Django - Dynamic URL

# views.py

from django.shortcuts import render
from .models import Post


def post_detail(request, pk):
    post = Post.objects.get(pk=pk)
    return render(request, 'post.html', {'post': post})


# urls.py

url(r'^post/(?P<pk>\d+)/$', post_detail, name='post_detail'),
url(r'^send_message/(?P<user_id>[\w]+)/(?P<text>\w+)/$', views.send_message, name="send_message"),