feat: redirect 404/500 to static pages (#14677)

* feat: redirect 404/500 to static pages

* Show pages only on html requests

superset-frontend/src/assets/staticPages/404.html

@@ -94,7 +94,7 @@
       <section>
         <h1>Page not found</h1>
         <p>
-          Sorry, we cannot find t he page you are looking for. You may have
+          Sorry, we cannot find the page you are looking for. You may have
           mistyped the address or the page may have moved.
         </p>
         <a href="/" class="button">Back to home</a>

superset/views/base.py

@@ -385,6 +385,13 @@ def refresh_csrf_token(ex: CSRFError) -> FlaskResponse:
 @superset_app.errorhandler(HTTPException)
 def show_http_exception(ex: HTTPException) -> FlaskResponse:
     logger.warning(ex)
+    if (
+        "text/html" in request.accept_mimetypes
+        and not config["DEBUG"]
+        and ex.code in {404, 500}
+    ):
+        return redirect(f"/static/assets/{ex.code}.html")
+
     return json_errors_response(
         errors=[
             SupersetError(