feat: config to customize bootstrap data overrides (apache#16386)

* feat: config to customize bootstrap data overrides

* comments

superset/config.py

@@ -428,6 +428,20 @@ def _try_json_readsha(filepath: str, length: int) -> Optional[str]:
 #     return feature_flags_dict
 GET_FEATURE_FLAGS_FUNC: Optional[Callable[[Dict[str, bool]], Dict[str, bool]]] = None
 
+# A function that expands/overrides the frontend `bootstrap_data.common` object.
+# Can be used to implement custom frontend functionality,
+# or dynamically change certain configs.
+#
+# Values in `bootstrap_data.common` should have these characteristics:
+# - They are not specific to a page the user is visiting
+# - They do not contain secrets
+#
+# Takes as a parameter the common bootstrap payload before transformations.
+# Returns a dict containing data that should be added or overridden to the payload.
+COMMON_BOOTSTRAP_OVERRIDES_FUNC: Callable[
+    [Dict[str, Any]], Dict[str, Any]
+] = lambda data: {}  # default: empty dict
+
 # EXTRA_CATEGORICAL_COLOR_SCHEMES is used for adding custom categorical color schemes
 # example code for "My custom warm to hot" color scheme
 # EXTRA_CATEGORICAL_COLOR_SCHEMES = [

superset/views/base.py

@@ -346,7 +346,7 @@ def common_bootstrap_payload() -> Dict[str, Any]:
     messages = get_flashed_messages(with_categories=True)
     locale = str(get_locale())
 
-    return {
+    bootstrap_data = {
         "flash_messages": messages,
         "conf": {k: conf.get(k) for k in FRONTEND_CONF_KEYS},
         "locale": locale,
@@ -357,6 +357,8 @@ def common_bootstrap_payload() -> Dict[str, Any]:
         "theme_overrides": conf["THEME_OVERRIDES"],
         "menu_data": menu_data(),
     }
+    bootstrap_data.update(conf["COMMON_BOOTSTRAP_OVERRIDES_FUNC"](bootstrap_data))
+    return bootstrap_data
 
 
 # pylint: disable=invalid-name