Merge pull request #2265 from AnnMarieW/remove_before_first_request

removed deprecated before_first_request

Author: alexcjohnson

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Fixed
 
+- [#2265](https://github.com/plotly/dash/pull/2265) Removed deprecated `before_first_request` as reported in [#2177](https://github.com/plotly/dash/issues/2177).
 - [#2257](https://github.com/plotly/dash/pull/2257) Fix tuple types in the TypeScript component generator.
 
 ## [2.6.2] - 2022-09-23

dash/_pages.py

@@ -5,11 +5,13 @@
 from urllib.parse import parse_qs
 from fnmatch import fnmatch
 import re
+import flask
 
 from . import _validate
 from ._utils import AttributeDict
 from ._get_paths import get_relative_path
 from ._callback_context import context_value
+from ._get_app import get_app
 
 
 CONFIG = AttributeDict()
@@ -118,6 +120,25 @@ def _parse_path_variables(pathname, path_template):
     return dict(zip(var_names, variables))
 
 
+def _create_redirect_function(redirect_to):
+    def redirect():
+        return flask.redirect(redirect_to, code=301)
+
+    return redirect
+
+
+def _set_redirect(redirect_from, path):
+    app = get_app()
+    if redirect_from and len(redirect_from):
+        for redirect in redirect_from:
+            fullname = app.get_relative_path(redirect)
+            app.server.add_url_rule(
+                fullname,
+                fullname,
+                _create_redirect_function(app.get_relative_path(path)),
+            )
+
+
 def register_page(
     module,
     path=None,
@@ -280,7 +301,7 @@ def register_page(
         image=(image if image is not None else _infer_image(module)),
         image_url=image_url,
     )
-    page.update(redirect_from=redirect_from)
+    page.update(redirect_from=_set_redirect(redirect_from, page["path"]))
 
     PAGE_REGISTRY[module] = page
 

dash/dash.py

@@ -497,6 +497,9 @@ def __init__(  # pylint: disable=too-many-statements
             for plugin in plugins:
                 plugin.plug(self)
 
+        # tracks internally if a function already handled at least one request.
+        self._got_first_request = {"pages": False, "setup_server": False}
+
         if self.server is not None:
             self.init_app()
 
@@ -542,7 +545,7 @@ def _handle_error(_):
             """Handle a halted callback and return an empty 204 response."""
             return "", 204
 
-        self.server.before_first_request(self._setup_server)
+        self.server.before_request(self._setup_server)
 
         # add a handler for components suites errors to return 404
         self.server.errorhandler(InvalidResourceError)(self._invalid_resources_handler)
@@ -1271,6 +1274,10 @@ def dispatch(self):
         return response
 
     def _setup_server(self):
+        if self._got_first_request["setup_server"]:
+            return
+        self._got_first_request["setup_server"] = True
+
         # Apply _force_eager_loading overrides from modules
         eager_loading = self.config.eager_loading
         for module_name in ComponentRegistry.registry:
@@ -2027,8 +2034,12 @@ def enable_pages(self):
         if self.pages_folder:
             self._import_layouts_from_pages()
 
-        @self.server.before_first_request
+        @self.server.before_request
         def router():
+            if self._got_first_request["pages"]:
+                return
+            self._got_first_request["pages"] = True
+
             @self.callback(
                 Output(_ID_CONTENT, "children"),
                 Output(_ID_STORE, "data"),
@@ -2107,24 +2118,6 @@ def update(pathname, search):
                 Input(_ID_STORE, "data"),
             )
 
-            def create_redirect_function(redirect_to):
-                def redirect():
-                    return flask.redirect(redirect_to, code=301)
-
-                return redirect
-
-            # Set redirects
-            for module in _pages.PAGE_REGISTRY:
-                page = _pages.PAGE_REGISTRY[module]
-                if page["redirect_from"] and len(page["redirect_from"]):
-                    for redirect in page["redirect_from"]:
-                        fullname = self.get_relative_path(redirect)
-                        self.server.add_url_rule(
-                            fullname,
-                            fullname,
-                            create_redirect_function(page["relative_path"]),
-                        )
-
     def run_server(self, *args, **kwargs):
         """`run_server` is a deprecated alias of `run` and may be removed in a
         future version. We recommend using `app.run` instead.