Hashids is a small open-source library that generates short, unique, non-sequential ids from numbers. It converts numbers like 347 into strings like “yr8”. You can also decode those ids back. This is useful in bundling several parameters into one or simply using them as short UIDs.
You can use hashids to hide primary keys in your database. I've used the extension on several production databases.
Tested PostgreSQL versions : 9.5.X and 9.6.X (Should work on older versions, just not tested)
It's using hashids.c under the hood. More information about hashids and it's implementations here: hashids.org
Make sure you have development packages installed for postgres and build tools in general.
make; sudo make install
Then in a psql session issue:
CREATE extension pg_hashids;
Install as usual.
make; sudo make install
Then in a psql session issue:
ALTER EXTENSION pg_hashids UPDATE;
or
DROP EXTENSION pg_hashids;
CREATE EXTENSION pg_hashids;
Check
SELECT default_version, installed_version FROM pg_available_extensions WHERE name = 'pg_hashids';
Returns a hash using the default alphabet and empty salt.
SELECT id_encode(1001); -- Result: jNl
Returns a hash using the default alphabet and supplied salt.
SELECT id_encode(1234567, 'This is my salt'); -- Result: Pdzxp
Returns a hash using the default alphabet, salt and minimum hash length.
SELECT id_encode(1234567, 'This is my salt', 10); -- Result: PlRPdzxpR7
Returns a hash using the supplied alphabet, salt and minimum hash length.
SELECT id_encode(1234567, 'This is my salt', 10, 'abcdefghijABCDxFGHIJ1234567890'); -- Result: 3GJ956J9B9
You can also decode previouslt generated hashes. Just use the same salt, otherwise you'll get wrong results.
SELECT id_decode('PlRPdzxpR7', 'This is my salt', 10); -- Result: 1234567
Using a custom alphabet
SELECT id_decode('3GJ956J9B9', 'This is my salt', 10, 'abcdefghijABCDxFGHIJ1234567890'); -- Result: 1234567