Allow Vars in page metadata

news/6923.bugfix.md

@@ -0,0 +1 @@
+Allow State Vars for page titles and descriptions in `@rx.page` and compiled metadata.

reflex/app.py

@@ -1020,8 +1020,12 @@ def _prepare_page(
                 from reflex_components_core.el.elements import span
 
                 component = span("404: Page not found")
-            title = title or constants.Page404.TITLE
-            description = description or constants.Page404.DESCRIPTION
+            title = title if title is not None else constants.Page404.TITLE
+            description = (
+                description
+                if description is not None
+                else constants.Page404.DESCRIPTION
+            )
             image = image or constants.Page404.IMAGE
         else:
             if component is None:

reflex/compiler/utils.py

@@ -784,10 +784,10 @@ def get_memo_module_path(segments: tuple[str, ...]) -> str:
 
 def add_meta(
     page: Component,
-    title: str,
+    title: str | Var,
     image: str,
     meta: Sequence[Mapping[str, Any] | Component],
-    description: str | None = None,
+    description: str | Var | None = None,
 ) -> Component:
     """Add metadata to a page.
 
@@ -806,7 +806,7 @@ def add_meta(
     ]
 
     children: list[Any] = [Title.create(title)]
-    if description:
+    if description is not None:
         children.append(Description.create(content=description))
     children.append(Image.create(content=image))
 

reflex/page.py

@@ -12,13 +12,14 @@
     from typing import Any
 
     from reflex_base.event import EventType
+    from reflex_base.vars import Var
 
 
 def page(
     route: str | None = None,
-    title: str | None = None,
+    title: str | Var | None = None,
     image: str | None = None,
-    description: str | None = None,
+    description: str | Var | None = None,
     meta: list[Any] | None = None,
     script_tags: list[Any] | None = None,
     on_load: EventType[()] | None = None,
@@ -49,11 +50,11 @@ def decorator(render_fn: Callable):
         kwargs: dict[str, Any] = {}
         if route:
             kwargs["route"] = route
-        if title:
+        if title is not None:
             kwargs["title"] = title
         if image:
             kwargs["image"] = image
-        if description:
+        if description is not None:
             kwargs["description"] = description
         if meta:
             kwargs["meta"] = meta
@@ -75,9 +76,9 @@ class PageNamespace:
     def __new__(
         cls,
         route: str | None = None,
-        title: str | None = None,
+        title: str | Var | None = None,
         image: str | None = None,
-        description: str | None = None,
+        description: str | Var | None = None,
         meta: list[Any] | None = None,
         script_tags: list[Any] | None = None,
         on_load: EventType[()] | None = None,

tests/units/compiler/test_compiler.py

@@ -19,7 +19,7 @@
 from reflex_base.utils.imports import ImportVar, ParsedImportDict
 from reflex_base.vars.base import Var
 from reflex_base.vars.sequence import LiteralStringVar
-from reflex_components_core.base import document
+from reflex_components_core.base import Description, document
 from reflex_components_core.base.document import Links, Scripts
 from reflex_components_core.el.elements.metadata import Head, Link, Meta
 from reflex_components_core.el.elements.other import Html
@@ -617,6 +617,25 @@ def test_create_document_root():
     assert isinstance(root.children[0].children[5], Links)
 
 
+def test_add_meta_accepts_dynamic_description():
+    """Dynamic page descriptions should be represented as component Vars."""
+
+    class PageState(rx.State):
+        description: str = "Dynamic description"
+
+    page = rx.box()
+    utils.add_meta(
+        page,
+        title="title",
+        image="",
+        meta=(),
+        description=PageState.description,
+    )
+
+    assert isinstance(page.children[1], Description)
+    assert page.children[1].content is PageState.description
+
+
 def test_create_document_root_with_scripts():
     # Test with components.
     comps = [

tests/units/test_app.py

@@ -261,6 +261,24 @@ def test_add_page_default_route(
     assert app._pages.keys() == {"index", "about"}
 
 
+def test_prepare_404_page_preserves_dynamic_metadata():
+    """404 fallback defaults should not evaluate explicitly supplied Vars."""
+
+    class PageState(rx.State):
+        title: str = "Dynamic title"
+        description: str = "Dynamic description"
+
+    app = App()
+    prepared = app._prepare_page(
+        route=constants.Page404.SLUG,
+        title=PageState.title,
+        description=PageState.description,
+    )
+
+    assert prepared.page.title is PageState.title
+    assert prepared.page.description is PageState.description
+
+
 def test_add_page_set_route(app: App, index_page: ComponentCallable):
     """Test adding a page to an app.
 

tests/units/test_page.py

@@ -1,6 +1,6 @@
 from reflex_base.registry import RegistrationContext
 
-from reflex import text
+from reflex import State, text
 from reflex.page import page
 
 
@@ -22,6 +22,27 @@ def foo_():
     assert page_data == {}
 
 
+def test_page_decorator_accepts_state_metadata(
+    clean_registration_context: RegistrationContext,
+):
+    """State Vars should be preserved as page metadata without bool evaluation."""
+
+    class PageState(State):
+        title: str = "Dynamic title"
+        description: str = "Dynamic description"
+
+    def foo_():
+        return text("foo")
+
+    assert clean_registration_context.decorated_pages == []
+    page(title=PageState.title, description=PageState.description)(foo_)
+
+    assert len(clean_registration_context.decorated_pages) == 1
+    _, page_data = clean_registration_context.decorated_pages[0]
+    assert page_data["title"] is PageState.title
+    assert page_data["description"] is PageState.description
+
+
 def test_page_decorator_with_kwargs(
     clean_registration_context: RegistrationContext,
 ):