Python Falcon - Uvicorn

Quiz

Uvicorn uses uvloop and httptools libraries. It also provides support for HTTP/2 and WebSockets, which cannot be handled by WSGI. uvloop is similar to the built-in asyncio event loop. httptools library handles the http protocols.

Falcon's ASGI compliant application is launched on Uvicorn server with following command −

Uvicorn hellofalcon:app  reload

The --reload option enables the debug mode, so that any changes in app.py will be automatically reflected and the display on the client browser will be automatically refreshed. In addition, the following command-line options may be used −

--host TEXT	Bind socket to this host. [default 127.0.0.1]
--port INTEGER	Bind socket to this port. [default 8000]
--uds TEXT	Bind to a UNIX domain socket.
--fd INTEGER	Bind to socket from this file descriptor.
--reload	Enable auto-reload.
--reload-dir PATH	Set reload directories explicitly, default current working directory.
--reload-include TEXT	Include files while watching. Includes '*.py' by default
--reload-exclude TEXT	Exclude while watching for files.
--reload-delay FLOAT	Delay between previous and next check default 0.25
--loop [auto\|asyncio\|uvloop]	Event loop implementation. [default auto]
--http [auto\|h11\|httptools]	HTTP protocol implementation. [default auto]
--interface auto\|asgi\|wsgi	Select application interface. [default auto]
--env-file PATH	Environment configuration file.
--log-config PATH	Logging configuration file. Supported formats .ini, .json, .yaml.
--version	Display the Uvicorn version and exit.
--app-dir TEXT	Look for APP in the specified directory default current directory
--help	Show this message and exit.

The Uvicorn server can also be launched from within the program instead of the above command line. To do that, import uvicorn module and call uvicorn.run() method as shown below −

import uvicorn
if __name__ == "__main__":
   uvicorn.run("hellofalcon:app", host="0.0.0.0", port=8000, reload=True)

Change the hellofalcon.py code accordingly, and execute the same from command prompt. The result can be verified by the curl command or in the browser as explained earlier.

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