How to make unique short URL with Python?

Question

How can I make unique URL in Python a la http://imgur.com/gM19g or http://tumblr.com/xzh3bi25y When using uuid from python I get a very large one. I want something shorter f

Answer 1

You can generate a N random string:

import string
import random

def short_random_string(N:int) -> str:

    return ''.join(random.SystemRandom().choice(
                    string.ascii_uppercase + \
                    string.ascii_lowercase + \
                    string.digits) for _ in range(N))

so,

print (short_random_string(10) )
#'G1ZRbouk2U'

all lowercase

print (short_random_string(10).lower() )
#'pljh6kp328'

Answer 2

Try this http://code.google.com/p/tiny4py/ ... It's still under development, but very useful!!

Answer 3

Hashids is an awesome tool for this.

Edit:

Here's how to use Hashids to generate a unique short URL with Python:

from hashids import Hashids

pk = 123 # Your object's id
domain = 'imgur.com' # Your domain

hashids = Hashids(salt='this is my salt', min_length=6)
link_id = hashids.encode(pk)
url = 'http://{domain}/{link_id}'.format(domain=domain, link_id=link_id)

Answer 4

This module will do what you want, guaranteeing that the string is globally unique (it is a UUID):

http://pypi.python.org/pypi/shortuuid/0.1

If you need something shorter, you should be able to truncate it to the desired length and still get something that will reasonably probably avoid clashes.

Answer 5

My Goal: Generate a unique identifier of a specified fixed length consisting of the characters 0-9 and a-z. For example:

zcgst5od
9x2zgn0l
qa44sp0z
61vv1nl5
umpprkbt
ylg4lmcy
dec0lu1t
38mhd8i5
rx00yf0e
kc2qdc07

Here's my solution. (Adapted from this answer by kmkaplan.)

import random

class IDGenerator(object):
    ALPHABET = "0123456789abcdefghijklmnopqrstuvwxyz"

    def __init__(self, length=8):
        self._alphabet_length = len(self.ALPHABET)
        self._id_length = length

    def _encode_int(self, n):
        # Adapted from:
        #   Source: https://stackoverflow.com/a/561809/1497596
        #   Author: https://stackoverflow.com/users/50902/kmkaplan

        encoded = ''
        while n > 0:
            n, r = divmod(n, self._alphabet_length)
            encoded = self.ALPHABET[r] + encoded
        return encoded

    def generate_id(self):
        """Generate an ID without leading zeros.

        For example, for an ID that is eight characters in length, the
        returned values will range from '10000000' to 'zzzzzzzz'.
        """

        start = self._alphabet_length**(self._id_length - 1)
        end = self._alphabet_length**self._id_length - 1
        return self._encode_int(random.randint(start, end))

if __name__ == "__main__":
    # Sample usage: Generate ten IDs each eight characters in length.
    idgen = IDGenerator(8)

    for i in range(10):
        print idgen.generate_id()

Answer 6

The reason UUIDs are long is because they contain lots of information so that they can be guaranteed to be globally unique.

If you want something shorter, then you'll need to do something like generate a random string, checking whether it is in the universe of already generated strings, and repeating until you get an unused string. You'll also need to watch out for concurrency here (what if the same string gets generated by a separate process before you inserted into the set of strings?).

If you need some help generating random strings in Python, this other question might help.