mirror of
https://github.com/Hopiu/django-imagekit.git
synced 2026-03-16 21:30:23 +00:00
149 lines
4.6 KiB
Python
149 lines
4.6 KiB
Python
from .exceptions import AlreadyRegistered, NotRegistered
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from .signals import (before_access, source_created, source_changed,
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source_deleted)
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class GeneratorRegistry(object):
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"""
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An object for registering generators (specs). This registry provides
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a convenient way for a distributable app to define default generators
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without locking the users of the app into it.
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"""
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def __init__(self):
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self._generators = {}
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def register(self, id, generator):
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if id in self._generators:
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raise AlreadyRegistered('The spec or generator with id %s is'
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' already registered' % id)
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self._generators[id] = generator
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def unregister(self, id, generator):
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# TODO: Either don't require the generator, or--if we do--assert that it's registered with the provided id
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try:
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del self._generators[id]
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except KeyError:
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raise NotRegistered('The spec or generator with id %s is not'
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' registered' % id)
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def get(self, id, **kwargs):
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try:
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generator = self._generators[id]
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except KeyError:
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raise NotRegistered('The spec or generator with id %s is not'
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' registered' % id)
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if callable(generator):
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return generator(**kwargs)
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else:
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return generator
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def get_ids(self):
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return self._generators.keys()
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class SourceGroupRegistry(object):
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"""
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An object for registering source groups with specs. The two are
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associated with each other via a string id. We do this (as opposed to
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associating them directly by, for example, putting a ``source_groups``
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attribute on specs) so that specs can be overridden without losing the
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associated sources. That way, a distributable app can define its own
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specs without locking the users of the app into it.
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"""
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_signals = [
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source_created,
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source_changed,
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source_deleted,
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]
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def __init__(self):
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self._source_groups = {}
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for signal in self._signals:
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signal.connect(self.source_group_receiver)
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before_access.connect(self.before_access_receiver)
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def register(self, spec_id, source_groups):
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"""
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Associates source groups with a spec id
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"""
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for source_group in source_groups:
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if source_group not in self._source_groups:
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self._source_groups[source_group] = set()
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self._source_groups[source_group].add(spec_id)
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def unregister(self, spec_id, source_groups):
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"""
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Disassociates sources with a spec id
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"""
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for source_group in source_groups:
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try:
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self._source_groups[source_group].remove(spec_id)
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except KeyError:
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continue
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def get(self, spec_id):
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return [source_group for source_group in self._source_groups
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if spec_id in self._source_groups[source_group]]
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def before_access_receiver(self, sender, generator, file, **kwargs):
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generator.image_cache_strategy.invoke_callback('before_access', file)
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def source_group_receiver(self, sender, source, signal, info, **kwargs):
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"""
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Redirects signals dispatched on sources to the appropriate specs.
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"""
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source_group = sender
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if source_group not in self._source_groups:
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return
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for spec in (generator_registry.get(id, source=source, **info)
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for id in self._sources_groups[source_group]):
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event_name = {
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source_created: 'source_created',
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source_changed: 'source_changed',
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source_deleted: 'source_deleted',
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}
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spec._handle_source_event(event_name, source)
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class Register(object):
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"""
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Register specs and sources.
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"""
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def spec(self, id, spec=None):
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if spec is None:
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# Return a decorator
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def decorator(cls):
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self.spec(id, cls)
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return cls
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return decorator
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generator_registry.register(id, spec)
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def sources(self, spec_id, sources):
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source_group_registry.register(spec_id, sources)
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class Unregister(object):
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"""
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Unregister specs and sources.
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"""
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def spec(self, id, spec):
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generator_registry.unregister(id, spec)
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def sources(self, spec_id, sources):
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source_group_registry.unregister(spec_id, sources)
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generator_registry = GeneratorRegistry()
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source_group_registry = SourceGroupRegistry()
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register = Register()
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unregister = Unregister()
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