79 lines
No EOL
2.5 KiB
Python
79 lines
No EOL
2.5 KiB
Python
# Copyright (c) 2012 Web Notes Technologies Pvt Ltd (http://erpnext.com)
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#
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# MIT License (MIT)
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#
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# Permission is hereby granted, free of charge, to any person obtaining a
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# copy of this software and associated documentation files (the "Software"),
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# to deal in the Software without restriction, including without limitation
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# the rights to use, copy, modify, merge, publish, distribute, sublicense,
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# and/or sell copies of the Software, and to permit persons to whom the
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# Software is furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
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# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
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# OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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#
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"""
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Simple Caching:
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Stores key-value pairs in database and enables simple caching
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get_item(key).get() returns the cached value if not expired (else returns null)
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get_item(key).set(interval = 60000) sets a value to cache, expiring after x seconds
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get_item(key).clear() clears an old value
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setup() sets up cache
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"""
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import webnotes
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class CacheItem:
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def __init__(self, key):
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"""create a new cache"""
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self.key = key
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def get(self):
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"""get value"""
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try:
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return webnotes.conn.sql("select `value` from __CacheItem where `key`=%s and expires_on > NOW()", self.key)[0][0]
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except Exception:
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return None
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def set(self, value, interval=6000):
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"""set a new value, with interval"""
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try:
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self.clear()
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webnotes.conn.sql("""INSERT INTO
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__CacheItem (`key`, `value`, expires_on)
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VALUES
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(%s, %s, addtime(now(), sec_to_time(%s)))
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""", (self.key, str(value), interval))
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except Exception, e:
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if e.args[0]==1146:
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setup()
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self.set(value, interval)
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else: raise e
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def clear(self):
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"""clear the item"""
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webnotes.conn.sql("delete from __CacheItem where `key`=%s", self.key)
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def setup():
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webnotes.conn.commit()
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webnotes.conn.sql("""create table __CacheItem(
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`key` VARCHAR(180) NOT NULL PRIMARY KEY,
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`value` TEXT,
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`expires_on` TIMESTAMP
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)""")
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webnotes.conn.begin()
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def get_item(key):
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"""returns get CacheItem object"""
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return CacheItem(key)
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pass |