JupyterLab Server Components

import os
from tornado import web
from jupyterlab_server.server import ServerApp
from jupyterlab_server.handlers import LabHandler

# Define a simple custom handler
class MyCustomHandler(LabHandler):
    @web.authenticated
    def get(self, path=''):
        self.finish(f"Hello from My Custom Handler! Path: {path}")

# This function would typically be in a server extension module
# (e.g., `my_extension.py`) and discovered by Jupyter Server.
def load_jupyter_server_extension(server_app: ServerApp):
    host_pattern = ".*$"
    base_url = server_app.base_url
    route_pattern = web.url(f"/{os.environ.get('MY_CUSTOM_ROUTE_PREFIX', 'my-api')}(.*)", MyCustomHandler)
    server_app.web_app.add_handlers(host_pattern, [route_pattern])
    server_app.log.info(f"MyCustomHandler enabled at {base_url}my-api")

# To run this for testing, you'd integrate it with a Jupyter Server setup.
# This block is illustrative and not a direct executable for end-users
# as jupyterlab-server is a component library.
# For a real setup, this would be loaded as a server extension.
# Example command to launch JupyterLab with this extension:
# jupyter lab --ServerApp.extra_static_paths='["$(pwd)"]' \
#  --ServerApp.jpserver_extensions='{"my_extension": true}'

# For testing purposes (not how it's usually run in production):
# if __name__ == "__main__":
#     from jupyter_server.serverapp import ServerApp as _JupyterServerApp
#     class CustomLabServerApp(_JupyterServerApp):
#         def initialize_settings(self):
#             super().initialize_settings()
#             load_jupyter_server_extension(self)
#     CustomLabServerApp.launch_instance()