89 lines
2.3 KiB
Python
89 lines
2.3 KiB
Python
"""A simple key/value store backed by a json file
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Keys need to be convertable to str
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Values can be anything json can store, including a dict
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Usage:
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import database
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with database.Database() as db:
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print(db.get("hello", "default"))
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db.set("foo", "world")
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db.delete("bar")
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Or, to make things even easier, there are three static function:
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import database
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print(database.get("hello", "default"))
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database.set("foo", "world")
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database.delete("bar")
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"""
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___license___ = "MIT"
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import os, json
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class Database:
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def __init__(self, filename = "config.json"):
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self.filename = filename
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self.dirty = False
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try:
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with open(filename, "rt") as file:
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self.data = json.loads(file.read())
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except (OSError, ValueError):
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print("Database %s doesn't exists or is invalid, creating new" % (filename))
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self.data = {}
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self.dirty = True
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self.flush()
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def set(self, key, value):
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"""Sets a value for a given key.
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'key' gets converted into a string
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'value' can be anything that json can store, including a dict
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"""
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self.data[key] = value
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self.dirty = True
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def get(self, key, default_value = None):
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"""Returns the value for a given key.
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If key is not found 'default_value' will be returned
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"""
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return self.data[key] if key in self.data else default_value
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def delete(self, key):
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"""Deletes a key/value pair"""
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if key in self.data:
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del self.data[key]
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self.dirty = True
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def flush(self):
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"""Writes changes to flash"""
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if self.dirty:
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with open(self.filename, "wt") as file:
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file.write(json.dumps(self.data))
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file.flush()
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os.sync()
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self.dirty = False
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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self.flush()
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def get(key, default_value = None, *args, **kwargs):
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with Database(*args, **kwargs) as db:
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return db.get(key, default_value)
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def set(key, value, *args, **kwargs):
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with Database(*args, **kwargs) as db:
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return db.set(key, value)
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def delete(key, *args, **kwargs):
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with Database(*args, **kwargs) as db:
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return db.delete(key)
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