Merge pull request #3051 from plotly/fix/bg-cookies

Add request data to callback_context

Author: T4rk1n

CHANGELOG.md

@@ -14,6 +14,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - [#3034](https://github.com/plotly/dash/pull/3034) Remove whitespace from `metadata.json` files to reduce package size.
 - [#3009](https://github.com/plotly/dash/pull/3009) Performance improvement on (pattern-matching) callbacks.
 - [3028](https://github.com/plotly/dash/pull/3028) Fix jupyterlab v4 support.
+- [#3051](https://github.com/plotly/dash/pull/3051) Add missing request data to callback context. Fix [#2235](https://github.com/plotly/dash/issues/2235).
 
 ## [2.18.1] - 2024-09-12
 

dash/_callback.py

@@ -409,23 +409,16 @@ def add_context(*args, **kwargs):
 
                     job_fn = callback_manager.func_registry.get(long_key)
 
+                    ctx_value = AttributeDict(**context_value.get())
+                    ctx_value.ignore_register_page = True
+                    ctx_value.pop("background_callback_manager")
+                    ctx_value.pop("dash_response")
+
                     job = callback_manager.call_job_fn(
                         cache_key,
                         job_fn,
                         func_args if func_args else func_kwargs,
-                        AttributeDict(
-                            args_grouping=callback_ctx.args_grouping,
-                            using_args_grouping=callback_ctx.using_args_grouping,
-                            outputs_grouping=callback_ctx.outputs_grouping,
-                            using_outputs_grouping=callback_ctx.using_outputs_grouping,
-                            inputs_list=callback_ctx.inputs_list,
-                            states_list=callback_ctx.states_list,
-                            outputs_list=callback_ctx.outputs_list,
-                            input_values=callback_ctx.input_values,
-                            state_values=callback_ctx.state_values,
-                            triggered_inputs=callback_ctx.triggered_inputs,
-                            ignore_register_page=True,
-                        ),
+                        ctx_value,
                     )
 
                     data = {

dash/_callback_context.py

@@ -30,6 +30,10 @@ def _get_context_value():
     return context_value.get()
 
 
+def _get_from_context(key, default):
+    return getattr(_get_context_value(), key, default)
+
+
 class FalsyList(list):
     def __bool__(self):
         # for Python 3
@@ -258,6 +262,48 @@ def set_props(self, component_id: typing.Union[str, dict], props: dict):
         else:
             ctx_value.updated_props[_id] = props
 
+    @property
+    @has_context
+    def cookies(self):
+        """
+        Get the cookies for the current callback.
+        Works with background callbacks.
+        """
+        return _get_from_context("cookies", {})
+
+    @property
+    @has_context
+    def headers(self):
+        """
+        Get the original headers for the current callback.
+        Works with background callbacks.
+        """
+        return _get_from_context("headers", {})
+
+    @property
+    @has_context
+    def path(self):
+        """
+        Path of the callback request with the query parameters.
+        """
+        return _get_from_context("path", "")
+
+    @property
+    @has_context
+    def remote(self):
+        """
+        Remote addr of the callback request.
+        """
+        return _get_from_context("remote", "")
+
+    @property
+    @has_context
+    def origin(self):
+        """
+        Origin of the callback request.
+        """
+        return _get_from_context("origin", "")
+
 
 callback_context = CallbackContext()
 

dash/dash.py

@@ -1360,6 +1360,12 @@ def dispatch(self):
                 g.using_outputs_grouping = []
             g.updated_props = {}
 
+            g.cookies = dict(**flask.request.cookies)
+            g.headers = dict(**flask.request.headers)
+            g.path = flask.request.full_path
+            g.remote = flask.request.remote_addr
+            g.origin = flask.request.origin
+
         except KeyError as missing_callback_function:
             msg = f"Callback function not found for output '{output}', perhaps you forgot to prepend the '@'?"
             raise KeyError(msg) from missing_callback_function

tests/integration/long_callback/app_ctx_cookies.py

@@ -0,0 +1,43 @@
+from dash import Dash, Input, Output, html, callback, ctx
+
+from tests.integration.long_callback.utils import get_long_callback_manager
+
+long_callback_manager = get_long_callback_manager()
+handle = long_callback_manager.handle
+
+app = Dash(__name__, background_callback_manager=long_callback_manager)
+
+app.layout = html.Div(
+    [
+        html.Button("set-cookies", id="set-cookies"),
+        html.Button("use-cookies", id="use-cookies"),
+        html.Div(id="intermediate"),
+        html.Div("output", id="output"),
+    ]
+)
+app.test_lock = lock = long_callback_manager.test_lock
+
+
+@callback(
+    Output("intermediate", "children"),
+    Input("set-cookies", "n_clicks"),
+    prevent_initial_call=True,
+)
+def set_cookies(_):
+    ctx.response.set_cookie("bg-cookie", "cookie-value")
+    return "ok"
+
+
+@callback(
+    Output("output", "children"),
+    Input("use-cookies", "n_clicks"),
+    prevent_initial_call=True,
+    background=True,
+)
+def use_cookies(_):
+    value = ctx.cookies.get("bg-cookie")
+    return value
+
+
+if __name__ == "__main__":
+    app.run(debug=True)

tests/integration/long_callback/test_ctx_cookies.py

@@ -0,0 +1,12 @@
+from tests.integration.long_callback.utils import setup_long_callback_app
+
+
+def test_lcbc019_ctx_cookies(dash_duo, manager):
+    with setup_long_callback_app(manager, "app_ctx_cookies") as app:
+        dash_duo.start_server(app)
+
+        dash_duo.find_element("#set-cookies").click()
+        dash_duo.wait_for_contains_text("#intermediate", "ok")
+
+        dash_duo.find_element("#use-cookies").click()
+        dash_duo.wait_for_contains_text("#output", "cookie-value")