Django filter function on HTML template - django

Question

I'm stuck on a problem. I need to filter all of the listings using the list.id in the for loop. Unfortunately, the filter function in Django could not be parsed. Is there another solution or is there a way to work around it? How can you run a function in Django HTML template. Thanks!
index.html
{% extends "auctions/layout.html" %}
{% block body %}
<h2>Active Listings</h2>
{% if not listing %}
<h3>Nothing listed...</h3>
{% endif %}
{% for list in listing %}
<h3>Listing: {{ list.title }}</h3>
{% if list.photo != "" %}
<img src="{{ list.photo }}">
{% endif %}
<p>{{ list.description }}</p>
{% if not bids.filter(listing=list.id) %} #This line could not be parsed
<h5>${{ list.price }}</h5>
{% else %}
<h5>${{ bids.filter(listing=list.id).order_by(-bids).first().bids }}</h5> #This line could not be parsed
{% endif %}
<p>
{% if not bids.filter(listing=list.id).count() %} #This line could not be parsed
0
{% else %}
{{ bids.filter(listing=list.id).count() }} #This line could not be parsed
{% endif %}
bid(s) so far.
{% if bids.filter(listing=list.id).order_by(-bids).first().bidder == user.username %} #This line could not be parsed
Your bid is the current bid.
{% elif not bids.filter(listing=list.id).order_by(-bids).first().bidder %} #This line could not be parsed
There is no bid.
{% elif bids.filter(listing=list.id).order_by(-bids).first().bidder != user.username %} #This line could not be parsed
{{ bids.filter(listing=list.id).order_by(-bids).first().bidder }} is the current bid. #This line could not be parsed
{% endif %}
</p>
{% if user.username != list.user and user.is_authenticated %}
<form action="{% url "index" %} method="post">
{% for form in forms %}
{{ form }}
<input type="submit" value="Bid">
</form>
{% endfor %%}
{% endif %}
<h4>Details</h4>
<ul>
{% if user.username == list.user %}
<li>Listed by: You</li>
{% else %}
<li>Listed by: {{ list.user }}</li>
{% endif %}
<li>Category: {{ list.category }}</li>
</ul>
<hr>
{% endfor %}
{% endblock %}
views.py
from .models import User, AuctionList, Bids, Comments
from .forms import AuctionForm, BidsForm
def index(request):
if request.method == "POST":
pass
else:
AL = AuctionList.objects.all()
Bd = Bids.objects.all()
forms = BidsForm()
return render(request, "auctions/index.html", {
"listing": AL.order_by("id"),
"bids": Bd,
"forms": forms
})
models.py
from django.contrib.auth.models import AbstractUser
from django.db import models
class User(AbstractUser):
pass
class AuctionList(models.Model):
CATEGORY_CHOICES = [
('Books', 'Books'),
('Business & Industrial', 'Business & Industrial'),
('Clothing, Shoes & Accessories', 'Clothing, Shoes & Accessories'),
('Collectibles', 'Collectibles'),
('Consumer Electronics', 'Consumer Electronics'),
('Crafts', 'Crafts'),
('Dolls & Bears', 'Dolls & Bears'),
('Home & Garden', 'Home & Garden'),
('Motors', 'Motors'),
('Pet Supplies', 'Pet Supplies'),
('Sporting Goods', 'Sporting Goods'),
('Sports Mem, Cards & Fan Shop', 'Sports Mem, Cards & Fan Shop'),
('Toys & Hobbies', 'Toys & Hobbies'),
('Antiques', 'Antiques'),
('Computers/Tablets & Networking', 'Computers/Tablets & Networking')
]
id = models.AutoField(primary_key=True)
user = models.CharField(max_length=20, default='None')
title = models.CharField(max_length=20)
category = models.CharField(
max_length=30, choices=CATEGORY_CHOICES, default='Books')
description = models.TextField()
price = models.FloatField()
photo = models.URLField(max_length=200, blank=True)
def __str__(self):
return f"({self.id}) | Title: {self.title} | Category: {self.category} | Price: {self.price} | Posted by: {self.user}"
class Bids(models.Model):
bidder = models.CharField(max_length=20, default='None')
listing = models.ForeignKey(
AuctionList, on_delete=models.CASCADE, related_name="bids")
bids = models.FloatField()
def __str__(self):
return f"Listing Key: {self.listing} | Bids: {self.bids}"

Answer 1

You can create another function in your views.py and pass it in your index function (example below to give you some idea in views.py & index.html)
def build_auctions_layout(username):
final_html = None
for list in listing:
final_html = '<h3>Listing: {}</h3>'.format(list.title)
if list.photo:
final_html += '<img src="{}"'.format(list.photo)
final_html += '<p>{}</p>'.format(list.description)
if not list.bids: #This line could not be parsed
final_html += '<h5>${}</h5>'.format(list.price)
else:
final_html += '<h5>${}</h5>'.format(list.bids.order_by(-bids).first().bids ) #This line could not be parsed
final_html += '<p>{} bid(s) so far'.format(list.bids.count())
if list.bids.order_by(-bids).first().bidder == username:
final_html += 'Your bid is the current bid.</p>'
else:
final_html += 'There is no bid.</p>'
return final_html
def index(request):
if request.method == "POST":
pass
else:
AL = AuctionList.objects.all()
Bd = Bids.objects.all()
forms = BidsForm()
return render(request, "auctions/index.html", {
"listing": AL.order_by("id"),
"bids": Bd,
"forms": forms,
"auctions_layout": build_auctions_layout(request.user.username)
})
#auctions/index.html
{% extends "auctions/layout.html" %}
{% block body %}
<h2>Active Listings</h2>
{% if not listing %}
<h3>Nothing listed...</h3>
{% endif %}
{{auctions_layout|safe}}
......

Answer 2

The answer is yes you can run filter function inside your html template. Infact filter functions are meant for and frequently used everywhere in django templates which you can find in django more precisely as Custom template filters
You can also create one filter function as per your requirement and use it anywhere inside your template which is known as Django Templatetags. These template tags are nothing but a sort of functions which you define yourself and implement in templates.Here I explain you step by step:
For referene, my project name is "working_blog_python" and app name is "branch"
1. open your terminal and type
(working_blog_python) $ cd branch
(working_blog_python) $ mkdir templatetags
(working_blog_python) $ touch templatetags/any_name_tags.py
2.Now inside your
any_name_tags.py
you can write your filter function like this
from django import template
register = template.Library()
#register.filter_function
def hrs(self):
return self.name.replace('-', ' ')
3.Now you can use this hrs() function anywhere in your templates, but don't forget to load {% load name_tags %} name_tag inside your template.
<p>Shop is located in {{branch.state | hrs | title}}.</p>