Routing callback inputs

CHANGELOG.md

@@ -4,7 +4,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ## [UNRELEASED]
 
-## Fixed 
+## Fixed
 
 - [#2634](https://github.com/plotly/dash/pull/2634) Fix deprecation warning on pkg_resources, fix [#2631](https://github.com/plotly/dash/issues/2631)
 
@@ -25,6 +25,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ## Added
 
 - [#2630](https://github.com/plotly/dash/pull/2630) New layout hooks in the renderer
+- [#2647](https://github.com/plotly/dash/pull/2647) `routing_callback_inputs` allowing to pass more Input and/or State arguments to the pages routing callback
 
 
 ## [2.12.1] - 2023-08-16

dash/dash.py

@@ -16,7 +16,7 @@
 import base64
 import traceback
 from urllib.parse import urlparse
-from typing import Union
+from typing import Dict, Optional, Union
 
 import flask
 
@@ -29,8 +29,9 @@
 from .fingerprint import build_fingerprint, check_fingerprint
 from .resources import Scripts, Css
 from .dependencies import (
-    Output,
     Input,
+    Output,
+    State,
 )
 from .development.base_component import ComponentRegistry
 from .exceptions import (
@@ -347,6 +348,12 @@ class Dash:
     :param hooks: Extend Dash renderer functionality by passing a dictionary of
     javascript functions. To hook into the layout, use dict keys "layout_pre" and
     "layout_post". To hook into the callbacks, use keys "request_pre" and "request_post"
+
+    :param routing_callback_inputs: When using Dash pages (use_pages=True), allows to
+    add new States to the routing callback, to pass additional data to the layout
+    functions. The syntax for this parameter is a dict of State objects:
+    `routing_callback_inputs={"language": Input("language", "value")}`
+    NOTE: the keys "pathname_" and "search_" are reserved for internal use.
     """
 
     _plotlyjs_url: str
@@ -384,6 +391,7 @@ def __init__(  # pylint: disable=too-many-statements
         background_callback_manager=None,
         add_log_handler=True,
         hooks: Union[RendererHooks, None] = None,
+        routing_callback_inputs: Optional[Dict[str, Union[Input, State]]] = None,
         **obsolete,
     ):
         _validate.check_obsolete(obsolete)
@@ -461,6 +469,7 @@ def __init__(  # pylint: disable=too-many-statements
 
         self.pages_folder = str(pages_folder)
         self.use_pages = (pages_folder != "pages") if use_pages is None else use_pages
+        self.routing_callback_inputs = routing_callback_inputs or {}
 
         # keep title as a class property for backwards compatibility
         self.title = title
@@ -2078,21 +2087,28 @@ def router():
                 return
             self._got_first_request["pages"] = True
 
+            inputs = {
+                "pathname_": Input(_ID_LOCATION, "pathname"),
+                "search_": Input(_ID_LOCATION, "search"),
+            }
+            inputs.update(self.routing_callback_inputs)
+
             @self.callback(
                 Output(_ID_CONTENT, "children"),
                 Output(_ID_STORE, "data"),
-                Input(_ID_LOCATION, "pathname"),
-                Input(_ID_LOCATION, "search"),
+                inputs=inputs,
                 prevent_initial_call=True,
             )
-            def update(pathname, search):
+            def update(pathname_, search_, **states):
                 """
                 Updates dash.page_container layout on page navigation.
                 Updates the stored page title which will trigger the clientside callback to update the app title
                 """
 
-                query_parameters = _parse_query_string(search)
-                page, path_variables = _path_to_page(self.strip_relative_path(pathname))
+                query_parameters = _parse_query_string(search_)
+                page, path_variables = _path_to_page(
+                    self.strip_relative_path(pathname_)
+                )
 
                 # get layout
                 if page == {}:
@@ -2110,9 +2126,9 @@ def update(pathname, search):
 
                 if callable(layout):
                     layout = (
-                        layout(**path_variables, **query_parameters)
+                        layout(**path_variables, **query_parameters, **states)
                         if path_variables
-                        else layout(**query_parameters)
+                        else layout(**query_parameters, **states)
                     )
                 if callable(title):
                     title = title(**path_variables) if path_variables else title()

requires-install.txt

@@ -5,6 +5,7 @@ dash_html_components==2.0.0
 dash_core_components==2.0.0
 dash_table==5.0.0
 importlib-metadata==4.8.3;python_version<"3.7"
+importlib-metadata;python_version>="3.7"
 contextvars==2.4;python_version<"3.7"
 typing_extensions>=4.1.1
 requests

tests/integration/multi_page/test_pages_layout.py

@@ -1,6 +1,7 @@
 import pytest
 import dash
-from dash import Dash, dcc, html
+from dash import Dash, Input, State, dcc, html
+from dash.dash import _ID_LOCATION
 from dash.exceptions import NoLayoutException
 
 
@@ -59,38 +60,33 @@ def test_pala001_layout(dash_duo, clear_pages_state):
         assert dash_duo.driver.title == page["title"], "check that page title updates"
 
     # test redirects
-    dash_duo.wait_for_page(url=f"http://localhost:{dash_duo.server.port}/v2")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/v2")
     dash_duo.wait_for_text_to_equal("#text_redirect", "text for redirect")
-    dash_duo.wait_for_page(url=f"http://localhost:{dash_duo.server.port}/old-home-page")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/old-home-page")
     dash_duo.wait_for_text_to_equal("#text_redirect", "text for redirect")
-    assert (
-        dash_duo.driver.current_url
-        == f"http://localhost:{dash_duo.server.port}/redirect"
-    )
+    assert dash_duo.driver.current_url == f"{dash_duo.server_url}/redirect"
 
     # test redirect with button and user defined dcc.Location
     # note:  dcc.Location must be defined in app.py
-    dash_duo.wait_for_page(url=f"http://localhost:{dash_duo.server.port}/page1")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/page1")
     dash_duo.find_element("#btn1").click()
     dash_duo.wait_for_text_to_equal("#text_page2", "text for page2")
 
     # test query strings
-    dash_duo.wait_for_page(
-        url=f"http://localhost:{dash_duo.server.port}/query-string?velocity=10"
-    )
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/query-string?velocity=10")
     assert (
         dash_duo.find_element("#velocity").get_attribute("value") == "10"
     ), "query string passed to layout"
 
     # test path variables
-    dash_duo.wait_for_page(url=f"http://localhost:{dash_duo.server.port}/a/none/b/none")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/a/none/b/none")
     dash_duo.wait_for_text_to_equal("#path_vars", "variables from pathname:none none")
 
-    dash_duo.wait_for_page(url=f"http://localhost:{dash_duo.server.port}/a/var1/b/var2")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/a/var1/b/var2")
     dash_duo.wait_for_text_to_equal("#path_vars", "variables from pathname:var1 var2")
 
     # test page not found
-    dash_duo.wait_for_page(url=f"http://localhost:{dash_duo.server.port}/find_me")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/find_me")
     dash_duo.wait_for_text_to_equal("#text_not_found_404", "text for not_found_404")
 
     # test `validation_layout` exists when suppress_callback_exceptions=False`
@@ -121,20 +117,20 @@ def test_pala002_meta_tags_default(dash_duo, clear_pages_state):
         {"property": "twitter:card", "content": "summary_large_image"},
         {
             "property": "twitter:url",
-            "content": f"http://localhost:{dash_duo.server.port}/",
+            "content": f"{dash_duo.server_url}/",
         },
         {"property": "twitter:title", "content": "Multi layout2"},
         {"property": "twitter:description", "content": ""},
         {
             "property": "twitter:image",
-            "content": f"http://localhost:{dash_duo.server.port}/assets/app.jpeg",
+            "content": f"{dash_duo.server_url}/assets/app.jpeg",
         },
         {"property": "og:title", "content": "Multi layout2"},
         {"property": "og:type", "content": "website"},
         {"property": "og:description", "content": ""},
         {
             "property": "og:image",
-            "content": f"http://localhost:{dash_duo.server.port}/assets/app.jpeg",
+            "content": f"{dash_duo.server_url}/assets/app.jpeg",
         },
     ]
 
@@ -149,7 +145,7 @@ def test_pala003_meta_tags_custom(dash_duo, clear_pages_state):
         {"property": "twitter:card", "content": "summary_large_image"},
         {
             "property": "twitter:url",
-            "content": f"http://localhost:{dash_duo.server.port}/",
+            "content": f"{dash_duo.server_url}/",
         },
         {"property": "twitter:title", "content": "Supplied Title"},
         {
@@ -158,14 +154,14 @@ def test_pala003_meta_tags_custom(dash_duo, clear_pages_state):
         },
         {
             "property": "twitter:image",
-            "content": f"http://localhost:{dash_duo.server.port}/assets/birds.jpeg",
+            "content": f"{dash_duo.server_url}/assets/birds.jpeg",
         },
         {"property": "og:title", "content": "Supplied Title"},
         {"property": "og:type", "content": "website"},
         {"property": "og:description", "content": "This is the supplied description"},
         {
             "property": "og:image",
-            "content": f"http://localhost:{dash_duo.server.port}/assets/birds.jpeg",
+            "content": f"{dash_duo.server_url}/assets/birds.jpeg",
         },
     ]
 
@@ -179,3 +175,63 @@ def test_pala004_no_layout_exception(clear_pages_state):
         Dash(__name__, use_pages=True, pages_folder="pages_error")
 
     assert error_msg in err.value.args[0]
+
+
+def get_routing_inputs_app():
+    app = Dash(
+        __name__,
+        use_pages=True,
+        routing_callback_inputs={
+            "hash": State(_ID_LOCATION, "hash"),
+            "language": Input("language", "value"),
+        },
+    )
+    # Page with layout from a variable: should render and not be impacted
+    # by routing callback inputs
+    dash.register_page(
+        "home",
+        layout=html.Div("Home", id="contents"),
+        path="/",
+    )
+
+    # Page with a layout function, should see the routing callback inputs
+    # as keyword arguments
+    def layout1(hash: str = None, language: str = "en", **kwargs):
+        translations = {
+            "en": "Hash says: {}",
+            "fr": "Le hash dit: {}",
+        }
+        return html.Div(translations[language].format(hash), id="contents")
+
+    dash.register_page(
+        "function_layout",
+        path="/function-layout",
+        layout=layout1,
+    )
+    app.layout = html.Div(
+        [
+            dcc.Dropdown(id="language", options=["en", "fr"], value="en"),
+            dash.page_container,
+        ]
+    )
+    return app
+
+
+def test_pala005_routing_inputs(dash_duo, clear_pages_state):
+    dash_duo.start_server(get_routing_inputs_app())
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}#123")
+    dash_duo.wait_for_text_to_equal("#contents", "Home")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/")
+    dash_duo.wait_for_text_to_equal("#contents", "Home")
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/function-layout")
+    dash_duo.wait_for_text_to_equal("#contents", "Hash says:")
+    # hash is a State therefore navigating to the same page with hash will not
+    # re-render the layout function
+    dash_duo.wait_for_page(url=f"{dash_duo.server_url}/function-layout#123")
+    dash_duo.wait_for_text_to_equal("#contents", "Hash says:")
+    # Refreshing the page re-runs the layout function
+    dash_duo.driver.refresh()
+    dash_duo.wait_for_text_to_equal("#contents", "Hash says: #123")
+    # Changing the language Input re-runs the layout function
+    dash_duo.select_dcc_dropdown("#language", "fr")
+    dash_duo.wait_for_text_to_equal("#contents", "Le hash dit: #123")