Django snippets: Clean-ish memcached key generation

Clean-ish memcached key generation

from django.utils.hashcompat import md5_constructor

drop_chars = ''.join(['%c' % c for c in range(32)]) + ' '

def cache_key_clean(value):
    """
    Make a key of the first up to 228 valid characters of the value,
    appended with the md5 of the whole value.
    """
    md5_hash = md5_constructor(value).hexdigest()
    return ''.join([value.translate(None,drop_chars)[:228], md5_hash])

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Based on snippet #1212 along with it's comments.

Replaced the for loop with translate.

example usage:

from django.core.cache import cache
from mysnippet import cache_key_clean

expensive_func = lambda x: 'x{0}x'.format(x)

input_string = "I wanted a nice value."
key = cache_key_clean(input_string)
result = cache.get(key)
if result is None:
    result = expensive_func(input_string)
    cache.set(key, result)

Author:: iiie
Posted:: September 17, 2012
Language:: Python
Django Version:: 1.4
Tags:: memcache cache
Score:: 0 (after 0 ratings)

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