Django : How to check if element in the queryset? - django

Question

I'd liket to make is current_user exist in queryset, so i try:
{% if obj.payer.name == current_user.username %}
{{ obj.price|intcomma }} / {{obj.dutch_payer.all.count}}</p>
<p>={{ obj.price|div_payer_me:obj.dutch_payer.all.count|intcomma }}</p>
{% else %}
{% if current_user.username in obj.dutch_payer.filter(name=current_user.username) %}
{{ obj.price|intcomma }} / {{obj.dutch_payer.all.count|add1}}</p>
<p>={{ obj.price|div_payer_notme:obj.dutch_payer.all.count|intcomma }}</p>
{% else %}
0
{% endif %}
{% endif %}
but error occur :
Could not parse the remainder: '(name=current_user.username)' from 'obj.dutch_payer.filter(name=current_user.username)'
Tempfriend model:
class Tempfriend(core_models.TimeStampedModel):
name = models.CharField(max_length=30)
belongs_to = models.ForeignKey(
user_models.User, on_delete=models.CASCADE, related_name="belongs_to")
def __str__(self):
return self.name
moneylog model:
class Moneylog(core_models.TimeStampedModel):
moneybook = models.ForeignKey(
moneybook_models.Moneybook, on_delete=models.CASCADE)
pay_day = models.DateTimeField(default=NOW)
payer = models.ForeignKey(
tempfriend_models.Tempfriend, on_delete=models.CASCADE, related_name="payer")
dutch_payer = models.ManyToManyField(
tempfriend_models.Tempfriend, related_name="dutch_payer", blank=True)
price = models.IntegerField()
category = models.CharField(max_length=10)
memo = models.TextField()
objects = models.Manager()
as you see, dutch_payer and current_user is different model.
How can I check the is there current_user in dutch_payer?
Tried:
#register.filter
def user_in_dutch_payers(current_user, obj):
return obj.dutch_payer.filter(name=current_user.username).exists()

Answer 1

You can't use queries directly in template (templates are writen in Django template language). Instead you can use simple tag:
Add your custom tag(s) in settings.py:
TEMPLATES = [
{
'OPTIONS': {
'builtins': [
'myprojectname.templatetags.custom_tags',
Next, put this file inside your app templatetags/custom_tags.py
from django import template
register = template.Library()
#register.simple_tag
def user_in_dutch_payers(current_user, obj):
return obj.dutch_payer.filter(name=current_user.username).exists()
And finally use tag in template:
{% user_in_dutch_payers current_user obj as check_user_in_dutch_payers %}
{% if check_user_in_dutch_payers %}
{{ obj.price|intcomma }} / {{obj.dutch_payer.all.count|add1}}</p>
<p>={{ obj.price|div_payer_notme:obj.dutch_payer.all.count|intcomma }}</p>
{% else %}
0
{% endif %}