Support `@default` on payloads?
kubukoz opened this issue · comments
This may be controversial...
I think @default should be used on payloads, i.e. if the HTTP request/response body is empty, we should attempt to decode it from something like defaultValue.orElse(emptyObject).
It appears that we're currently only trying to decode from an empty body:
(this is from a reproduction posted below)
[info] 400 Bad Request: Succeeded: {"payload":{"path":".","expected":"string","message":"expected '\"', offset: 0x00000000, buf:\n+----------+-------------------------------------------------+------------------+\n| | 0 1 2 3 4 5 6 7 8 9 a b c d e f | 0123456789abcdef |\n+----------+-------------------------------------------------+------------------+\n| 00000000 | 7b 7d | {} |\n+----------+-------------------------------------------------+------------------+"}}
[info] DEBUG: Errored: HttpPayloadError(., expected = string, message=expected '"', offset: 0x00000000, buf:
[info] +----------+-------------------------------------------------+------------------+
[info] | | 0 1 2 3 4 5 6 7 8 9 a b c d e f | 0123456789abcdef |
[info] +----------+-------------------------------------------------+------------------+
[info] | 00000000 | 7b 7d | {} |
[info] +----------+-------------------------------------------------+------------------+)
To reproduce:
$version: "2"
namespace hello
use alloy#simpleRestJson
@simpleRestJson
service WeatherService {
operations: [PostWeather]
}
@http(method: "POST", uri: "/weather")
operation PostWeather {
input := {
@required
@httpPayload
city: String = "strange town"
}
output := {
@httpPayload
weather: String = "good weather"
}
}
package hello
import cats.effect.IO
import cats.effect.IOApp
import hello.WeatherService
import org.http4s.HttpApp
import org.http4s.Method
import org.http4s.Request
import org.http4s.Response
import org.http4s.client.Client
import org.http4s.ember.client.EmberClientBuilder
import org.http4s.ember.server.EmberServerBuilder
import smithy4s.http4s.SimpleRestJsonBuilder
object Main extends IOApp.Simple {
def serverDemo = SimpleRestJsonBuilder
.routes(
new WeatherService.Default[IO](IO.stub) {}: WeatherService[IO]
)
.resource
.flatMap { routes =>
EmberServerBuilder
.default[IO]
.withHttpApp(routes.orNotFound)
.build
}
.use { server =>
EmberClientBuilder.default[IO].build.use { client =>
client
.run(
Request[IO](method = Method.POST, uri = server.baseUri / "weather")
)
.use { response =>
response.bodyText.compile.string
.debug(response.status.toString())
.void
}
}
}
.void
def clientDemo = SimpleRestJsonBuilder(WeatherService)
.client(
Client.fromHttpApp(HttpApp.pure[IO](Response[IO]()))
)
.resource
.use(_.postWeather("NYC"))
.debug()
.attempt
.void
def run = serverDemo *> clientDemo
}
Full repro: https://github.com/kubukoz/demos/tree/smithy4s-required-payloads
I think this is the part responsible for the {} in the hexdump:
Update: a trivial "fix" proves that:
diff --git a/modules/json/src/smithy4s/json/internals/JsonPayloadCodecCompilerImpl.scala b/modules/json/src/smithy4s/json/internals/JsonPayloadCodecCompilerImpl.scala
index c02450ed8..b9b6c2f9b 100644
--- a/modules/json/src/smithy4s/json/internals/JsonPayloadCodecCompilerImpl.scala
+++ b/modules/json/src/smithy4s/json/internals/JsonPayloadCodecCompilerImpl.scala
@@ -71,19 +71,22 @@ private[json] case class JsonPayloadCodecCompilerImpl(
def fromSchema[A](schema: Schema[A], cache: Cache): PayloadDecoder[A] = {
val jcodec = jsoniterCodecCompiler.fromSchema(schema, cache)
- new JsonPayloadDecoder(jcodec)
+ new JsonPayloadDecoder(jcodec, schema.getDefaultValue)
}
def fromSchema[A](schema: Schema[A]): PayloadDecoder[A] =
fromSchema(schema, createCache())
}
- private class JsonPayloadDecoder[A](jcodec: JsonCodec[A])
+ private class JsonPayloadDecoder[A](jcodec: JsonCodec[A], default: Option[A])
extends PayloadDecoder[A] {
def decode(blob: Blob): Either[PayloadError, A] = {
try {
Right {
- if (blob.isEmpty) readFromString("{}", jsoniterReaderConfig)(jcodec)
+ if (blob.isEmpty)
+ default.getOrElse(
+ readFromString("{}", jsoniterReaderConfig)(jcodec)
+ )
else
blob match {
case b: Blob.ArraySliceBlob =>
so the question remains: is this something we should support?
Why not. PR away
@kubukoz I will take a look at it. Can you assign me?