Web Server Tutorial

Create a simple web server with ASAB.

The code

#!/usr/bin/env python3
import asab.web.rest


class MyWebApplication(asab.Application):

    def __init__(self):
        super().__init__()

        # Create the Web server
        web = asab.web.create_web_server(self)

        # Add a route to the handler method
        web.add_get('/hello', self.hello)

    # This is the web request handler
    async def hello(self, request):
        return asab.web.rest.json_response(
            request,
            data="Hello, world!\n"
        )


if __name__ == '__main__':
    app = MyWebApplication()
    app.run()

To start the application, store above code in a file app.py.

Execute $ python3 ./app.py to run it.

The ASAB web server is now available at http://localhost:8080/.

Deeper look

ASAB Application

#!/usr/bin/env python3
import asab.web.rest

class MyWebApplication(asab.Application):

    def __init__(self):
        super().__init__()

if __name__ == '__main__':
    app = MyWebApplication()
    app.run()

This is a ASAB code that declares the application class and runs it.

Create a Web server

The asab.web module provides a create_web_server() function that simplifies creation of the Web server in the ASAB application.

web = asab.web.create_web_server(self)

Install the handler

web.add_get('/hello', self.hello)

...

async def hello(self, request):
    return asab.web.rest.json_response(
        request,
        data="Hello, world!\n"
    )

The handler method hello() is installed at the web server at /hello endpoint. HTTP method is GET.

It means that if you access the web server with a path /hello, it will be handled by a hello(...) method. A handler method must be a coroutine.