', context)
def new_post(request):
"""Add a new post."""
if request.method != 'POST':
# No data submitted; create a new form.
form = BlogPostForm()
else:
# POST data submitted; process data.
form = BlogPostForm(data=request.POST)
if form.is_valid():
new_post = form.save(commit=False)
new_post.save()
return redirect('blogs:index')
# Display a blank or invalid form.
context = {'form': form}
return render(request, 'blogs/new_post.html', context)
def edit_post(request, title_id):
"""Edit an existing post."""
post = BlogPost.objects.get(id=title_id)
if request.method != 'POST':
# Initial request: pre-fill form with the current post.
form = BlogPostForm(instance=post)
else:
# Post data submitted; process data.
form = BlogPostForm(instance=post, data=request.POST)
if form.is_valid():
form.save()
return redirect('blogs:index')
context = {'post': post, 'form': form}
return render(request, 'blogs/edit_post.html', context)
index.html (this is the homepage for the blog)
{% extends "blogs/base.html" %}
{% block content %}
<p>Blog is a generic site for a blogger to post content for their audience.</p>
<p>Posts</p>
<ul>
{% for title in titles %}
<li>
{{ title }}
</li>
{% empty %}
<li>No posts have been added yet.</li>
{% endfor %}
</ul>
Create a new post
{% endblock content %}
text.html (this page displays the text content of a particular post, and also the link to edit the post)
{% extends "blogs/base.html" %}
{% block content %}
<p>Title: {{ title }}</p>
<p>{{ text }}</p>
Edit post
{% endblock content %}
edit_post.html (this page should display the existing post and allow it to be edited)
{% extends "blogs/base.html" %}
{% block content %}
<p>Edit post:</p>
<p>Title:</p>
<form action="{% url 'blogs:edit_post' title.id %}" method='post'>
{% csrf_token %}
{{ form.as_p }}
<button name="submit">Save changes</button>
</form>
{% endblock content %}
How the edit_post function in views.py should work (in theory) is to create an instance based upon the post's title id, and then allowing the user to edit it and save changes.
I'm not sure where I'm going wrong here and any suggestions are greatly appreciated.

The name of the post object you pass to the template, is not title, but post:
{% extends "blogs/base.html" %}
{% block content %}
<p>Edit post:</p>
<p>Title:</p>
<form action="{% url 'blogs:edit_post' post.pk %}" method='post'>
{% csrf_token %}
{{ form.as_p }}
<button name="submit">Save changes</button>
</form>
{% endblock content %}
If you use title.id, it will not find that variable, and thus this will be resolved to the empty string. If you use post.id, or post.pk, it will resolve to the .id field, or primary key of the post object.

Django: How to have multiple "add another field" buttons in a form

I'm new to django and I'm having a lot of trouble with forms.
I'm making a calculation-based tool and I need to be able to have an arbitrary number of inputs.
As a really basic example, let's say I want to make a calculator that will sum and subtract any number of inputs. Each number to be added or subtracted is in its own number field. Both the list of "adding" fields and the list of "subtracting" fields has its own "add another field" button.
For starters, here's something that adds two inputs (since I can't figure out how to implement even 1 "add another field button" or understand the answer to it).
views.py
from __future__ import unicode_literals
from django.http import HttpResponse, HttpResponseRedirect
from django.shortcuts import render
from django.views.decorators.csrf import csrf_exempt
from .forms import AddForm
def _from_str(s):
try:
s = int(s)
except ValueError:
try:
s = float(s)
except ValueError:
pass
return s
#csrf_exempt
def web_adder(request):
if request.method == 'POST':
form = AddForm(request.POST)
# form = MyForm(request.POST, extra=request.POST.get('extra_field_count'))
if form.is_valid():
return web_adder_out(request, _from_str(form.cleaned_data['addend0']), _from_str(form.cleaned_data['addend1']))
else:
form = AddForm()
# form = MyForm()
return render(request, 'addercontent.html', {'form': form})
def web_adder_out(request, a, b):
return render(request, 'addercontentout.html', {'content':[a + b]})
forms.py
from django import forms
class AddForm(forms.Form):
addend0 = forms.CharField(label='first addend', max_length=100)
addend1 = forms.CharField(label='second addend', max_length=100)
addercontent.html
{% block content %}
<p>This is a web adder</p>
<form action="" method="post">
{% csrf_token %}
{{ form.as_p }}
<button type="submit" class="btn btn-default">Enter</button>
</form>
{% endblock %}
addercontentout.html
{% block content %}
{% for c in content%}
Result: {{c}}
<br>
Return
{% endfor %}
{% endblock %}

Don't use Django for the field generation. I would do all of it via HTML. Run your setup that you currently have, and you should be able to look at the page source to see how the inputs are structured. Then you can manually write the form in HTML, with JavaScript adding fields in as needed.

Something like this? (not tested, I haven't implement add button)
forms.py
class CalcForm(forms.Form)
first = forms.IntegerField()
second = forms.IntegerField()
def add(self):
first = self.cleaned_data['first']
second = self.cleaned_data['second']
return first + second
views.py
def index(request):
if request.method == "POST":
form = CalcForm(request.POST)
if form.is_valid():
result = form.add()
return render(request, 'your_result_template.html', {'result': result})
else:
form = CalcForm()
return render(request, 'your_template.html', {'form': form})
your_template.html
{% block content %}
<p>This is a web adder</p>
<form method="post">
{% csrf_token %}
{{ form.as_p }}
<button type="submit" class="btn btn-default">Enter</button>
</form>
{% endblock %}
your_result_template.html
{% block content %}
<p>Sum:</p>
<h2>{{ result }}</h2>
{% endblock %}
Edit: For field generation you may need javascript.
I don't know why you want to use django for this kind of app.

Django : CSRF verification failed even after adding {% csrf_token %}

views.py:
def index(request):
return render_to_response('index.html', {})
def photos(request, artist):
if not artist:
return render_to_response('photos.html', {'error' : 'no artist supplied'})
photos = get_photos_for_artist(artist)
if not photos:
logging.error('Issue while getting photos for artist')
return render_to_response('photos.html', {'error': 'no matching artist found'})
return render_to_response('photos.html', {'photos': photos})
Index.html:
<html>
<head>
<title>find artist photos </title>
</head>
<body>
{% block error %} {% endblock %}
<form action="/photos" method="POST">
{% csrf_token %}
<label for="artist">Artist : </label>
<input type="text" name="artist">
<input type="submit" value="Search">
</form>
{% block content %}{% endblock %}
</body>
</html>
photos.html:
{% extends 'index.html' %}
{% block error %}
{% if error %}
<p> {{ error}} </p>
{% endif %}
{% endblock %}
{% block content %}
{% if photos %}
{% for photo in photos %}
{{ photo }}
{% endfor %}
{% endif %}
{% endblock%}
url.py:
urlpatterns = patterns('',
(r'', index),
(r'^time/$', current_datetime),
(r'^photos/(\w+)$', photos)
)
I even tried by adding {% csrf_token %}, but no luck
Thank you
UPDATE
I see these in the logs
UserWarning: A {% csrf_token %} was used in a template, but the context did not provide the value. This is usually caused by not using RequestContext.
warnings.warn("A {% csrf_token %} was used in a template, but the context did not provide the value. This is usually caused by not using RequestContext.")
This came after adding context_instance=RequestContext(request) **to render_to_response()**

add context_instance=RequestContext(request) to every view that you will use a form inside it:
return render_to_response('index.html', {}, context_instance=RequestContext(request) )
return render_to_response('photos.html', {'photos': photos}, context_instance=RequestContext(request) )

Supposing you are using a fairly recent version of Django (1.3/1.4/dev) you should follow these steps :
In settings.py, Add the middleware django.middleware.csrf.CsrfViewMiddleware to the
MIDDLEWARE_CLASSES list.
In your template, use the {% crsf_token %} in the form.
In your view, ensure that the django.core.context_processors.csrf context processor is used either by :
use RequestContext from django.template
directly import the csrf processor from from django.core.context_processors
Examples
from django.template import RequestContext
from django.shortcuts import render_to_response
def my_view(request):
return render_to_response('my_template.html', {}, context_instance=RequestContext(request))
or
from django.core.context_processors import csrf
from django.shortcuts import render_to_response
def my_view(request):
c = {csrf(request)}
return render_to_response('my_template.html', c)
References
csrf in Django 1.3 or csrf in Django 1.4
RequestContext in Django 1.3 or RequestContext in Django 1.4
(exhaustive post for posterity and future viewers)

A number of things to troubleshoot here:
Please load your "index" page in a web browser, do "View Source", and check if the {% csrf_token %} is being expanded. It should be replaced with an <input> tag. If that's not happening, then you have problems with your index page. If it is being replaced correctly, then you have problems with your photos page.
The POST URL in index.html doesn't match any of the patterns in urls.py. Your urls.py seems to expect the search term to be part of the URL, but it's not - you're sending it as a HTTP POST parameter. You need to access it via request.POST.

Check in the settings, if you have this middleware:
'django.middleware.csrf.CsrfViewMiddleware'
https://docs.djangoproject.com/en/dev/ref/contrib/csrf/

You may need to explicitly pass in a RequestContext instance when you use render_to_response in order to get the CSRF values for that template tag.
http://lincolnloop.com/blog/2008/may/10/getting-requestcontext-your-templates/

Try using the #csrf_protect decorator:
from django.views.decorators.csrf import csrf_protect
from django.shortcuts import render_to_response
#csrf_protect
def photos(request,artist):
if not artist:
return render_to_response('photos.html', {'error' : 'no artist supplied'})
photos = get_photos_for_artist(artist)
if not photos:
logging.error('Issue while getting photos for artist')
return render_to_response('photos.html', {'error': 'no matching artist found'})
return render_to_response('photos.html', {'photos': photos})

This worked for me:
{% csrf_token %}
In the template, there is a {% csrf_token %} template tag inside each POST form that targets an internal URL.
In views.py:
from django.template import RequestContext
...
...
...
return render_to_response("home.html", {}, context_instance=RequestContext(request))