104 lines
3.3 KiB
Python
104 lines
3.3 KiB
Python
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 attribute
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has to be set. The metaclass (SignalConnectMetaClass) does the rest of the
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magic.
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"""
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signal = Signal()
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name = 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 check_and_update_data(self, projector_object, config_entry):
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"""
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Checks projector element data via self.check_data() and updates
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them via self.update_data(). The projector object and the config
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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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self.check_data()
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return self.update_data() or {}
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def check_data(self):
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"""
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Method can be overridden to validate projector element data. This
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may raise ProjectorException in case of an error.
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Default: Does nothing.
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"""
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pass
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def update_data(self):
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"""
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Method can be overridden to update the projector element data
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output. This should return a dictonary. Use this for server
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calculated data which have to be forwared to the client.
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Default: Does nothing.
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"""
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pass
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def get_requirements(self, config_entry):
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"""
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Returns an iterable of ProjectorRequirement instances to setup
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which views should be accessable for projector clients if the
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projector element is active. The config_entry has to be given.
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"""
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return ()
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class ProjectorRequirement:
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"""
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Container for required views. Such a view is defined by its class, its
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action and its kwargs which come from the URL path.
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"""
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def __init__(self, view_class, view_action, **kwargs):
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self.view_class = view_class
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self.view_action = view_action
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self.kwargs = kwargs
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def is_currently_required(self, view_instance):
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"""
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Returns True if the view_instance matches the initiated data of this
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requirement.
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"""
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if not type(view_instance) == self.view_class:
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result = False
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elif not view_instance.action == self.view_action:
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result = False
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else:
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result = True
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for key in view_instance.kwargs:
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if not self.kwargs[key] == view_instance.kwargs[key]:
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result = False
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break
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return result
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