Django custom URL mapping: date pattern not matched in template

Question

I am using Django 3.2

I have created a custom Date URL pattern matcher as follows:

helpers.py

from datetime import datetime

class DateConverter:
    regex = '\d{4}\d{2}\d{2}'

    def to_python(self, value):
        return datetime.strptime(value, '%Y%m%d')

    def to_url(self, value):
        return value

urls.py

from django.urls import path, register_converter

from . import views
from myproj.helpers import DateConverter

app_name = 'event'

register_converter(DateConverter, 'yyyymmdd')

urlpatterns = [
    path('', views.index, name='index'),
    path('detail/<int:event_id>/<slug:event_slug>', views.detail, name='detail'),
    path('archive/<yyyymmdd:start_date>/<yyyymmdd:end_date>', views.archive, name='archive'),        
]

index.html (relevant section)

  <div class="row">
    <a href="{% url 'event:archive' '2020101' '2020201' %}">Previous Events</a>
  </div>

I get the following error:

reverse for 'archive' with arguments '('2020101', '2020201')' not found. 1 pattern(s) tried: ['media/events/archive/(?P<start_date>\d{4}\d{2}\d{2})/(?P<end_date>\d{4}\d{2}\d{2})$']

How do I fix this?

Answer 1

Is it possible you're not passing enough digits in? Your DateConverter requires 4 + 2 + 2 = 8 digits and the numbers you are passing in only have 7 digits.

Answer 2

Your date strings are wrong. Indeed, it is interpreted as:

2020101
YYYYMMDD

It is thus missing a digit for the month, a correct date thus looks like:

{% url 'event:archive'   %}"