I have following example which works well using curl:

curl -X 'POST' 
  'https://example.com/rest/someservice?oauth_token=<token>' 
  -H 'accept: application/json' 
  -H 'Content-Type: multipart/form-data' 
  -F 'file=@docs_recognize_ok.jpg;type=image/jpeg' 
  -F 'meta={
  "images": [
    {
      "name": "file"
    }
  ]
}'

Can’t figure out how to handle it using ktor client in Java/Kotlin?

For the moment I’m trying to handle it as:

        val json = "{n" +
                "  "images": [n" +
                "    {n" +
                "      "name": "file"n" +
                "    }n" +
                "  ]n" +
                "}"
        val filesList = mutableListOf<PartData>()
        val partData = formData {
            append(key = "meta", value = json, headers = Headers.build {
                append(HttpHeaders.ContentType, "application/json; charset=utf-8")
            })
            request.images.forEach { file ->
                append(
                    "file",
                    InputProvider { File(file.imageFileName).inputStream().asInput() },
                    Headers.build {
                        append(HttpHeaders.ContentType, "image/jpeg")
                    }
                )
            }
        }
        filesList.addAll(partData)
        httpClient.post("rest/someservice") {
            setBody(MultiPartFormDataContent(parts = filesList))
            parameters {
                append("oauth_token", apiKey)
            }
        }

Any ideas?