mirror of
https://github.com/django-components/django-components.git
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116 lines
3.8 KiB
Python
116 lines
3.8 KiB
Python
import warnings
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from copy import copy
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from functools import lru_cache
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from itertools import chain
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from django.conf import settings
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from django.forms.widgets import MediaDefiningClass
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from django.template.base import NodeList, TokenType
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from django.template.loader import get_template
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from django.utils.safestring import mark_safe
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# Allow "component.AlreadyRegistered" instead of having to import these everywhere
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from django_components.component_registry import AlreadyRegistered, ComponentRegistry, NotRegistered # noqa
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TEMPLATE_CACHE_SIZE = getattr(settings, "COMPONENTS", {}).get('TEMPLATE_CACHE_SIZE', 128)
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class Component(metaclass=MediaDefiningClass):
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def __init__(self, component_name):
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self.__component_name = component_name
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self.instance_template = None
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self.slots = {}
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def context(self):
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return {}
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def template(self, context):
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raise NotImplementedError("Missing template() method on component")
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def render_dependencies(self):
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"""Helper function to access media.render()"""
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return self.media.render()
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def render_css_dependencies(self):
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"""Render only CSS dependencies available in the media class."""
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return mark_safe("\n".join(self.media.render_css()))
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def render_js_dependencies(self):
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"""Render only JS dependencies available in the media class."""
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return mark_safe("\n".join(self.media.render_js()))
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@staticmethod
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def slots_in_template(template):
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return {node.name: node.nodelist for node in template.template.nodelist if is_slot_node(node)}
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@lru_cache(maxsize=TEMPLATE_CACHE_SIZE)
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def compile_instance_template(self, template_name):
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"""Use component's base template and the slots used for this instance to compile
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a unified template for this instance."""
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component_template = get_template(template_name)
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slots_in_template = self.slots_in_template(component_template)
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defined_slot_names = set(slots_in_template.keys())
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filled_slot_names = set(self.slots.keys())
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unexpected_slots = filled_slot_names - defined_slot_names
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if unexpected_slots:
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if settings.DEBUG:
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warnings.warn(
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"Component {} was provided with unexpected slots: {}".format(
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self.__component_name, unexpected_slots
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)
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)
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for unexpected_slot in unexpected_slots:
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del self.slots[unexpected_slot]
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combined_slots = dict(slots_in_template, **self.slots)
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if combined_slots:
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# Replace slot nodes with their nodelists, then combine into a single, flat nodelist
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node_iterator = ([node] if not is_slot_node(node) else combined_slots[node.name]
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for node in component_template.template.nodelist)
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instance_template = copy(component_template.template)
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instance_template.nodelist = NodeList(chain.from_iterable(node_iterator))
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else:
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instance_template = component_template.template
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return instance_template
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def render(self, context):
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template_name = self.template(context)
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instance_template = self.compile_instance_template(template_name)
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return instance_template.render(context)
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class Media:
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css = {}
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js = []
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def is_slot_node(node):
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return node.token.token_type == TokenType.BLOCK and node.token.split_contents()[0] == "slot"
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# This variable represents the global component registry
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registry = ComponentRegistry()
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def register(name):
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"""Class decorator to register a component.
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Usage:
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@register("my_component")
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class MyComponent(component.Component):
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...
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"""
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def decorator(component):
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registry.register(name=name, component=component)
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return component
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return decorator
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