API v14 / New Parser Library / Kotlin

[dbrgn]

Last week we released v14 of the SpaceAPI schema! https://github.com/SpaceApi/schema/blob/master/MIGRATION.md

To support this, I'd like to rewrite the parser, which is currently using the (horrible!) Android JSON library.

I first took a look at https://app.quicktype.io/ and the generated source code. I like that it's based on Jackson, but it uses some Java 8 standard library functions that are not part of Android API21 and would need to be rewritten.

I thought about simplifying the generated code using plain Jackson calls, but that also seems quite a lot of work.

In the end, I saw that Kotlin has a new serialization framework that makes (de)serialization quite easy. I don't have much Kotlin experience, but it's definitely a nice language!

So TL;DR: Here's a new project I started, that should provide a standalone lenient Kotlin/Java parser for SpaceAPI endpoints. https://github.com/spaceapi-community/spaceapi-kt The goal is to have a single library / wrapper type that can parse both v0.13 and v14 endpoints (and future versions as well). The focus is on parsing, not on serializing, so we can skip a lot of validation logic.

Kotlin has nice Java interop, so Kotlin can call Java and vice versa. The only cost is that the Kotlin runtime needs to be integrated as a Gradle dependency, which makes the app a bit larger. On the other hand we then have the option of using Kotlin as well in the app code.

(Maybe it's also possible to convert the library into pure-JVM bytecode that does not require the Kotlin runtime, but I doubt it.)

@rorist do you see any problem with this approach? Would you accept a PR that replaces the parser with this library?

[dbrgn]

I tested the deserialization with a local JAR file and it already works 🙂 I plan to publish the spaceapi-kt library on Bintray though, then we can pull it in using Gradle.