Python Pyramid - Hello World

Example

To check whether Pyramid along with its dependencies are properly installed, enter the following code and save it as hello.py, using any Python-aware editor.

from wsgiref.simple_server import make_server
from pyramid.config import Configurator
from pyramid.response import Response

def hello_world(request):
   return Response( Hello World! )
   
if __name__ ==  __main__ :
   with Configurator() as config:
      config.add_route( hello ,  / )
      config.add_view(hello_world, route_name= hello )
      app = config.make_wsgi_app()
   server = make_server( 0.0.0.0 , 6543, app)
   server.serve_forever()

The Configurator object is required to define the URL route and bind a view function to it. The WSGI apppcation object is obtained from this config object is an argument to the make_server() function along with the IP address and port of localhost. The server object enters a pstening loop when serve_forever() method is called.

Run this program from the command terminal as.

Python hello.py

Output

The WSGI server starts running. Open the browser and enter http://loccalhost:6543/ in the address bar. When the request is accepted, the hello_world() view function gets executed. It returns the Hello world message. The Hello world message will be seen in the browser window.

As mentioned earper, the development server created by make_server() function in the wsgiref module is not suited for production environment. Instead, we shall use Waitress server. Modify the hello.py as per the following code −

from pyramid.config import Configurator
from pyramid.response import Response
from waitress import serve

def hello_world(request):
   return Response( Hello World! )
   
if __name__ ==  __main__ :
   with Configurator() as config:
      config.add_route( hello ,  / )
      config.add_view(hello_world, route_name= hello )
      app = config.make_wsgi_app()
      serve(app, host= 0.0.0.0 , port=6543)

All other functionapty is same, except we use serve() function of waitress module to start the WSGI server. On visiting the / route in the browser after running the program, the Hello world message is displayed as before.

Instead of a function, a callable class can also be used as a view. A callable class is the one which overrides the __call__() method.

from pyramid.response import Response
class MyView(object):
   def __init__(self, request):
      self.request = request
   def __call__(self):
      return Response( hello world )