Create dynamic sitemap with third-level link ⚡️ django.contrib.sitemaps

settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    ...
    'django.contrib.sitemaps',
]

sitemap.py

from django.contrib import sitemaps
from django.urls import reverse

from yourapp.models import MainClass, RelatedClass

class ManyToManyViewSitemap(sitemaps.Sitemap):
    priority = 0.5
    changefreq = 'monthly'
    i18n = True
    
    _allentry = MainClass.objects.language().all()
    _midlevel = ''
    
    def items(self):
        items = []
        for main_element in self._allentry:
            items.append(main_element)
            for related_element in main_element.related_field.all():
                items.append(related_element)
        return items

    def location(self, item):
        if isinstance(item,RelatedClass):
            return reverse('your_third_level_url', kwargs={'main': self._midlevel, 'related': item.permalink})
        else:
            if self._midlevel != item.permalink:
                self._midlevel=item.permalink
                return reverse('your_second_level_url', kwargs={'main': item.permalink})

urls.py

from django.contrib.sitemaps.views import sitemap
from .sitemap import *

sitemaps = {
    ...
    'm2m': ManyToManyViewSitemap,
    ...
 }

urlpatterns = [
   ...
    url(_(r'^abc/(?P<main>[-\w]+)$'),  yourview, name='your_second_level_url'),
    url(_(r'^abc/(?P<main>[-\w]+)/(?P<related>[-\w]+)$'),  yourview, name='your_third_level_url'),
    url(r'^sitemap\.xml$', sitemap, {'sitemaps': sitemaps},
        name='django.contrib.sitemaps.views.sitemap'),
    ...
]