67 lines
2.1 KiB
Python
67 lines
2.1 KiB
Python
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from django.dispatch import Signal
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from .dispatch import SignalConnectMetaClass
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class ProjectorElement(object, metaclass=SignalConnectMetaClass):
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"""
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Base class for an element on the projector.
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Every app which wants to add projector elements has to create classes
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subclassing from this base class with different names. The name and
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scripts attributes have to be set. The metaclass
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(SignalConnectMetaClass) does the rest of the magic.
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"""
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signal = Signal()
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name = None
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scripts = None
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def __init__(self, **kwargs):
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"""
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Initializes the projector element instance. This is done when the
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signal is sent.
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Because of Django's signal API, we have to take wildcard keyword
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arguments. But they are not used here.
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"""
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pass
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@classmethod
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def get_dispatch_uid(cls):
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"""
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Returns the classname as a unique string for each class. Returns None
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for the base class so it will not be connected to the signal.
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"""
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if not cls.__name__ == 'ProjectorElement':
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return cls.__name__
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def get_data(self, projector_object, config_entry):
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"""
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Returns all data to be sent to the client. The projector object and
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the config entry have to be given.
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"""
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self.projector_object = projector_object
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self.config_entry = config_entry
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assert self.config_entry.get('name') == self.name, (
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'To get data of a projector element, the correct config entry has to be given.')
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return {
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'scripts': self.get_scripts(),
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'context': self.get_context()}
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def get_scripts(self):
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"""
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Returns ...?
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"""
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# TODO: Write docstring
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if self.scripts is None:
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raise NotImplementedError(
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'A projector element class must define either a '
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'get_scripts method or have a scripts argument.')
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return self.scripts
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def get_context(self):
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"""
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Returns the context of the projector element.
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"""
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return None
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