Method start

dash/testing/application_runners.py:241–272

(self, app, start_timeout=3, **kwargs)

    # pylint: disable=arguments-differ
    def start(self, app, start_timeout=3, **kwargs):
        self.port = kwargs.get("port", 8050)

        def target():
            app.scripts.config.serve_locally = True
            app.css.config.serve_locally = True

            options = kwargs.copy()

            try:
                module = app.server.__class__.__module__
                # FastAPI support
                if module.startswith("fastapi"):
                    app.run(**options)
                # Quart support (ASGI - runs its own async event loop)
                elif module.startswith("quart"):
                    app.run(**options)
                # Flask fallback (WSGI - needs threaded mode)
                else:
                    app.run(threaded=True, **options)
            except SystemExit:
                logger.info("Server stopped")
                raise
            except Exception as error:
                logger.exception(error)
                raise error

        self.proc = multiprocess.Process(target=target)  # type: ignore[reportAttributeAccessIssue]; pylint: disable=not-callable
        self.proc.start()

        wait.until(lambda: self.accessible(self.url), timeout=start_timeout)
        self.started = True

    def stop(self):
        process = psutil.Process(self.proc.pid)  # type: ignore[reportOptionalMemberAccess]