Handle byte string format according to specification

[hanny24]

Contributing to Twilio

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[blast-hardcheese]

https://swagger.io/docs/specification/data-models/data-types/#format seems to suggest this needs to be a base64-encoded string. There was OAI/OpenAPI-Specification#50 as well, discussing the semantics.

Perhaps we could generate a Base64 in order to explicitly control how the data is decoded?

[hanny24]

What class do you mean? AFAIK java's Base64 class contains only encoder and decoders from Array[Byte] and String

[blast-hardcheese]

I'm suggesting similar to how Part works for form data parts, where we'd have a

class Base64String(val value: String) extends AnyVal
object Base64String {
  implicit val encode: Encoder[Base64String] =
    Encoder[String].contramap[Base64String](a =>
      new String(java.util.Base64.getEncoder().encode(a.value.getBytes()))
    )
  implicit val decode: Decoder[Base64String] =
    Decoder[String].map[Base64String](a =>
      new Base64String(new String(java.util.Base64.getDecoder().decode(a)))
    )
}

that would make it extremely clear what the expectation of the String is as it is passed through the encoding implicit infrastructure.

The motivation here is to explicitly state the set of expectations internally, if not even explicitly exposed to consumers of guardrail, to communicate that type: string, format: byte actually does enforce some potentially unexpected encoding semantics instead of being surprising. The amount of discussion around this particular feature seems to suggest that this is a source of confusion for many, and communicating the semantics via types seems to be useful here.

Open to discussion, just putting ideas forward.

[hanny24]

So I added Base64String inside Implicits object. Not sure if it's the best place for it.

[hanny24]

I can see you did some changes. How can I help you to move this forward?

[blast-hardcheese]

@hanny24 The nudge was appreciated, just rebased and force-pushed the reformatted branch -- let's see how far it gets.

[blast-hardcheese]

Thanks again for your contribution and patience

[tomasherman]

hey @blast-hardcheese, would it be possible to release guardrail with this code?

[blast-hardcheese]

Can do, thanks for your patience!

[tomasherman]

no worries