django-components/src/django_components/component.py

370 lines
15 KiB
Python

import inspect
import os
import sys
from pathlib import Path
from typing import Any, ClassVar, Dict, List, Mapping, MutableMapping, Optional, Sequence, Tuple, Type, Union
from django.core.exceptions import ImproperlyConfigured
from django.forms.widgets import Media, MediaDefiningClass
from django.http import HttpResponse
from django.template.base import FilterExpression, Node, NodeList, Template, TextNode
from django.template.context import Context
from django.template.loader import get_template
from django.utils.html import escape
from django.utils.safestring import SafeString, mark_safe
from django.views import View
# Global registry var and register() function moved to separate module.
# Defining them here made little sense, since 1) component_tags.py and component.py
# rely on them equally, and 2) it made it difficult to avoid circularity in the
# 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.logger import logger
from django_components.middleware import is_dependency_middleware_active
from django_components.slots import (
FillNode,
FillContent,
SlotName,
render_component_template_with_slots,
)
from django_components.utils import search
RENDERED_COMMENT_TEMPLATE = "<!-- _RENDERED {name} -->"
class SimplifiedInterfaceMediaDefiningClass(MediaDefiningClass):
def __new__(mcs, name: str, bases: Tuple[Type, ...], attrs: Dict[str, Any]) -> Type:
# NOTE: Skip template/media file resolution when then Component class ITSELF
# is being created.
if "__module__" in attrs and attrs["__module__"] == "django_components.component":
return super().__new__(mcs, name, bases, attrs)
if "Media" in attrs:
media: Component.Media = attrs["Media"]
# Allow: class Media: css = "style.css"
if hasattr(media, "css") and isinstance(media.css, str):
media.css = [media.css]
# Allow: class Media: css = ["style.css"]
if hasattr(media, "css") and isinstance(media.css, list):
media.css = {"all": media.css}
# Allow: class Media: css = {"all": "style.css"}
if hasattr(media, "css") and isinstance(media.css, dict):
for media_type, path_list in media.css.items():
if isinstance(path_list, str):
media.css[media_type] = [path_list] # type: ignore
# Allow: class Media: js = "script.js"
if hasattr(media, "js") and isinstance(media.js, str):
media.js = [media.js]
_resolve_component_relative_files(attrs)
return super().__new__(mcs, name, bases, attrs)
def _resolve_component_relative_files(attrs: MutableMapping) -> None:
"""
Check if component's HTML, JS and CSS files refer to files in the same directory
as the component class. If so, modify the attributes so the class Django's rendering
will pick up these files correctly.
"""
component_name = attrs["__qualname__"]
# Derive the full path of the file where the component was defined
module_name = attrs["__module__"]
module_obj = sys.modules[module_name]
file_path = module_obj.__file__
if not file_path:
logger.debug(
f"Could not resolve the path to the file for component '{component_name}'."
" Paths for HTML, JS or CSS templates will NOT be resolved relative to the component file."
)
return
# Prepare all possible directories we need to check when searching for
# component's template and media files
components_dirs = search().searched_dirs
# Get the directory where the component class is defined
try:
comp_dir_abs, comp_dir_rel = _get_dir_path_from_component_path(file_path, components_dirs)
except RuntimeError:
# If no dir was found, we assume that the path is NOT relative to the component dir
logger.debug(
f"No component directory found for component '{component_name}' in {file_path}"
" If this component defines HTML, JS or CSS templates relatively to the component file,"
" then check that the component's directory is accessible from one of the paths"
" specified in the Django's 'STATICFILES_DIRS' settings."
)
return
# Check if filepath refers to a file that's in the same directory as the component class.
# If yes, modify the path to refer to the relative file.
# If not, don't modify anything.
def resolve_file(filepath: str) -> str:
maybe_resolved_filepath = os.path.join(comp_dir_abs, filepath)
component_import_filepath = os.path.join(comp_dir_rel, filepath)
if os.path.isfile(maybe_resolved_filepath):
logger.debug(
f"Interpreting template '{filepath}' of component '{module_name}' relatively to component file"
)
return component_import_filepath
logger.debug(
f"Interpreting template '{filepath}' of component '{module_name}' relatively to components directory"
)
return filepath
# Check if template name is a local file or not
if "template_name" in attrs and attrs["template_name"]:
attrs["template_name"] = resolve_file(attrs["template_name"])
if "Media" in attrs:
media = attrs["Media"]
# Now check the same for CSS files
if hasattr(media, "css") and isinstance(media.css, dict):
for media_type, path_list in media.css.items():
media.css[media_type] = [resolve_file(filepath) for filepath in path_list]
# And JS
if hasattr(media, "js") and isinstance(media.js, list):
media.js = [resolve_file(filepath) for filepath in media.js]
def _get_dir_path_from_component_path(
abs_component_file_path: str,
candidate_dirs: Union[List[str], List[Path]],
) -> Tuple[str, str]:
comp_dir_path_abs = os.path.dirname(abs_component_file_path)
# From all dirs defined in settings.STATICFILES_DIRS, find one that's the parent
# to the component file.
root_dir_abs = None
for candidate_dir in candidate_dirs:
candidate_dir_abs = os.path.abspath(candidate_dir)
if comp_dir_path_abs.startswith(candidate_dir_abs):
root_dir_abs = candidate_dir_abs
break
if root_dir_abs is None:
raise RuntimeError(
f"Failed to resolve template directory for component file '{abs_component_file_path}'",
)
# Derive the path from matched STATICFILES_DIRS to the dir where the current component file is.
comp_dir_path_rel = os.path.relpath(comp_dir_path_abs, candidate_dir_abs)
# Return both absolute and relative paths:
# - Absolute path is used to check if the file exists
# - Relative path is used for defining the import on the component class
return comp_dir_path_abs, comp_dir_path_rel
class Component(View, metaclass=SimplifiedInterfaceMediaDefiningClass):
# Either template_name or template must be set on subclass OR subclass must implement get_template() with
# non-null return.
class_hash: ClassVar[int]
template_name: ClassVar[Optional[str]] = None
template: Optional[str] = None
js: Optional[str] = None
css: Optional[str] = None
media: Media
class Media:
css: Optional[Union[str, List[str], Dict[str, str], Dict[str, List[str]]]] = None
js: Optional[Union[str, List[str]]] = None
def __init__(
self,
registered_name: Optional[str] = None,
outer_context: Optional[Context] = None,
fill_content: dict[str, FillContent] = {}, # type: ignore
):
self.registered_name: Optional[str] = registered_name
self.outer_context: Context = outer_context or Context()
self.fill_content = fill_content
def __init_subclass__(cls, **kwargs: Any) -> None:
cls.class_hash = hash(inspect.getfile(cls) + cls.__name__)
def get_context_data(self, *args: Any, **kwargs: Any) -> Dict[str, Any]:
return {}
def get_template_name(self, context: Mapping) -> Optional[str]:
return self.template_name
def get_template_string(self, context: Mapping) -> Optional[str]:
return self.template
def render_dependencies(self) -> SafeString:
"""Helper function to render all dependencies for a component."""
dependencies = []
css_deps = self.render_css_dependencies()
if css_deps:
dependencies.append(css_deps)
js_deps = self.render_js_dependencies()
if js_deps:
dependencies.append(js_deps)
return mark_safe("\n".join(dependencies))
def render_css_dependencies(self) -> SafeString:
"""Render only CSS dependencies available in the media class or provided as a string."""
if self.css is not None:
return mark_safe(f"<style>{self.css}</style>")
return mark_safe("\n".join(self.media.render_css()))
def render_js_dependencies(self) -> SafeString:
"""Render only JS dependencies available in the media class or provided as a string."""
if self.js is not None:
return mark_safe(f"<script>{self.js}</script>")
return mark_safe("\n".join(self.media.render_js()))
def get_template(self, context: Mapping) -> Template:
template_string = self.get_template_string(context)
if template_string is not None:
return Template(template_string)
template_name = self.get_template_name(context)
if template_name is not None:
return get_template(template_name).template
raise ImproperlyConfigured(
f"Either 'template_name' or 'template' must be set for Component {type(self).__name__}."
f"Note: this attribute is not required if you are overriding the class's `get_template*()` methods."
)
def render(
self,
context_data: Dict[str, Any],
slots_data: Optional[Dict[SlotName, str]] = None,
escape_slots_content: bool = True,
) -> str:
# 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)
template = self.get_template(context)
if slots_data:
self._fill_slots(slots_data, escape_slots_content)
return render_component_template_with_slots(template, context, self.fill_content, self.registered_name)
def render_to_response(
self,
context_data: Dict[str, Any],
slots_data: Optional[Dict[SlotName, str]] = None,
escape_slots_content: bool = True,
*args: Any,
**kwargs: Any,
) -> HttpResponse:
return HttpResponse(
self.render(context_data, slots_data, escape_slots_content),
*args,
**kwargs,
)
def _fill_slots(
self,
slots_data: Dict[SlotName, str],
escape_content: bool = True,
) -> None:
"""Fill component slots outside of template rendering."""
self.fill_content = {
slot_name: FillContent(
TextNode(escape(content) if escape_content else content),
None,
)
for (slot_name, content) in slots_data.items()
}
class ComponentNode(Node):
"""Django.template.Node subclass that renders a django-components component"""
def __init__(
self,
name_fexp: FilterExpression,
context_args: List[FilterExpression],
context_kwargs: Mapping[str, FilterExpression],
isolated_context: bool = False,
fill_nodes: Sequence[FillNode] = (),
) -> None:
self.name_fexp = name_fexp
self.context_args = context_args or []
self.context_kwargs = context_kwargs or {}
self.isolated_context = isolated_context
self.fill_nodes = fill_nodes
self.nodelist = NodeList(fill_nodes)
def __repr__(self) -> str:
return "<ComponentNode: {}. Contents: {!r}>".format(
self.name_fexp,
getattr(self, "nodelist", None), # 'nodelist' attribute only assigned later.
)
def render(self, context: Context) -> str:
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.
root_ctx_already_defined = OUTER_CONTEXT_CONTEXT_KEY in context
if not root_ctx_already_defined:
context.push({OUTER_CONTEXT_CONTEXT_KEY: context.__copy__()})
# 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
resolved_context_args = [safe_resolve(arg, context) for arg in self.context_args]
resolved_context_kwargs = {key: safe_resolve(kwarg, context) for key, kwarg in self.context_kwargs.items()}
if len(self.fill_nodes) == 1 and self.fill_nodes[0].is_implicit:
fill_content: Dict[str, FillContent] = {DEFAULT_SLOT_KEY: FillContent(self.fill_nodes[0].nodelist, None)}
else:
fill_content = {}
for fill_node in self.fill_nodes:
# Note that outer component context is used to resolve variables in
# fill tag.
resolved_name = fill_node.name_fexp.resolve(context)
resolved_fill_alias = fill_node.resolve_alias(context, resolved_component_name)
fill_content[resolved_name] = FillContent(fill_node.nodelist, resolved_fill_alias)
component: Component = component_cls(
registered_name=resolved_component_name,
outer_context=context,
fill_content=fill_content,
)
component_context: dict = component.get_context_data(*resolved_context_args, **resolved_context_kwargs)
# 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.
orig_ctx = context
context = context.new()
context.push({OUTER_CONTEXT_CONTEXT_KEY: orig_ctx})
with context.update(component_context):
rendered_component = component.render(context)
if is_dependency_middleware_active():
return RENDERED_COMMENT_TEMPLATE.format(name=resolved_component_name) + rendered_component
else:
return rendered_component
def safe_resolve(context_item: FilterExpression, context: Context) -> Any:
"""Resolve FilterExpressions and Variables in context if possible. Return other items unchanged."""
return context_item.resolve(context) if hasattr(context_item, "resolve") else context_item