API Reference

This section provides detailed API documentation for the nanohub-gradio package.

Jupyter Magic Command

%set_dash_env [--port PORT] [--host HOST]

Configure environment variables for running Dash on nanoHUB.

Parameters:

• port (int) – Dash port (default: 8001)

• host (str) – Dash bind host (default: 0.0.0.0)

Environment Variables Set:

• DASH_REQUESTS_PATHNAME_PREFIX: Weber proxy path for requests (e.g., /weber/123/abc/456/proxy/8001/)

• DASH_ROUTES_PATHNAME_PREFIX: Set to /

• DASH_HOST: The host address for the Dash server

• DASH_PORT: The port number for the Dash server

• DASH_BASE_PROXY: Base proxy URL (e.g., https://proxy.nanohub.org)

Example:

%load_ext nanohubdash
%set_dash_env --port 8050 --host 0.0.0.0

Command-Line Tool

start_dash

Launch a Dash application with automatic proxy configuration and header injection.

Usage:

start_dash --app APP_PATH [--debug DEBUG] [--logo LOGO_URL]

Arguments:

--app APP_PATH

Required. Path to the Dash application Python file. The file must define app = dash.Dash(...).

--debug DEBUG

Optional. Enable debug mode (True/False). Default: False. When enabled:

• Hot reloading is active

• Detailed error messages are shown

• wrwroxy stream logging is enabled

--logo LOGO_URL

Optional. URL for the logo displayed in the header bar. Default: nanoHUB logo

Example:

start_dash --app myapp.py --debug True --logo https://example.com/logo.png

Header Injection:

When using start_dash, a header bar is automatically injected into your Dash app with:

• Logo image (customizable via --logo)

• “Submit a ticket” link for support

• “Terminate Session” button

Python API

nanohubdash module

nanohubdash.__version__

The current version of the nanohub-gradio package.

nanohubdash.load_ipython_extension(ipython)

Register the SetDashEnvMagic with IPython.

This function is called automatically when the extension is loaded via %load_ext nanohubdash.

Parameters:

ipython – The IPython shell instance.

class nanohubdash.SetDashEnvMagic

IPython magic class for setting up Dash environment on nanoHUB.

Provides the %set_dash_env line magic that configures environment variables needed for Dash applications running behind the nanoHUB weber proxy.

Environment Variables Reference

The following environment variables are used or set by nanohub-gradio:

Input Variables (read from environment):

Variable	Description
SESSION or SESSION_ID	nanoHUB session identifier
SESSIONDIR or SESSION_DIR	Path to session directory containing resources file

Output Variables (set by nanohub-gradio):

Variable	Description
DASH_REQUESTS_PATHNAME_PREFIX	Full weber proxy path for Dash requests
DASH_ROUTES_PATHNAME_PREFIX	Always set to /
DASH_HOST	Host address for Dash server
DASH_PORT	Port number for Dash server
DASH_BASE_PROXY	Base proxy URL (e.g., https://proxy.nanohub.org)

Additional Variables (set by start_dash):

Variable	Description
HOST	Host for the Dash server (used internally)
PORT	Port for the Dash server (used internally)
DASH_DEBUG	Debug mode flag
APP_NAME	Detected application name