Why does dash return a status code of 200 when a page is not found

Dash Python
3

Thank you for the response but that option only inserts a layout when there is a “404” into dash.page_container and keeps the default layout. I really just want to return a static html file. I will probably end up going with something like

@app.server.before_request
def override_dash_404():
    """ Ensure unknown paths return a proper 404 page. """

    # Store the stripped request path once
    requested_path = flask.request.path.strip("/")

    # Known Dash and Flask routes
    dash_routes = {page["path"].strip("/") for page in dash.page_registry.values()}
    flask_routes = {rule.rule.strip("/") for rule in app.server.url_map.iter_rules()}

    # ✅ Allow valid Dash routes
    if requested_path in dash_routes:
        return  # Let Dash handle it

    # ✅ Allow valid Flask routes
    if requested_path in flask_routes:
        return  # Let Flask handle it

    # ✅ Allow Dash-internal API calls (updates, assets, favicon, etc.)
    if flask.request.path.startswith(("/_dash", "/assets/", "/favicon.ico")):
        return  # Let Dash handle it

    # ❌ Everything else gets a real 404 error
    flask.abort(404)  # This ensures Flask's real 404 handling takes over

@app.server.errorhandler(404)
def page_not_found(error):
    """ Serve a proper 404 page instead of Dash's fake 404 """
    return flask.render_template("404.html"), 404
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