We Keep Coding

Reverse for 'edit_blog_post' with arguments '('',)' not found

I am trying to create a way to edit individual blog posts from their individual html. Here are the relevant files and trace back. I am somewhat understanding that the issue lies in blog_post.id being due to the fact that blog_post has not carried over from the for loop on blog_posts.html. I have read up on others having this issue and they all structured their pages to have the edit button being inside the original for loop, which makes sense in hindsight. BUT now that I have run into this issue, I'm determined to understand how I can solve it without going back and restructuring my pages to align with the others I saw.
urls.py
from django.urls import path
from . import views
app_name = 'blogs'
urlpatterns = [
# Home page
path('', views.index, name='index'),
path('blog_posts/', views.blog_posts, name='blog_posts'),
path('blog_posts/<int:blog_post_id>/', views.blog_post, name='blog_post'),
path('new_blog_post/', views.new_blog_post, name='new_blog_post'),
path('edit_blog_post/<int:blog_post_id>/', views.edit_blog_post, name='edit_blog_post'),
]
views.py
from .models import BlogPost
from .forms import BlogPostForm
def index(request):
"""Home page for Blog."""
return render(request, 'blogs/index.html')
def blog_posts(request):
"""Show all Blog Posts."""
blog_posts = BlogPost.objects.order_by('date_added')
context = {'blog_posts': blog_posts}
return render(request, 'blogs/blog_posts.html', context)
def blog_post(request, blog_post_id):
"""Show details of an individual blog post."""
blog_post = BlogPost.objects.get(id=blog_post_id)
title = blog_post.title
id = blog_post_id
date = blog_post.date_added
text = blog_post.text
context = {'title': title, 'text': text, 'date': date}
return render(request, 'blogs/blog_post.html', context)
def new_blog_post(request):
"""Add a new blog post"""
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:blog_posts')
# Display a blank or invalid form.
context = {'form': form}
return render(request, 'blogs/new_blog_post.html', context)
def edit_blog_post(request, blog_post_id):
"""Edit an existing blog post's title or text."""
blog_post = BlogPost.objects.get(id=blog_post_id)
if request.method != 'POST':
# Initial request, prefill with the current data.
form = BlogPostForm(instance=blog_post)
else:
# POST data submitted; process new data.
form = BlogPostForm(instance=blog_post, data=request.POST)
if form.is_valid():
form.save()
return redirect('blogs:blog_post', blog_post_id=blog_post.id)
context = {'blog_post': blog_post, 'form': form}
return render(request, 'blogs/edit_blog_post.html', context)
models.py
from django.db import models
class BlogPost(models.Model):
"""A post the user is posting on their blog."""
title = models.CharField(max_length=200)
text = models.TextField()
date_added = models.DateTimeField(auto_now_add=True)
def __str__(self):
"""Return a string representation of the model"""
return f"{self.title.title()}"
blog_posts.html
{% extends 'blogs/base.html' %}
{% block content %}
<p>Blog Posts</p>
<ul>
{% for blog_post in blog_posts %}
<li>
{{ blog_post }}
</li>
{% empty %}
<li>No posts have been made yet.</li>
{% endfor %}
</ul>
Add a new blog post
{% endblock content %}
blog_post.html
{% extends 'blogs/base.html' %}
{% block content %}
<p>Blog Post: {{ title }}</p>
<p>Entry:</p>
<p>{{ text }}</p>
<p>{{ date }}</p>
<p>
Edit Blog Post
</p>
{% endblock content %}
edit_blog_post.html
{% extends "blogs/base.html" %}
{% block content %}
<p>
{{ blog_post }}
</p>
<p>Edit Blog Post</p>
<form action="{% url 'blogs:edit_blog_post' blog_post.id %}" method='post'>
{% csrf_token %}
{{ form.as_p }}
<button name="submit">Save Changes</button>
</form>
{% endblock content %}
Reverse for 'edit_blog_post' with arguments '('',)' not found. 1 pattern(s) tried: ['edit_blog_post/(?P<blog_post_id>[0-9]+)/\Z']
3 {% block content %}
4
5 <p>Blog Post: {{ title }}</p>
6
7 <p>Entry:</p>
8
9 <p>{{ text }}</p>
10 <p>{{ date }}</p>
11
12 <p>
13 Edit Blog Post
14 </p>
15
16 {% endblock content %}

If I've read the question correctly, You're getting the error becuase you are not providing the necessary ID to the URL construction part of your template.
You're separating out the elements (date, content etc) to send to the template, but not passing the ID at the same time. You could send the ID in as a separate context variable, but that's extra typing for no real reward.
It's easiest to pass in the post itself via context and refer to its attributes in the template - I think it makes it easier to read also. That way the ID is there when you need to contruct the edit link, and if you change the model to possess extra fields, you don't need to convert and add to the context as the whole post is already there.
views.py
def blog_post(request, blog_post_id):
"""Show details of an individual blog post."""
blog_post = BlogPost.objects.get(id=blog_post_id) #this is all we need
context = {"blog_post_context": blog_post}
return render(request, 'blogs/blog_post.html', context)
blog_post.html
{% extends 'blogs/base.html' %}
{% block content %}
<p>Blog Post: {{ blog_post_context.title }}</p>
<p>Entry:</p>
<p>{{ blog_post_context.text }}</p>
<p>{{ blog_post_context.date }}</p>
<p>
Edit Blog Post
</p>
{% endblock content %}
If that all works, look into using get_object_or_404 rather than Post.objects.get for some additional robustness.

I assume you got the error when you try visiting the blog_post.html page. If I'm correct, then here's an approach you could take...
In your views.py
def blog_post(request, blog_post_id):
"""Show details of an individual blog post."""
# blog_post = BlogPost.objects.get(id=blog_post_id)
blog_post = get_object_or_404(id=blog_post_id) # Recommended
# Commented lines below are somewhat not necessary...
# title = blog_post.title
# id = blog_post_id
# date = blog_post.date_added
# text = blog_post.text
context = {'blog_post': blog_post}
return render(request, 'blogs/blog_post.html', context)
edit_blog_post.html is expecting an object called blog_post to be able to access the blog_post.id for {% url 'blogs:edit_blog_post' blog_post.id %}.
Now within the edit_blog_post.html file.
{% block content %}
<p>Blog Post: {{ blog_post.title }}</p>
<p>Entry:</p>
<p>{{ blog_post.text }}</p>
<p>{{ blog_post.date_added }}</p>
<p>
Edit Blog Post
</p>
{% endblock content %}

How do you get queryset objects related to queryset passed to templates in Django

I have these two models and as you can see they have a relationship.
class Post(models.Model):
text = models.TextField()
class PostImage(models.Model):
post = models.ForeignKey(Post, default=None, on_delete=models.CASCADE)
image = models.FileField(upload_to = 'media/',blank=True, null=True)
As far as I understand if I query posts and push them to a template and post, I would expect to use something like this in my templates to retrieve the images URL attached to the posts but it doesn't seem to work.
{% for post in posts %}
{% for post_image in post.post_image_set.all %}
{{post_image.image.url}}
{% endfor %}
{% endfor %}
What am I doing wrong?
Here is my views.py file.
views.py
# Create your views here.
def index(request):
posts=Post.objects.filter(approved=True).order_by('-published_date')
context = {"posts":posts}
return render(request, 'post/home.html',context)

The default related name for a foreign key relational is the name of the model (PostImage) but in your template for loop you called it post_image Following relationships “backward”
change
{% for post_image in post.post_image_set.all %}
into
{% for post_image in post.postimage_set.all %}
Template code (with change)
{% for post in posts %}
{% for post_image in post.postimage_set.all %}
{{post_image.image.url}}
{% endfor %}
{% endfor %}

Posts not showing author who wrote it in Django

Basically, I'm writing an app in which people can make blog and image posts. So far, I've completed users to be able to write text posts. However, when I try to create a post, it returns "By: None" when it should be returning "By: shrey". In this case, Bob is the author. Here's an image:
Here's an image for the post creation view:
Theoretically, when I enter a post it should say who it was written by.
Here's the template for the create post:
{% extends "social/base.html" %}
{% load crispy_forms_tags %}
{% block content4 %}
<h1>Make Your Post</h1>
<p>Write a post / Share an image</p>
<br>
<div class="container">
<form method="post">
{% csrf_token %}
{{form|crispy}}
<button type="submit" name="button">Make Post</button>
</form>
</div>
{% endblock content4 %}
Here's the function for the create post view:
class PostCreateView(CreateView):
model = Posts
fields = ['post_title', 'post_text_content']
def form_valid(self, form):
form.instance.author = self.request.user
print(self.request.user)
return super().form_valid(form)
Thank you in advance.
EDIT: Home Page Template (template which displays the posts):
{% extends "social/base.html" %}
{% block content %}
<h1>Your Feed</h1>
<p>This is your feed. Here, you'll see posts from people you follow.</p>
{% if user.is_authenticated %}
<p>You are logged in as {{user.username}}. This is your feed.</p>
{% else %}
<p>You are not logged in. This is a random feed.</p>
{% endif %}
{% for post in posts %}
<h1>{{ post.post_title }}</h1>
<p>By {{ post.post_author }} on <i>{{ post.post_date }}</i></p>
<p>{{ post.post_text_content }}</p>
{% endfor %}
Click here to make a post.
<br>
Click here to logout.
<br>
Click here to login.
<br>
Click here to sign up and make an account.
<!--<p>Want to post something? Enter your info here: </p> -->
{% endblock content %}
Posts Model:
class Posts(models.Model):
post_title = models.CharField(max_length = 40, help_text = 'Enter post title')
post_text_content = models.TextField(max_length = 1000)
post_author = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
post_date = models.DateField(auto_now = True, auto_now_add = False)
#Make optional Image Field
class Meta:
ordering = ['post_title', 'post_author', 'post_date', 'post_text_content']
def __str__(self):
return self.post_title
def get_absolute_url(self):
return reverse('social-home')

The name of the field is post_author, not author, hence you should set post_author:
class PostCreateView(CreateView):
model = Posts
fields = ['post_title', 'post_text_content']
def form_valid(self, form):
form.instance.post_author = self.request.user
return super().form_valid(form)
That being said, normally in Django one does not prefixes the model fields with the name of the model. One reason not to do that is that you can define abstract models where you define the field once, and then use inheritance to add the field to other models.

How to access model.field in template? django

I started learning django few days ago and trying to build my first blog.
My problem is that I decided to add an extra field for my categories (subheading), which I want to be in my template, but can't understand how to do it.
my models.py
from django.db import models
class Category(models.Model):
name = models.CharField(max_length=20)
subheading = models.CharField(max_length=160)
def __str__(self):
return self.name
class Post(models.Model):
title = models.CharField(max_length=255)
body = models.TextField()
link = models.TextField()
categories = models.ManyToManyField("Category", related_name="posts")
def __str__(self):
return self.title
views.py
from django.shortcuts import render
from blog.models import Post, Category
def blog_category(request, category):
posts = Post.objects.filter(
categories__name__contains=category
).order_by(
'title'
)
context = {
"category": category,
"posts": posts
}
return render(request, "blog_category.html", context)
The only way category.name or category.subheading are displayed in template (by the teacher) is inside {% for post in posts %} {% endfor %}:
{% for post in posts %}
{% for category in post.categories.all %}
{{ category.subheading }}
{% endfor %}
{% endfor %}
In this case, if there are 10 posts on category page, subheading repeats 10 times. I only need to print 1 to describe category.
Is there a way to call category.subheading outside of {% for post in posts %} ? Or somehow to print only one result.
p.s. sorry for my primitive English level.

You can do this with a Prefetch object [Django-doc]:
from django.db.models import Prefetch
def blog_category(request, category):
posts = Post.objects.filter(
categories__name__contains=category
).prefetch_related(
Prefetch(
'categories',
Category.objects.filter(name__contains=category)
to_attr='relevant_categories'
)
).order_by(
'title'
)
# …
In your template, you can then render this with:
{% for post in posts %}
{% for category in post.relevant_categories %}
{{ category.subheading }}
{% endfor %}
{% endfor %}

Not sure to understand what you want to do but you can search and access to Category elements by doing something like that:
categories=Category.objects.filter(name='NameYouWanttoSearch').values_list('subheading')

can add a model manager to the categories , take single instance and call it in templates instead of all.
class CategoryManager(models.Manager):
def single_category(self):
return self.get_queryset()[:1]
class Category(models.Model):
name = models.CharField(max_length=20)
subheading = models.CharField(max_length=160)
objects = CategoryManager()
def __str__(self):
return self.name
and in templates
{% for post in posts %}
{% for category in post.categories.single_category %}
{{ category.subheading }}
{% endfor %}
{% endfor %}

How to acces the the django ManyToMany Field in django Template

I have set of attributes in my Models from which one of the attribute is of Type ManyToMany Field. I am able to access all the Attributes in Template instead one which is ManyToMany Field.
I have tried following in my template
{% for post in all_posts %}
{{ post.likes }}
{% endfor %}
models.py
class Posts(models.Model):
title = models.CharField(max_length=250, blank=False)
content = models.CharField(max_length=15000,
help_text="Write Your thought here...")
creation_time = models.DateTimeField(auto_now_add=True, editable=False)
likes = models.ManyToManyField(User, blank=True, related_name='likes')
views.py
def home(request):
template = loader.get_template('home.html')
all_posts = Posts.objects.all()
context = {
'all_posts': all_posts,
}
return HttpResponse(template.render(context, request))
When i Use {{ post.likes }} what renders on page is auth.User.None

You will have to traverse over all the likes for the selected post
Try something like this:
{% for post in all_posts %}
{% for like in post.likes.all %}
{{ like }}
{% endfor %}
{% endfor %}