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"""
Tiny
A reversible base62 ID obfuscater
Authors:
Jacob DeHart (original PHP version) and Kyle Bragger (Ruby port)
and Lee Semel (python port)
Usage:
obfuscated_id = to_tiny(123)
original_id = from_tiny(obfuscated_id)
Configuration:
You must run generate_set() from console (using python tiny.py) to generate your $set
Do *not* change this once you start using Tiny, as you won't be able to from_tiny()
any values to_tiny()'ed with another set.
"""
import random
SET = 'poygezRY9L1x8CTl6rUBKQHwVuIkh4fZ7cv3sdJaAjO2iqWbFt0nM5EPGSmDXN'
def to_tiny(id):
"""Converts from an integer to a tinified string."""
id = int(id)
hexn = ""
radix = len(SET)
while(True):
r = id % radix
hexn = SET[r] + hexn
id = (id - r) / radix
if (id == 0):
break
return hexn
def from_tiny(s):
"""Converts from a tinified string to an integer.
If any illegal characters are used in the string, return a -1.
These tiny urls are almost always used to look up a database item by
primary key, so this ensures that the database item is not found,
and a normal 404 page is thrown. If we instead threw an exception
we'd have a different exception to handle and the normal 404 page would
not be shown.
>>> from_tiny('abc_')
-1
>>> from_tiny('!!#$#$')
-1
>>> from_tiny('')
0
"""
radix = len(SET)
strlen = len(s)
n = 0
i = 0
while (i < strlen):
p = SET.find(s[i])
if (p < 0):
return -1
c = p * pow(radix, strlen - i - 1)
n += c
i += 1
return n
def generate_set():
"""Generates a new random set to be used for encoding.
The set will contain the uppercase and lowercase letters a-z and digits 0-9.
>>> set = generate_set()
>>> len(set)
62
>>> ok = True
>>> seen = {}
>>> "".join(sorted(set))
'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
>>> for i in range(0,100000):
... t = to_tiny(i)
... if (t in seen or len(t) == 0):
... ok = False
... seen[t] = i
... f = from_tiny(t)
... if (f != i):
... ok = False
...
>>> ok
True
"""
arr = []
for i in range(0,10):
arr.append(str(i))
for i in range(65,123):
if i < 91 or i > 96:
arr.append(chr(i))
random.shuffle(arr)
return "".join(arr)
if __name__=="__main__":
import doctest
doctest.testmod()
print(generate_set())
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