Python Pyramid - Route Prefix

Many times, similar URL patterns are registered with different routes in more than one Python code modules. For example, we have a student_routes.py where /list and /add URL patterns are registered with 'list' and 'add' routes. The view functions associated with these routes are list() and add(), respectively.

#student_routes.py
from pyramid.config import Configurator
from pyramid.response import Response
from pyramid.view import view_config

@view_config( route_name='add')
def add(request):
   return Response('add student')
@view_config(route_name='list')
def list(request):
   return Response('Student list')
   
def students(config):
   config.add_route('list', '/list')
   config.add_route('add', '/add')
   config.scan()

These routes will eventually be registered when the students() function is called.

At the same time, there is book_routes.py, in which the same URLs /list and add/ are registered to 'show' and 'new' routes. Their associated views are list() and add() respectively. The module has books() function which adds the routes.

#book_routes.py
from pyramid.config import Configurator
from pyramid.response import Response
from pyramid.view import view_config

@view_config( route_name='new')
def add(request):
   return Response('add book')
@view_config(route_name='show')
def list(request):
   return Response('Book list')
def books(config):
   config.add_route('show', '/list')
   config.add_route('new', '/add')
   config.scan()

Obviously, there is a conflict between URL patterns as '/list' and '/add' point to two routes each and this conflict must be resolved. This is done by using the route_prefix parameter of the config.include() method.

The first parameter to config.include() is the function which adds the routes, and the second is the route_prefix string which will be prepended to the URL pattern used in the included function.

Hence, the statement

config.include(students, route_prefix='/student')

will result in the '/list' URL pattern changed to '/student/list' and '/add' becomes 'student/add'. Similarly, we can add prefix to these URL patterns in the books() function.

config.include(books, route_prefix='/books')

Example

The code that starts the server is as below −

from wsgiref.simple_server import make_server
from pyramid.config import Configurator
from pyramid.response import Response
from student_routes import students
from book_routes import books

if __name__ == '__main__':
   with Configurator() as config:
      config.include(students, route_prefix='/student')
      config.include(books, route_prefix='/book')
      app = config.make_wsgi_app()
   server = make_server('0.0.0.0', 6543, app)
   server.serve_forever()

Output

Let us run the above code and test the routes by following CURL commands.

C:\Users\Acer>curl localhost:6543/student/list
Student list
C:\Users\Acer>curl localhost:6543/student/add
add student
C:\Users\Acer>curl localhost:6543/book/add
add book
C:\Users\Acer>curl localhost:6543/book/list
Book list

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