Enable any server (basic)¶
Audience: Users who want to enable an arbitrary server/UI.
Prereqs: Basic python knowledge.
What is a server?¶
A server is a program that enables other programs or users to connect to it. As long as your server can listen on a port, you can enable it with a Lightning App.
Add a server to a component¶
Any server that listens on a port, can be enabled via a work. For example, here’s a plain python server:
import socketserver
from http import HTTPStatus, server
class PlainServer(server.SimpleHTTPRequestHandler):
def do_GET(self):
self.send_response(HTTPStatus.OK)
self.end_headers()
# Data must be passed as bytes to the `self.wfile.write` call
html = b"<h1 style='color: blue'> Hello lit world </div>"
self.wfile.write(html)
httpd = socketserver.TCPServer(("localhost", "3000"), PlainServer)
httpd.serve_forever()
To enable the server inside the component, start the server in the run method and use the self.host and self.port properties:
import lightning as L
import socketserver
from http import HTTPStatus, server
class PlainServer(server.SimpleHTTPRequestHandler):
def do_GET(self):
self.send_response(HTTPStatus.OK)
self.end_headers()
# Data must be passed as bytes to the `self.wfile.write` call
html = b"<h1 style='color: blue'> Hello lit world </div>"
self.wfile.write(html)
class LitServer(L.LightningWork):
def run(self):
httpd = socketserver.TCPServer((self.host, self.port), PlainServer)
httpd.serve_forever()
Route the server in the root component¶
The final step, is to tell the Root component in which tab to render this component’s output:
In this case, we render the LitServer output in the home tab of the application.
import lightning as L
import socketserver
from http import HTTPStatus, server
class PlainServer(server.SimpleHTTPRequestHandler):
def do_GET(self):
self.send_response(HTTPStatus.OK)
self.end_headers()
# Data must be passed as bytes to the `self.wfile.write` call
html = b"<h1 style='color: blue'> Hello lit world </div>"
self.wfile.write(html)
class LitServer(L.LightningWork):
def run(self):
httpd = socketserver.TCPServer((self.host, self.port), PlainServer)
httpd.serve_forever()
class Root(L.LightningFlow):
def __init__(self):
super().__init__()
self.lit_server = LitServer(parallel=True)
def run(self):
self.lit_server.run()
def configure_layout(self):
tab1 = {"name": "home", "content": self.lit_server}
return tab1
app = L.LightningApp(Root())
We use the parallel=True argument of LightningWork to run the server in parallel
while the rest of the Lightning App runs everything else.
Run the app¶
Start the app to see your new UI!
lightning_app run app app.py
To run the app on the cloud, use the --cloud argument.
lightning_app run app app.py --cloud
Interact with a component from the server¶
Todo
how do we do this?
Interact with the server from a component¶
Todo
how do we do this?
Examples¶
Here are a few example apps that expose a server via a component:
