Should the use of Body(.json) set the Content-Type accordingly automatically ?

[mackoj]

Hi,

If we use a Route like this one. Should the Content-Type be set automatically to application/json ?

  Route(.case(BuildRoute.abort)) {
    Method.post
    Body(.json(BuildRoute.BodyParameters.self))
  }

It remove this Headers { Field("Content-Type") { Parse { "application/json" } } }

  Route(.case(BuildRoute.abort)) {
    Headers { Field("Content-Type") { Parse { "application/json" } } }
    Method.post
    Body(.json(BuildRoute.BodyParameters.self))
  }

Thanks,

[stephencelis]

@mackoj I think there's definitely something to this. And FormData should probably set a header, too.

I think we probably don't want to be so strict with the parsing, though. Instead, we could use baseRequestData to prefer printing this header.

Body(.json(BuildRoute.BodyParameters.self))
// =
Body(.json(BuildRoute.BodyParameters.self))
  .baseRequestData(.init(headers: ["Content-Type": ["application/json"]]))

[mackoj]

Thanks for the tips I will use it instead of forcing it through the header.

[kamcma]

Glad to find this tip, as I was looking to solve the same thing. I cooked up a small helper to prevent sprinkling .baseRequestData()s across router code:

extension Body where Bytes: ParserPrinter {
  static func fooAPIJSONEncoded<Value: Codable>(_ type: Value.Type) -> BaseURLPrinter<Self>
  where Bytes == Parsers.MapConversion<Parsers.ReplaceError<Rest<Data>>, Conversions.JSON<Value>> {
    self.init(
      .json(
        type,
        decoder: fooAPIConfiguredDecoder,
        encoder: fooAPIConfiguredEncoder
      )
    )
    .baseRequestData(.init(headers: ["Content-Type": ["application/json"]]))
  }
}

You can then call like so:

Route(.case(FooAPI.someRouteWithFooAPICodableTypeBody)) {
  Method.post
  Body.fooAPIJSONEncoded(FooAPICodableType.self)
}

Open to suggestions to improve it further; I was mostly just following compiler complaints on the constraints. 🙂

[kamcma]

An alternative I pondered but am perhaps not slick enough to implement myself is some sort of higher-order router that would add the .baseRequestData to any case matching, eg, POST method and a JSON conversion body. Or something like that. I don't know if that's possible.