diff --git a/src/django_components/component.py b/src/django_components/component.py
index 46194f75..f1616653 100644
--- a/src/django_components/component.py
+++ b/src/django_components/component.py
@@ -20,12 +20,7 @@ from django.views import View
# way the two modules depend on one another.
from django_components.component_registry import registry # NOQA
from django_components.component_registry import AlreadyRegistered, ComponentRegistry, NotRegistered, register # NOQA
-from django_components.context import (
- capture_root_context,
- get_root_context,
- set_root_context,
- set_slot_component_association,
-)
+from django_components.context import make_isolated_context_copy, prepare_context, set_slot_component_association
from django_components.logger import logger, trace_msg
from django_components.middleware import is_dependency_middleware_active
from django_components.node import walk_nodelist
@@ -268,6 +263,7 @@ class Component(View, metaclass=SimplifiedInterfaceMediaDefiningClass):
# NOTE: This if/else is important to avoid nested Contexts,
# See https://github.com/EmilStenstrom/django-components/issues/414
context = context_data if isinstance(context_data, Context) else Context(context_data)
+ prepare_context(context, outer_context=self.outer_context or Context())
template = self.get_template(context)
# Associate the slots with this component for this context
@@ -347,10 +343,6 @@ class ComponentNode(Node):
resolved_component_name = self.name_fexp.resolve(context)
component_cls: Type[Component] = registry.get(resolved_component_name)
- # If this is the outer-/top-most component node, then save the outer context,
- # so it can be used by nested Slots.
- capture_root_context(context)
-
# Resolve FilterExpressions and Variables that were passed as args to the
# component, then call component's context method
# to get values to insert into the context
@@ -380,12 +372,7 @@ class ComponentNode(Node):
# Prevent outer context from leaking into the template of the component
if self.isolated_context:
- # Even if contexts are isolated, we still need to pass down the
- # original context so variables in slots can be rendered using
- # the original context.
- root_ctx = get_root_context(context)
- context = context.new()
- set_root_context(context, root_ctx)
+ context = make_isolated_context_copy(context)
with context.update(component_context):
rendered_component = component.render(context)
diff --git a/src/django_components/context.py b/src/django_components/context.py
index f3d92662..a7d91900 100644
--- a/src/django_components/context.py
+++ b/src/django_components/context.py
@@ -5,22 +5,65 @@ pass data across components, nodes, slots, and contexts.
You can think of the Context as our storage system.
"""
-from copy import copy
from typing import TYPE_CHECKING, Optional
from django.template import Context
from django_components.logger import trace_msg
+from django_components.utils import find_last_index
if TYPE_CHECKING:
from django_components.slots import FillContent
_FILLED_SLOTS_CONTENT_CONTEXT_KEY = "_DJANGO_COMPONENTS_FILLED_SLOTS"
-_OUTER_CONTEXT_CONTEXT_KEY = "_DJANGO_COMPONENTS_OUTER_CONTEXT"
+_OUTER_ROOT_CTX_CONTEXT_KEY = "_DJANGO_COMPONENTS_OUTER_ROOT_CTX"
_SLOT_COMPONENT_ASSOC_KEY = "_DJANGO_COMPONENTS_SLOT_COMP_ASSOC"
+def prepare_context(context: Context, outer_context: Optional[Context]) -> None:
+ """Initialize the internal context state."""
+ # This is supposed to run ALWAYS at Component.render
+ if outer_context is not None:
+ set_outer_root_context(context, outer_context)
+
+ # Initialize mapping dicts within this rendering run.
+ # This is shared across the whole render chain, thus we set it only once.
+ if _SLOT_COMPONENT_ASSOC_KEY not in context:
+ context[_SLOT_COMPONENT_ASSOC_KEY] = {}
+ if _FILLED_SLOTS_CONTENT_CONTEXT_KEY not in context:
+ context[_FILLED_SLOTS_CONTENT_CONTEXT_KEY] = {}
+
+ # If we're inside a forloop, we need to make a disposable copy of slot -> comp
+ # mapping, which can be modified in the loop. We do so by copying it onto the latest
+ # context layer.
+ #
+ # This is necessary, because otherwise if we have a nested loop with a same
+ # component used recursively, the inner slot -> comp mapping would leak into the outer.
+ #
+ # NOTE: If you ever need to debug this, insert a print/debug statement into
+ # `django.template.defaulttags.ForNode.render` to inspect the context object
+ # inside the for loop.
+ if "forloop" in context:
+ context.dicts[-1][_SLOT_COMPONENT_ASSOC_KEY] = context[_SLOT_COMPONENT_ASSOC_KEY].copy()
+
+
+def make_isolated_context_copy(context: Context) -> Context:
+ # Even if contexts are isolated, we still need to pass down the
+ # metadata so variables in slots can be rendered using the correct context.
+ root_ctx = get_outer_root_context(context)
+ slot_assoc = context.get(_SLOT_COMPONENT_ASSOC_KEY, {})
+ slot_fills = context.get(_FILLED_SLOTS_CONTENT_CONTEXT_KEY, {})
+
+ context_copy = context.new()
+ context_copy[_SLOT_COMPONENT_ASSOC_KEY] = slot_assoc
+ context_copy[_FILLED_SLOTS_CONTENT_CONTEXT_KEY] = slot_fills
+ set_outer_root_context(context_copy, root_ctx)
+ copy_forloop_context(context, context_copy)
+
+ return context_copy
+
+
def get_slot_fill(context: Context, component_id: str, slot_name: str) -> Optional["FillContent"]:
"""
Use this function to obtain a slot fill from the current context.
@@ -28,8 +71,8 @@ def get_slot_fill(context: Context, component_id: str, slot_name: str) -> Option
See `set_slot_fill` for more details.
"""
trace_msg("GET", "FILL", slot_name, component_id)
- slot_key = (_FILLED_SLOTS_CONTENT_CONTEXT_KEY, component_id, slot_name)
- return context.get(slot_key, None)
+ slot_key = f"{component_id}__{slot_name}"
+ return context[_FILLED_SLOTS_CONTENT_CONTEXT_KEY].get(slot_key, None)
def set_slot_fill(context: Context, component_id: str, slot_name: str, value: "FillContent") -> None:
@@ -38,77 +81,82 @@ def set_slot_fill(context: Context, component_id: str, slot_name: str, value: "F
Note that we make use of the fact that Django's Context is a stack - we can push and pop
extra contexts on top others.
-
- For the slot fills to be pushed/popped wth stack layer, they need to have keys defined
- directly on the Context object.
"""
trace_msg("SET", "FILL", slot_name, component_id)
- slot_key = (_FILLED_SLOTS_CONTENT_CONTEXT_KEY, component_id, slot_name)
- context[slot_key] = value
+ slot_key = f"{component_id}__{slot_name}"
+ context[_FILLED_SLOTS_CONTENT_CONTEXT_KEY][slot_key] = value
-def get_root_context(context: Context) -> Optional[Context]:
+def get_outer_root_context(context: Context) -> Optional[Context]:
"""
- Use this function to get the root context.
+ Use this function to get the outer root context.
- Root context is the top-most context, AKA the context that was passed to
- the initial `Template.render()`.
- We pass through the root context to allow configure how slot fills should be rendered.
-
- See the `SLOT_CONTEXT_BEHAVIOR` setting.
+ See `set_outer_root_context` for more details.
"""
- return context.get(_OUTER_CONTEXT_CONTEXT_KEY)
+ return context.get(_OUTER_ROOT_CTX_CONTEXT_KEY)
-def set_root_context(context: Context, root_ctx: Context) -> None:
+def set_outer_root_context(context: Context, outer_ctx: Optional[Context]) -> None:
"""
- Use this function to set the root context.
+ Use this function to set the outer root context.
- Root context is the top-most context, AKA the context that was passed to
- the initial `Template.render()`.
- We pass through the root context to allow configure how slot fills should be rendered.
+ When we consider a component's template, then outer context is the context
+ that was available just outside of the component's template (AKA it was in
+ the PARENT template).
- See the `SLOT_CONTEXT_BEHAVIOR` setting.
+ Once we have the outer context, next we get the outer ROOT context. This is
+ the context that was available at the top level of the PARENT template.
+
+ We pass through this context to allow to configure how slot fills should be
+ rendered using the `SLOT_CONTEXT_BEHAVIOR` setting.
"""
- context.push({_OUTER_CONTEXT_CONTEXT_KEY: root_ctx})
+ if outer_ctx and len(outer_ctx.dicts) > 1:
+ outer_root_context: Context = outer_ctx.new()
+ # NOTE_1:
+ # - Index 0 are the defaults set in BaseContext
+ # - Index 1 is the context generated by `Component.get_context_data`
+ # of the parent's component
+ # - All later indices (2, 3, ...) are extra layers added by the rendering
+ # logic (each Node usually adds it's own context layer)
+ outer_root_context.push(outer_ctx.dicts[1])
+ else:
+ outer_root_context = Context()
+
+ # Include the mappings.
+ if _SLOT_COMPONENT_ASSOC_KEY in context:
+ outer_root_context[_SLOT_COMPONENT_ASSOC_KEY] = context[_SLOT_COMPONENT_ASSOC_KEY]
+ if _FILLED_SLOTS_CONTENT_CONTEXT_KEY in context:
+ outer_root_context[_FILLED_SLOTS_CONTENT_CONTEXT_KEY] = context[_FILLED_SLOTS_CONTENT_CONTEXT_KEY]
+
+ context[_OUTER_ROOT_CTX_CONTEXT_KEY] = outer_root_context
-def capture_root_context(context: Context) -> None:
- """
- Set the root context if it was not set before.
-
- Root context is the top-most context, AKA the context that was passed to
- the initial `Template.render()`.
- We pass through the root context to allow configure how slot fills should be rendered.
-
- See the `SLOT_CONTEXT_BEHAVIOR` setting.
- """
- root_ctx_already_defined = _OUTER_CONTEXT_CONTEXT_KEY in context
- if not root_ctx_already_defined:
- set_root_context(context, copy(context))
-
-
-def set_slot_component_association(context: Context, slot_id: str, component_id: str) -> None:
+def set_slot_component_association(
+ context: Context,
+ slot_id: str,
+ component_id: str,
+) -> None:
"""
Set association between a Slot and a Component in the current context.
- We use SlotNodes to render slot fills. SlotNodes are created only at Template parse time.
- However, when we are using components with slots in (another) template, we can render
- the same component multiple time. So we can have multiple FillNodes intended to be used
- with the same SlotNode.
+ We use SlotNodes to render slot fills. SlotNodes are created only at Template
+ parse time.
+ However, when we refer to components with slots in (another) template (using
+ `{% component %}`), we can render the same component multiple time. So we can
+ have multiple FillNodes intended to be used with the same SlotNode.
- So how do we tell the SlotNode which FillNode to render? We do so by tagging the ComponentNode
- and FillNodes with a unique component_id, which ties them together. And then we tell SlotNode
- which component_id to use to be able to find the correct Component/Fill.
+ So how do we tell the SlotNode which FillNode to render? We do so by tagging
+ the ComponentNode and FillNodes with a unique component_id, which ties them
+ together. And then we tell SlotNode which component_id to use to be able to
+ find the correct Component/Fill.
- We don't want to store this info on the Nodes themselves, as we need to treat them as
- immutable due to caching of Templates by Django.
+ We don't want to store this info on the Nodes themselves, as we need to treat
+ them as immutable due to caching of Templates by Django.
- Hence, we use the Context to store the associations of SlotNode <-> Component for
- the current context stack.
+ Hence, we use the Context to store the associations of SlotNode <-> Component
+ for the current context stack.
"""
- key = (_SLOT_COMPONENT_ASSOC_KEY, slot_id)
- context[key] = component_id
+ context[_SLOT_COMPONENT_ASSOC_KEY][slot_id] = component_id
def get_slot_component_association(context: Context, slot_id: str) -> str:
@@ -118,5 +166,17 @@ def get_slot_component_association(context: Context, slot_id: str) -> str:
See `set_slot_component_association` for more details.
"""
- key = (_SLOT_COMPONENT_ASSOC_KEY, slot_id)
- return context[key]
+ return context[_SLOT_COMPONENT_ASSOC_KEY][slot_id]
+
+
+def copy_forloop_context(from_context: Context, to_context: Context) -> None:
+ """Forward the info about the current loop"""
+ # Note that the ForNode (which implements for loop behavior) does not
+ # only add the `forloop` key, but also keys corresponding to the loop elements
+ # So if the loop syntax is `{% for my_val in my_lists %}`, then ForNode also
+ # sets a `my_val` key.
+ # For this reason, instead of copying individual keys, we copy the whole stack layer
+ # set by ForNode.
+ if "forloop" in from_context:
+ forloop_dict_index = find_last_index(from_context.dicts, lambda d: "forloop" in d)
+ to_context.update(from_context.dicts[forloop_dict_index])
diff --git a/src/django_components/slots.py b/src/django_components/slots.py
index cdaa21d0..98d6f795 100644
--- a/src/django_components/slots.py
+++ b/src/django_components/slots.py
@@ -10,7 +10,13 @@ from django.template.exceptions import TemplateSyntaxError
from django.utils.safestring import SafeString, mark_safe
from django_components.app_settings import SlotContextBehavior, app_settings
-from django_components.context import get_root_context, get_slot_component_association, get_slot_fill, set_slot_fill
+from django_components.context import (
+ copy_forloop_context,
+ get_outer_root_context,
+ get_slot_component_association,
+ get_slot_fill,
+ set_slot_fill,
+)
from django_components.logger import trace_msg
from django_components.node import nodelist_has_content
from django_components.utils import gen_id
@@ -139,14 +145,16 @@ class SlotNode(Node):
See SlotContextBehavior for the description of each option.
"""
- root_ctx = get_root_context(context) or Context()
+ root_ctx = get_outer_root_context(context) or Context()
if app_settings.SLOT_CONTEXT_BEHAVIOR == SlotContextBehavior.ALLOW_OVERRIDE:
return context
elif app_settings.SLOT_CONTEXT_BEHAVIOR == SlotContextBehavior.ISOLATED:
- return root_ctx
+ new_context: Context = copy(root_ctx)
+ copy_forloop_context(context, new_context)
+ return new_context
elif app_settings.SLOT_CONTEXT_BEHAVIOR == SlotContextBehavior.PREFER_ROOT:
- new_context: Context = copy(context)
+ new_context = copy(context)
new_context.update(root_ctx.flatten())
return new_context
else:
@@ -483,8 +491,8 @@ def _report_slot_errors(
for fill_name in unmatched_fills:
fuzzy_slot_name_matches = difflib.get_close_matches(fill_name, unfilled_slots, n=1, cutoff=0.7)
msg = (
- f"Component '{registered_name}' passed fill "
- f"that refers to undefined slot: '{fill_name}'."
+ f"Component '{registered_name}' passed fill that refers to undefined slot:"
+ f" '{fill_name}'."
f"\nUnfilled slot names are: {sorted(unfilled_slots)}."
)
if fuzzy_slot_name_matches:
diff --git a/src/django_components/utils.py b/src/django_components/utils.py
index 774c6892..a0525869 100644
--- a/src/django_components/utils.py
+++ b/src/django_components/utils.py
@@ -1,6 +1,6 @@
import glob
from pathlib import Path
-from typing import List, NamedTuple, Optional
+from typing import Any, Callable, List, NamedTuple, Optional
from django.template.engine import Engine
@@ -49,3 +49,10 @@ def gen_id(length: int = 5) -> str:
# Pad the ID with `0`s up to 4 digits, e.g. `0007`
return f"{_id:04}"
+
+
+def find_last_index(lst: List, predicate: Callable[[Any], bool]) -> Any:
+ for r_idx, elem in enumerate(reversed(lst)):
+ if predicate(elem):
+ return len(lst) - 1 - r_idx
+ return -1
diff --git a/tests/test_templatetags.py b/tests/test_templatetags.py
index 937a91b2..ab8ea7d8 100644
--- a/tests/test_templatetags.py
+++ b/tests/test_templatetags.py
@@ -1,8 +1,9 @@
import re
import textwrap
-from typing import Callable, Optional
+from typing import Any, Callable, Dict, Optional
from django.template import Context, Template, TemplateSyntaxError
+from django.test import override_settings
# isort: off
from .django_test_setup import * # NOQA
@@ -85,6 +86,34 @@ class ComponentWithDefaultAndRequiredSlot(component.Component):
template_name = "template_with_default_and_required_slot.html"
+class _ComplexChildComponent(component.Component):
+ template = """
+ {% load component_tags %}
+
+ {% slot "content" default %}
+ No slot!
+ {% endslot %}
+
+ """
+
+
+class _ComplexParentComponent(component.Component):
+ template = """
+ {% load component_tags %}
+ ITEMS: {{ items }}
+ {% for item in items %}
+
+ {% component "complex_child" %}
+ {{ item.value }}
+ {% endcomponent %}
+
+ {% endfor %}
+ """
+
+ def get_context_data(self, items, *args, **kwargs) -> Dict[str, Any]:
+ return {"items": items}
+
+
class ComponentTemplateTagTest(BaseTestCase):
def setUp(self):
# NOTE: component.registry is global, so need to clear before each test
@@ -1019,6 +1048,8 @@ class ComponentNestingTests(BaseTestCase):
super().setUpClass()
component.registry.register("dashboard", _DashboardComponent)
component.registry.register("calendar", _CalendarComponent)
+ component.registry.register("complex_child", _ComplexChildComponent)
+ component.registry.register("complex_parent", _ComplexParentComponent)
@classmethod
def tearDownClass(cls) -> None:
@@ -1052,6 +1083,100 @@ class ComponentNestingTests(BaseTestCase):
"""
self.assertHTMLEqual(rendered, expected)
+ @override_settings(
+ COMPONENTS={
+ "context_behavior": "isolated",
+ "slot_context_behavior": "isolated",
+ }
+ )
+ def test_component_nesting_slot_inside_component_fill_isolated(self):
+ template = Template(
+ """
+ {% load component_tags %}
+ {% component "dashboard" %}{% endcomponent %}
+ """
+ )
+ rendered = template.render(Context({"items": [1, 2, 3]}))
+ expected = """
+
+
+
+ Welcome to your dashboard!
+
+
+ Here are your to-do items for today:
+
+
+
+
+
+
+
+ Whoa!
+
+
+ Here are your to-do items for today:
+
+
+
+
+
1
+
+
+ 2
+
+
+ 3
+
+ """
+ self.assertHTMLEqual(rendered, expected)
+
def test_component_nesting_component_with_fill_and_super(self):
template = Template(
"""
diff --git a/tests/testutils.py b/tests/testutils.py
index f45b335f..494accc8 100644
--- a/tests/testutils.py
+++ b/tests/testutils.py
@@ -1,6 +1,7 @@
+from typing import List
from unittest.mock import Mock
-from django.template import Context
+from django.template import Context, Node
from django.template.response import TemplateResponse
from django.test import SimpleTestCase
@@ -32,3 +33,22 @@ def create_and_process_template_response(template, context=None, use_middleware=
else:
response.render()
return response.content.decode("utf-8")
+
+
+def print_nodes(nodes: List[Node], indent=0) -> None:
+ """
+ Render a Nodelist, inlining child nodes with extra on separate lines and with
+ extra indentation.
+ """
+ for node in nodes:
+ child_nodes: List[Node] = []
+ for attr in node.child_nodelists:
+ attr_child_nodes = getattr(node, attr, None) or []
+ if attr_child_nodes:
+ child_nodes.extend(attr_child_nodes)
+
+ repr = str(node)
+ repr = "\n".join([(" " * 4 * indent) + line for line in repr.split("\n")])
+ print(repr)
+ if child_nodes:
+ print_nodes(child_nodes, indent=indent + 1)