I'm developing a blog site using Django. My site will allow users to comment on any of my blog posts and also reply to each other and will be displayed using a 'threaded comments' structure (I haven't started user functionality yet, just comments). I've got the threaded comments to work properly using django-mptt (at least, for now), but I have NO CLUE if the route or steps I'm taking are in the right direction. Almost all the tutorials I've gone through only scratch the surface when it comes to comments and doesn't talk about threaded comments in django. I want some experienced/professional advice on what I might be doing wrong and what I could be doing better. The last thing I want is to find out there was a much more acceptable way of going about, after hours of work put in.
So, here is a list of what I need clarity on:
django-mptt:
I chose this because I can afford slower write times. My site will have more reads than writes. Is this option okay for my case? Is there a better alternative I don't know about?
What should I do if my site does end up having lots of commenting activity? What could I do to optimize tree restructuring? Or would I be better off switching to an adjacency list?
My MPTT comment model has a ForeignKey referenced to itself (for replies). Is this the right way? Or should I create a separate reply model?
The way I insert a reply to another user's comment in the tree is using a hidden input within the form that's within the mptt recursive template tags, and return the input value (which is the id of the comment that the reply is for) and set the parent of the reply to that input value. Is this an accepted method?
Multiple forms on one HTML page
I have two forms on my blog post HTML page. One to comment on the blog post, and one to reply to a user's comment. Is this accepted? Or should I create different URLs and view functions for different forms? I did it this way because I wanted a Reddit style commenting system. I don't want it to have to go to a different page to comment or reply.
If a user comments on my blog post, the hidden input value within the reply form returns nothing, therefore I get an error when trying to assign it to a variable in the views.py function. I used a try/except block to fix it. Is there a better way around this?
I'm sorry if these are noob questions and for my post being so long. I just want to do things the best way possible using realistic solutions for a beginner. Any feedback would help. Thank you! Here's my code for my blog app.
models.py
from django.db import models
from mptt.models import MPTTModel, TreeForeignKey
class Post(models.Model):
"""Blog post"""
title = models.CharField(max_length=200)
body = models.TextField()
date_added = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.body[:50] + '...'
class Comment(MPTTModel):
"""User comment"""
post = models.ForeignKey(Post, related_name='comments',on_delete=models.CASCADE)
parent = TreeForeignKey('self', null=True, blank=True, related_name='children',db_index=True, on_delete=models.CASCADE)
user_comment = models.CharField(max_length=500, unique=True)
date_added = models.DateTimeField(auto_now_add=True)
# approved = models.BooleanField(default=False)
class MPTTMeta:
order_insertion_by = ['date_added']
def __str__(self):
return self.user_comment[:20]
'approved' is commented out because I get a 'no such column: approved' error for some weird reason.
forms.py
from django import forms
from .models import Post, Comment
class CommentForm(forms.ModelForm):
class Meta:
model = Comment
fields = ['user_comment']
views.py
from django.shortcuts import render
from django.http import HttpResponseRedirect
from django.urls import reverse
from .models import Post
from .forms import CommentForm
def posts(request):
"""Show all blog posts"""
posts = Post.objects.order_by('-date_added')
context = {
'posts': posts
}
return render(request, 'posts/posts.html', context)
def post(request, post_id):
"""Show single blog post"""
post = Post.objects.get(id=post_id)
comments = post.comments.all()
if request.method != 'POST':
comment_form = CommentForm()
else:
comment_form = CommentForm(data=request.POST)
try:
parent_id = request.POST['comment_id']
except:
pass
if comment_form.is_valid():
comment = comment_form.save(commit=False)
comment.post = post
comment.parent = comments.get(id=parent_id)
comment.save()
return HttpResponseRedirect(reverse('posts:post', args=[post_id]))
context = {
'post': post,
'comment_form': comment_form,
'comments': comments,
}
return render(request, 'posts/post.html', context)
post.html
{% extends 'posts/base.html' %}
{% block blog_content %}
<h1>Post page!</h1>
<h3>{{ post.title }}</h3>
<h4>{{ post.date_added }}</h4>
<p>{{ post.body }}</p>
<form method="post" action="{% url 'posts:post' post.id %}">
{% csrf_token %}
{{ comment_form.as_p }}
<button type="submit">Add comment</button>
</form>
{% load mptt_tags %}
{% recursetree comments %}
<h5>{{ node.date_added }}</h5>
<p>{{ node.user_comment }}</p>
<form method="post" action="{% url 'posts:post' post.id %}">
{% csrf_token %}
{{ comment_form.as_p }}
<input type="hidden" name="comment_id" value="{{ node.id }}">
<button type="submit">Reply</button>
</form>
{% if not node.is_leaf_node %}
<div style="padding-left: 20px">
{{ children }}
</div>
{% endif %}
{% endrecursetree %}
{% endblock %}
urls.py
from django.urls import path
from . import views
app_name = 'posts'
urlpatterns = [
path('posts/', views.posts, name='posts'),
path('posts/<int:post_id>/', views.post, name='post'),
]
MPTT trees are great for getting a list of subnodes or node counts. They are costly for adding/inserting nodes and the cost increases linearly with the size of the three. They are designed to fit tree data into relational databases. Also, don't get fooled by "I'll have much more reads than writes". Ideally, most of the reads should hit a cache, not the database under it.
Why not skip the relational database and go with a NoSQL database that can natively store trees? There are easy integrations for Django and pretty much every NoSQL database you can thing about.
Related
Why my custom template tag doesn't work?
templatetags.py:
from django import template
from ..models import User
register = template.Library()
#register.inclusion_tag('main/post_detail.html', takes_context=True)
def get_user_liked_posts():
request = context['request']
user = User.objects.get(username=request.user.username)
liked_posts = []
for post in user.liked_posts.all():
liked_posts.append(post.name)
return {'liked_posts': liked_posts}
post_detail.html:
{% load static %}
{% load templatetags %}
<nav class="blog-pagination" aria-label="Pagination">
<span id="likes_count">{{ post.likes_count }}</span>
{% if post.name in liked_posts %}
<button id="like_button" class="btn btn-outline-primary btn-primary text-
white">Like</button>
{% else %}
<button id="like_button" class="btn btn-outline-primary">Like</button>
{% endif %}
</nav>
views.py:
class PostDetailView(DetailView):
model = Post
slug_field = 'url'
class LikePostView(View):
def post(self, request, slug):
post = Post.objects.get(id=request.POST['id'])
user = User.objects.get(username=request.user.username)
if request.POST['like'] == 'true':
post.likes_count += 1
user.liked_posts.add(post)
else:
post.likes_count -= 1
user.liked_posts.remove(post)
user.save()
post.save()
return redirect('post_detail', slug)
models.py:
class Post(models.Model):
"""
This is post model
"""
name = models.CharField(max_length=150, blank=False)
article = models.TextField(blank=False)
image = models.ImageField(upload_to='uploads/', blank=True)
likes_count = models.IntegerField(default=0)
url = models.CharField(max_length=150, blank=False)
def get_absolute_url(self):
return reverse('post_detail', kwargs={'slug': self.url})
I want to check if the post is in the liked post of the current user, but it doesn't work.
It doesn't show any errors, it just does nothing.
User in my app must like or unlike posts. In models, I have many to many relationship user with the post. I want to check if the user likes this post
The problem is that you don't even use the template tag, furthermore this is not even needed as you can simply write something like so in the template:
{% if post in request.user.liked_posts.all %}
A Liked post
{% else %}
Not a liked post
{% endif %}
But this is a bit inefficient as we are getting all the posts liked by the user just to check if they like some post. Also if this were in a loop with multiple posts we would be making a query for each post.
Instead we can simply annotate whether the user likes a post in the view itself using an Exists subquery [Django docs] on the through model of the many to many:
from django.db.models import Exists, OuterRef
class PostDetailView(DetailView):
model = Post
slug_field = 'url'
def get_queryset(self):
queryset = super().get_queryset()
queryset = queryset.annotate(
liked_by_user=Exists(
User.liked_posts.through.objects.filter(
post_id=OuterRef("pk"),
user_id=self.request.user.id
)
)
)
return queryset
Now in the template we can simply write:
{% if post.liked_by_user %}
A Liked post
{% else %}
Not a liked post
{% endif %}
Note: Your way of saving the count similarly can simply be turned into an annotation using the Count aggregation function [Django
docs].
Generally one should not store calculated attributes in a column since
that might lead to inconsistent data when updating and forgetting to update the related count, etc.
I am building a BlogApp and I am stuck on an Problem.
What i am trying to do
I am trying to build like Featuring Post system. That If user click on feature this post then post should be add in featured posts.
The Problem
When i click on Feature this Post then it doesn't add the post in featured post page.
What have i tried
I also made a another model for Featuring Post BUT it didn't work so then i again implement in Post Model
views.py
def featured(request,user_id):
post = get_object_or_404(Post,post_owner=user_id)
if request.user.is_authenticated:
if request.method == 'POST':
post.featured.add(post)
context = {'post':post}
return render(request, 'featured_posts.html', context)
models.py
class Post(models.Model):
post_owner = models.ForeignKey(User,default='',null=True,on_delete=models.CASCADE)
post_title = models.CharField(max_length=500,default='')
featured = models.ManyToManyField(User,related_name='featured',blank=True,default='')
urls.py
path('featured/<int:user_id>/',views.featured,name='featured'),
detail_view.html
{{ data.post_title }}
Feature this Post
featured_posts.html
{% for s in post.featured %}
{{ s.post_title }}
{% endfor %}
I don't know what i am doing wrong.
Any help would be appreciated.
Thank You in Advance.
You write post.featured.add(post) which is incorrect as featured is a many to many relationship between user and post. You likely want to write:
post.featured.add(request.user)
OR
request.user.featured.add(post)
Also you write if request.method == 'POST': yet the view is reached by a normal get request (you use an anchor tag). Remove that condition and it will work. (Best would be to change the anchor to a form with a submit button)
Also to display featured posts of a user:
{% for s in request.user.featured.all %}
{{ s.post_title }}
{% endfor %}
I am creating a Q&A website for practice, I created the answer and the question model and linked them together, however I can not access the template that I set for the deletion of the answer model, I created a DeleteView to delete the question. Here is the code:
views.py:
class Politics_post_details(DeleteView):
model = PoliticsPost
context_object_name = 'politicsposts'
pk_url_kwarg = 'qid'
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
# now you can get any additional information you want from other models
question = get_object_or_404(PoliticsPost, pk=self.kwargs.get('qid'))
context['answers'] = Answer.objects.filter(post=question).order_by('-date_posted')
return context
class AnswerDelete(UserPassesTestMixin,DetailView):
model = Answer
success_url = reverse_lazy('Lisk home')
pk_url_kwarg = 'aid'
def test_func(self):
answer = self.get_object()
if self.request.user ==answer.author:
return True
return False
urls.py(not root):
path('politicspost/<int:qid>/createanswer/',views.CreateAnswer.as_view(template_name='lisk_templates/createanswer.html'),name = 'Answer'),
path('politicspost/<int:qid>/answer/<int:aid>/delete/',views.AnswerDelete.as_view(template_name = 'lisk_templates/answer_delete.html'),name='Answer_Delete'),
path('politicspost/<int:qid>/',views.Politics_post_details.as_view(template_name='lisk_templates/politics_post_details.html'),
I created the template but whenever I try to access it, it gives me an error as follows:
NoReverseMatch at /politicspost/29/
Reverse for 'Answer_Delete' with arguments '(36,)' not found. 1 pattern(s) tried: ['politicspost/(?P<qid>[0-9]+)/answer/(?P<aid>[0-9]+)/delete/$']
Thanks in advance.
answer_delete.html:
{%extends "lisk_templates/base.html"%}
{% block title %}
Page title
{% endblock title %}
{% block body%}
<div class="feed" style="background-color:lightred;"><form method="POST">
{% csrf_token %}
<h3>Are you sure that you want to delete this answer: <br>
{{ object.content }}</h3>
<button id="signin" type="submit">Yes</button> No
</form>
</div>
{% endblock body %}
You have a number of issues. The biggest one is that you have switched DeleteView and DetailView (your DeleteView is a DetailView and vice versa).
And then you should either rename your template to answer_confirm_delete or add the template_name_suffix to your DeleteView. See the documentation for further details:
https://docs.djangoproject.com/en/3.0/ref/class-based-views/generic-editing/#django.views.generic.edit.DeleteView
If you use Django's DeleteView, you don't need to specify a url in the template, it will do all the work for you. Just make sure you specify the url correctly in your urls.py. Fix these issues and see if it works then.
May Be This Might Work For You, Because You Never Used The Import Of DeleteView
from django.views.generic import DeleteView
"""This Is From My Blog App, That I Used For My Blog App, Hope This Will Help"""
class PostDeleteView(LoginRequiredMixin, DeleteView):
model = Post
success_url = reverse_lazy('post_list')
Happy Coding, let me know if there are any issues with this I'am Up for you!
I started to learn Django today, but I am stuck at using forms. I have created two forms: /contact and /blog-new. The form at the Contact page is working fine, but the one at /blog-new is redirecting me to the home page after the submission button is pressed and no information is printed in the terminal nor saved in the database.
Code on Github
I appreciate if someone can explain to me what I did wrong as I cannot figure it out. Thank you!
mysite/blog/forms.py
from django import forms
from .models import BlogPost
class BlogPostModelForm(forms.ModelForm):
class Meta:
model = BlogPost
fields = ['title', 'slug', 'content']
mysite/blog/views.py
from .forms import BlogPostModelForm
def blog_post_create_view(request):
# create objects
# ? use a form
# request.user -> return something
form = BlogPostModelForm(request.POST or None)
if form.is_valid():
print(form.cleaned_data)
form.save()
form = BlogPostModelForm()
template_name = 'form.html'
context = {'form': form}
return render(request, template_name, context)
mysite/blog/models.py
from django.db import models
# Create your models here.
class BlogPost(models.Model):
title = models.TextField()
slug = models.SlugField(unique=True)
content = models.TextField(null=True, blank=True)
mysite/mysite/urls.py
from blog.views import (
blog_post_create_view,
)
urlpatterns = [
..
path('blog-new', blog_post_create_view),
..
]
mysite/templates/form.html
{% extends "base.html" %}
{% block content %}
{% if title %}
<h1>{{ title }}</h1>
{% endif %}
<form method='POST' action='.'> {% csrf_token %}
{{ form.as_p }}
<button type='submit'>Send</button>
</form>
{% endblock %}
You need to point to right url in action attribute of form.
<form action="/blog-new/" method="post">
{% csrf_token %}
{{ form }}
<input type="submit" value="Submit">
</form>
I think it's not necessary in your case but you could also refactor your view to match the docs.
from django.http import HttpResponseRedirect
from django.shortcuts import render
from .forms import SomeForm
def some_view(request):
# if this is a POST request we need to process the form data
if request.method == 'POST':
# create a form instance and populate it with data from the request:
form = SomeForm(request.POST)
# check whether it's valid:
if form.is_valid():
# process the data in form.cleaned_data as required
# ...
# redirect to a new URL:
return HttpResponseRedirect('/thanks/')
# if a GET (or any other method) we'll create a blank form
else:
form = SomeForm()
return render(request, 'template_name.html', {'form': form})
You need to point to right url in action attribute of form.
That was not actually the solution but something that helped me to figure out what was wrong.
It is not necessary to point to /blog-new/ as . for action will point to the same page, but I have tried with /blog-new/ as action URL and I was surprised to see that /blog-new/ page doesn't exist.
The bug was in mysite/mysite/urls.py for missing a /:
path('blog-new', blog_post_create_view),
It is funny (and annoying) how a symbol like / missing from your code will mess up everything and make you spend hours trying to find a solution as simple as that.
Thank you for your time spend to have a look over my code and try to help me!
I am using modelform for a model department is not working. (BTW,I have a custom user model also in users app of same project). All I am getting is a 'Test up' button in the html output. Also, Change E-mail and Signout are displaying may be consequence to usage of allauth in middleware. I don't know whether allauth is interfering with this or not (hope not).I have added department model to admin but there is some strange thing appearing in admin described below
I have tried to debug with many ways.
Here is the model
from django.db import models
from django.conf import settings
from users.models import User,UserProfile
# Create your models here.
class department(models.Model):
Dept_CHOICES = (
(1, 'Inventory'),
(2, 'Dispatch'),
)
dept_type = models.PositiveSmallIntegerField(choices=Dept_CHOICES,default=1,unique=False),
HOD = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE,),
Invest = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE,),
def __str__(self):
return self.dept_type
Here is the view code
def add_model(request):
if request.method == "POST":
form = departForm(request.POST)
if form.is_valid():
model_instance = form.save(commit=False)
model_instance.save()
return redirect('/')
else:
form = departForm()
return render(request, "test.html", {'form': form})
base.html
<!-- templates/base.html -->
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<main>
{% block content %}
{% endblock %}
</main>
</body>
</html>
test.html
{% extends 'base.html' %}
{% block content %}
<div class = "container">
<h2>Sign up</h2>
<form method="post">
{% csrf_token %}
{{ form.as_p }}
<button type="submit">Test up</button>
</form>
</div>
{% endblock %}
admin.py
from core1.models import department
# Register your models here.
#admin.register(department)
class DepartmentAdmin(admin.ModelAdmin):
pass
output in admin of the site is a single field with strange name of
<django.db.models.fields.PositiveSmallIntegerField>
For additional info, I am using class view and function view in the same views.py file. Hope it is allowed.
I expect the form to be displayed
Tried form.as_p but getting
<<bound method BaseForm.as_p of <departForm bound=False, valid=False, fields=()>>
Tried form.valid
<bound method BaseForm.is_valid of <departForm bound=False, valid=False, fields=()>>
Solved on my own !
I checked Admin site. There is no department model displaying. This means either I am not migrating properly or my department model has an issue
My department model has all fields ending with a , (comma). Same removed and made the model more robust and without error.
Removed all migrations and done fresh migrate
Modified Admin as follows
# Register your models here.
class departmentadmin(admin.ModelAdmin):
fields = ['HOD', 'Investigator', 'dept_type']
list_display = ('HOD','Investigator','dept_type')
pass
admin.site.register(department, departmentadmin)
Now admin also displaying dpartment and form also displaying departments with required out put..