uuid-b64

A UUID wrapper that has a base64 display and serialization

What?

A newtype around UUIDs that:

• Displays and Serializes as Base64
  • Specifically it is the url-safe base64 variant, with no padding

let known_id = Uuid::parse_str("b0c1ee86-6f46-4f1b-8d8b-7849e75dbcee").unwrap();
let as_b64 = UuidB64::from(known_id);
assert_eq!(as_b64.to_string(), "sMHuhm9GTxuNi3hJ51287g");

let parsed_b64: UuidB64 = "sMHuhm9GTxuNi3hJ51287g".parse().unwrap();
assert_eq!(parsed_b64, as_b64);

let raw_id = Uuid::new_v4();
assert_eq!(raw_id.to_string().len(), 36);
let uuidb64 = UuidB64::from(raw_id);
assert_eq!(uuidb64.to_string().len(), 22);

UuidB64::new creates v4 UUIDs, because... that's what I use. I'm open to hearing arguments about why this is a ridiculous decision and I should have made new be new_v4.

Why?

UUIDs are great:

• They have a known size and representation, meaning that they are well-supported with an efficient representation in a wide variety of systems. Things like programming languages and databases.
• V4 (almost completely random) UUIDs have nice sharding properties, you can give out UUIDs willy-nilly without coordination and still be guaranteed to not have a conflict of IDs between two items across systems.

That said, the standard representation for UUIDs is kind of annoying:

• It's a long: 36 characters to represent 16 bytes of data!
• It's hard to read: it is only hexadecimal characters. The human eye needs to pay a lot of attention to be certain if any two UUIDs are the same.

I guess that's it. Base64 is a more human-friendly representation of UUIDs:

• It's slightly shorter: 1.375 times the size of the raw data (22 characters), vs 2.25 times the size characters.
• Since it is case-sensitive, the shape of the IDs helps to distinguish between different IDs. There is also more entropy per character, so scanning to find a difference is faster.

That said, there are drawbacks to something like this:

• If you store it as a UUID column in a database IDs won't show up in the same way as it does in your application code, meaning you'll (A) maybe want to define a new database type, or B just expect to only ever interact with the DB via you application.

  Conversion functions are pretty trivial, this works in postgres (inefficiently, but it's only for interactive queries so whatever):

  CREATE FUNCTION b64uuid(encoded TEXT) RETURNS UUID
  AS $$
      BEGIN
          RETURN ENCODE(DECODE(REPLACE(REPLACE(
              encoded, '-', '+'), '_', '/') || '==', 'base64'), 'hex')::UUID;
      END
  $$ LANGUAGE plpgsql;

Usage

Just use UuidB64 everywhere you would use Uuid, and use UuidB64::from to create one from an existing UUID.

Features

• serde enables serialization/deserialization via Serde.
• diesel-uuid enables integration with Diesel's UUID support, this is only tested on postgres, PRs welcome for other DBs.

Contributing

Testing

Most tests are standard: cargo test or cargo test --features serde, but if you want to test the diesel integration (the diesel-uuid feature) then we need a running postgres instance. Assuming that you have docker running locally and are in bash you can do ./run-tests.sh to execute all tests.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.