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 application 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 listening 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 earlier, 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 functionality 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')