Decode from stream instead of string

[VincentJoshuaET]

class FromString(override val format: StringFormat) : Serializer() {
    override fun <T> fromResponseBody(loader: DeserializationStrategy<T>, body: ResponseBody): T {
      val string = body.string()
      return format.decodeFromString(loader, string)
    }

    override fun <T> toRequestBody(contentType: MediaType, saver: SerializationStrategy<T>, value: T): RequestBody {
      val string = format.encodeToString(saver, value)
      return RequestBody.create(contentType, string)
    }
  }

to

class FromStream(override val format: StringFormat) : Serializer() {
    override fun <T> fromResponseBody(loader: DeserializationStrategy<T>, body: ResponseBody): T {
      val stream = body.byteStream()
      return format.decodeFromStream(loader, stream)
    }

    override fun <T> toRequestBody(contentType: MediaType, saver: SerializationStrategy<T>, value: T): RequestBody {
      val stream = ByteArrayOutputStream()
      format.encodeToStream(saver, value, stream)
      return RequestBody.create(contentType, stream.toByteArray())
    }
  }

[JakeWharton]

I don't see much reason to change the encoding since both end up buffering. We can switch the decoding, however. Want to send a PR?

[JakeWharton]

This is blocked on:

• Streaming being available for all format types, not just a single one
• The streaming API being stable

[FunkyMuse]

This is blocked on:

* [ ]  Streaming being available for all format types, not just a single one

* [ ]  The streaming API being stable

Is there any update on this or where can we track this?

[JakeWharton]

On the kotlinx.serialization repo. I'm not sure if there are bugs for either, but you could create them.

[mthmulders]

I believe streaming support has landed in kotlinx.serialization 1.3.0: Kotlin/kotlinx.serialization#204.

[JakeWharton]

Yes, but only for JSON. This issue was filed after 1.3.0 was released.

[gajicm93]

@JakeWharton I see that 1.4.0 now supports Okio BufferedSource and BufferedSink. Is this converter gonna be updated with that or is Retrofit maybe planning on releasing an official converter? Thanks.

[JakeWharton]

No, nothing has really changed. Streaming still only works for JSON not all text formats. And the APIs this library uses are still marked as unstable which means we cannot upstream it yet.

[ahulyk]

@JakeWharton Will the usage of Okio BufferedSource and BufferedSink APIs reduce memory footprint during serialization/deserialization?

[JakeWharton]

If the response if absolutely huge it would, yes.

[ahulyk]

@JakeWharton cool, thanks

[ahulyk]

@JakeWharton we have stable kotlinx.serialization v1.4.0 could we expect the support of Okio in the near future?

[JakeWharton]

No. It's only supported for Json and not arbitrary StringFormats.

[JakeWharton]

I suppose we could add a Json-specific overload of the factory function for now to enable it.

[JakeWharton]

Although Json is in a separate library so it would require a separate artifact...

[AlexTrotsenko]

@JakeWharton given that you are considering separate artifact for JSON - do you think it is realistic to have an "official" retrofit-converter for JSON with kotlinx-serialization? As far as I see, JSON support seams to be stable in kotlinx-serialization now.

[JakeWharton]

No, the APIs we use are still unstable for any format.