Implementation:AUTOMATIC1111 Stable diffusion webui Webui Entry Point

Knowledge Sources	AUTOMATIC1111_Stable_diffusion_webui
Domains	Application Entry Point, Server Lifecycle
Last Updated	2025-05-15 00:00 GMT

Overview

Serves as the main entry point for the Stable Diffusion web UI application, orchestrating initialization, server launch, API setup, and the restart/stop lifecycle loop.

Description

The webui.py file is the primary entry point invoked to start the application. It begins by recording launcher timing, running imports and version checks through the initialize module, and then dispatches to either api_only() or webui() mode based on the --nowebui flag.

api_only() mode: Creates a bare FastAPI application without the Gradio UI. It initializes the application, sets up middleware, creates the API via create_api(), fires before_ui_callback and app_started_callback script callbacks, and launches the API server on the configured host/port.

webui() mode: Runs the full web UI in a restart-capable loop. Each iteration:

1. Optionally cleans the temp directory.
2. Fires before_ui_callback script callbacks.
3. Creates the Gradio UI via ui.create_ui().
4. Configures Gradio queue (default concurrency 64).
5. Launches the Gradio server with SSL, auth, auto-launch browser, and CORS security settings.
6. Removes the default overly-permissive CORS middleware as a security measure (suggested by RyotaK).
7. Sets up middleware, progress API, UI API, optional REST API, and extra networks pages.
8. Fires app_started_callback and records startup timing.
9. Enters a command wait loop, polling shared.state.wait_for_server_command() every 5 seconds.
10. On "stop", closes Gradio and exits. On "restart", closes Gradio, resets timers, fires reload/unload callbacks, and reinitializes with reloaded script modules before looping.

The create_api(app) helper creates an Api instance with the shared queue lock.

Usage

This file is the application entry point. Run it directly with python webui.py or via the launcher scripts. It should not typically be imported by other modules.

Code Reference

Source Location

• Repository: AUTOMATIC1111_Stable_diffusion_webui
• File: webui.py
• Lines: 1-162

Signature

def create_api(app: FastAPI) -> Api
def api_only() -> None
def webui() -> None

# Entry point
if __name__ == "__main__":
    if cmd_opts.nowebui:
        api_only()
    else:
        webui()

Import

# This is an entry point script, not typically imported.
# To run:
# python webui.py
# python webui.py --nowebui  # API-only mode

I/O Contract

Inputs

Name	Type	Required	Description
cmd_opts.nowebui	bool	No	If True, runs in API-only mode without the Gradio UI.
cmd_opts.api	bool	No	If True, enables the REST API alongside the Gradio UI.
cmd_opts.port	int	No	Server port; defaults to 7861 for API-only mode.
cmd_opts.share	bool	No	Whether to create a public Gradio share link.
cmd_opts.tls_keyfile	str	No	Path to TLS key file for HTTPS.
cmd_opts.tls_certfile	str	No	Path to TLS certificate file for HTTPS.
cmd_opts.gradio_auth	str	No	Gradio authentication credentials.
cmd_opts.subpath	str	No	URL subpath for reverse proxy configurations.

Outputs

Name	Type	Description
(server)	None	Launches the HTTP server; blocks until stop or keyboard interrupt.
startup_timer.summary()	str	Printed startup timing summary.

Usage Examples

# Standard launch (from command line)
# python webui.py

# API-only mode
# python webui.py --nowebui --port 7861

# With API enabled alongside UI
# python webui.py --api

# The webui() function loop handles restarts internally:
# - User clicks "Reload UI" in settings
# - shared.state.server_command is set to "restart"
# - Loop closes Gradio, reloads scripts, and relaunches

Related Pages

• Principle:AUTOMATIC1111_Stable_diffusion_webui_Application_Lifecycle