90 lines
2.2 KiB
Python
90 lines
2.2 KiB
Python
"""
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schedule_v5.py: cached properties using functools
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>>> event = Record.fetch('event.33950')
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>>> event
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<Event 'There *Will* Be Bugs'>
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>>> event.venue
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<Record serial=1449>
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>>> event.venue_serial
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1449
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>>> event.venue.name
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'Portland 251'
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# tag::SCHEDULE3_DEMO[]
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>>> for spkr in event.speakers: # <3>
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... print(f'{spkr.serial}: {spkr.name}')
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...
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3471: Anna Martelli Ravenscroft
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5199: Alex Martelli
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# end::SCHEDULE3_DEMO[]
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"""
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import json
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import inspect
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from functools import cached_property, cache
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JSON_PATH = 'data/osconfeed.json'
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class Record:
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__index = None
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def __init__(self, **kwargs):
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self.__dict__.update(kwargs)
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def __repr__(self):
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cls_name = self.__class__.__name__
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return f'<{cls_name} serial={self.serial!r}>'
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@staticmethod
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def fetch(key):
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if Record.__index is None:
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Record.__index = load()
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return Record.__index[key]
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class Event(Record):
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def __repr__(self):
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if hasattr(self, 'name'):
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cls_name = self.__class__.__name__
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return f'<{cls_name} {self.name!r}>'
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else:
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return super().__repr__()
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# tag::SCHEDULE5_CACHED_PROPERTY[]
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@cached_property
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def venue(self):
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key = f'venue.{self.venue_serial}'
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return self.__class__.fetch(key)
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# end::SCHEDULE5_CACHED_PROPERTY[]
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# tag::SCHEDULE5_PROPERTY_OVER_CACHE[]
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@property # <1>
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@cache # <2>
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def speakers(self):
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spkr_serials = self.__dict__['speakers']
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fetch = self.__class__.fetch
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return [fetch(f'speaker.{key}')
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for key in spkr_serials]
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# end::SCHEDULE5_PROPERTY_OVER_CACHE[]
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def load(path=JSON_PATH):
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records = {}
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with open(path) as fp:
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raw_data = json.load(fp)
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for collection, raw_records in raw_data['Schedule'].items():
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record_type = collection[:-1]
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cls_name = record_type.capitalize()
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cls = globals().get(cls_name, Record)
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if inspect.isclass(cls) and issubclass(cls, Record):
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factory = cls
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else:
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factory = Record
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for raw_record in raw_records:
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key = f'{record_type}.{raw_record["serial"]}'
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records[key] = factory(**raw_record)
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return records
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