refactor: add missing exports, better error handling, and handle boolean query params (#1422)

src/django_components/__init__.py

@@ -34,7 +34,6 @@ from django_components.component_registry import (
     registry,
     all_registries,
 )
-from django_components.components import DynamicComponent
 from django_components.dependencies import DependenciesStrategy, render_dependencies
 from django_components.extension import (
     ComponentExtension,
@@ -47,6 +46,10 @@ from django_components.extension import (
     OnComponentClassDeletedContext,
     OnComponentInputContext,
     OnComponentDataContext,
+    OnComponentRenderedContext,
+    OnSlotRenderedContext,
+    OnTemplateCompiledContext,
+    OnTemplateLoadedContext,
 )
 from django_components.extensions.cache import ComponentCache
 from django_components.extensions.defaults import ComponentDefaults, Default
@@ -81,6 +84,9 @@ from django_components.util.loader import ComponentFileEntry, get_component_dirs
 from django_components.util.routing import URLRoute, URLRouteHandler
 from django_components.util.types import Empty
 
+# NOTE: Import built-in components last to avoid circular imports
+from django_components.components import DynamicComponent
+
 # isort: on
 
 
@@ -122,10 +128,14 @@ __all__ = [
     "OnComponentDataContext",
     "OnComponentInputContext",
     "OnComponentRegisteredContext",
+    "OnComponentRenderedContext",
     "OnComponentUnregisteredContext",
     "OnRegistryCreatedContext",
     "OnRegistryDeletedContext",
     "OnRenderGenerator",
+    "OnSlotRenderedContext",
+    "OnTemplateCompiledContext",
+    "OnTemplateLoadedContext",
     "ProvideNode",
     "RegistrySettings",
     "ShorthandComponentFormatter",

src/django_components/extensions/view.py

@@ -48,6 +48,12 @@ def get_component_url(
 
     `get_component_url()` optionally accepts `query` and `fragment` arguments.
 
+    **Query parameter handling:**
+
+    - `True` values are rendered as flag parameters without values (e.g., `?enabled`)
+    - `False` and `None` values are omitted from the URL
+    - Other values are rendered normally (e.g., `?foo=bar`)
+
     **Example:**
 
     ```py
@@ -60,10 +66,10 @@ def get_component_url(
     # Get the URL for the component
     url = get_component_url(
         MyComponent,
-        query={"foo": "bar"},
+        query={"foo": "bar", "enabled": True, "debug": False, "unused": None},
         fragment="baz",
     )
-    # /components/ext/view/components/c1ab2c3?foo=bar#baz
+    # /components/ext/view/components/c1ab2c3?foo=bar&enabled#baz
     ```
     """
     view_cls: Optional[Type[ComponentView]] = getattr(component, "View", None)

src/django_components/util/exception.py

@@ -20,20 +20,27 @@ def component_error_message(component_path: List[str]) -> Generator[None, None,
         components = getattr(err, "_components", [])
         components = err._components = [*component_path, *components]  # type: ignore[attr-defined]
 
-        # Access the exception's message, see https://stackoverflow.com/a/75549200/9788634
-        if len(err.args) and err.args[0] is not None:
-            if not components:
-                orig_msg = str(err.args[0])
-            else:
-                orig_msg = str(err.args[0]).split("\n", 1)[-1]
-        else:
-            orig_msg = str(err)
-
         # Format component path as
         # "MyPage > MyComponent > MyComponent(slot:content) > Base(slot:tab)"
         comp_path = " > ".join(components)
         prefix = f"An error occured while rendering components {comp_path}:\n"
 
+        # Access the exception's message, see https://stackoverflow.com/a/75549200/9788634
+        if len(err.args) and err.args[0] is not None:
+            orig_msg = str(err.args[0])
+            if components and "An error occured while rendering components" in orig_msg:
+                orig_msg = str(err.args[0]).split("\n", 1)[-1]
+        else:
+            # When the exception has no message, it may be that the exception
+            # does NOT rely on the `args` attribute. Such case is for example
+            # Pydantic exceptions.
+            #
+            # In this case, we still try to use the `args` attribute, but
+            # it's not guaranteed to work. So we also print out the component
+            # path ourselves.
+            print(prefix)  # noqa: T201
+            orig_msg = str(err)
+
         err.args = (prefix + orig_msg,)  # tuple of one
 
         # `from None` should still raise the original error, but without showing this

src/django_components/util/misc.py

@@ -162,12 +162,35 @@ def format_url(url: str, query: Optional[Dict] = None, fragment: Optional[str] =
     ```
 
     `query` and `fragment` are optional, and not applied if `None`.
+
+    Boolean `True` values in query parameters are rendered as flag parameters without values.
+
+    `False` and `None` values in query parameters are omitted.
+
+    ```py
+    url = format_url(
+        url="https://example.com",
+        query={"foo": "bar", "baz": None, "enabled": True, "debug": False},
+    )
+    # https://example.com?foo=bar&enabled
+    ```
     """
     parts = parse.urlsplit(url)
     fragment_enc = parse.quote(fragment or parts.fragment, safe="")
     base_qs = dict(parse.parse_qsl(parts.query))
-    merged = {**base_qs, **(query or {})}
-    encoded_qs = parse.urlencode(merged, safe="")
+    # Filter out `None` and `False` values
+    filtered_query = {k: v for k, v in (query or {}).items() if v is not None and v is not False}
+    merged = {**base_qs, **filtered_query}
+
+    # Handle boolean True values as flag parameters (no explicit value)
+    query_parts = []
+    for key, value in merged.items():
+        if value is True:
+            query_parts.append(parse.quote_plus(str(key)))
+        else:
+            query_parts.append(f"{parse.quote_plus(str(key))}={parse.quote_plus(str(value))}")
+
+    encoded_qs = "&".join(query_parts)
 
     return parse.urlunsplit(parts._replace(query=encoded_qs, fragment=fragment_enc))