How do you get from the value on the left to the value on the right?
| UUID | ? |
|---|---|
| 2126816c-89f5-4aab-842f-65b9f3a39c8b | 56qHyeZvHYZitUFukWo5rz |
| 8b9f9c44-6e1b-485b-af00-c8b0e0067d59 | ieZJYUFB83oQacsNiQ55Bt |
| 72bd4bd2-9538-43f3-81b2-b8df991a32d8 | faLTidGsoG1G1TPLKUFcJh |
It’s not hex to base64 or hex to base58. That’s when I gave up and decided to comradesource it.
Context
PeerTube creates two URLs for each video. The original, long one looks like this:
https://tankie.tube/videos/watch/2126816c-89f5-4aab-842f-65b9f3a39c8b
And the sleeker format looks like this:
https://tankie.tube/w/faLTidGsoG1G1TPLKUFcJh
The database only stores the UUID so the shorter ID must be a function of the first.
It is int to base58. uuidToShort is the function, calling fromUUID from short-uuid.
There are multiple base58 implementations and I think this is the one bitcoin doesn’t use, which might make an online base58 translator get it wrong. short-uuid calls it “flickrBase58.”
This gets the correct answers:
def b58encode(fid):
CHARS = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ'
CHAR_NUM = len(CHARS)
encoded = ''
fid = int(fid)
while fid >= CHAR_NUM:
div, mod = divmod(fid, CHAR_NUM)
encoded = CHARS[mod] + encoded
fid = div
return CHARS[fid] + encoded
In [2]: b58encode(0x2126816c89f54aab842f65b9f3a39c8b)
Out[2]: '56qHyeZvHYZitUFukWo5rz'
In [3]: b58encode(0x8b9f9c446e1b485baf00c8b0e0067d59)
Out[3]: 'ieZJYUFB83oQacsNiQ55Bt'
In [4]: b58encode(0x72bd4bd2953843f381b2b8df991a32d8)
Out[4]: 'faLTidGsoG1G1TPLKUFcJh'
