ktor client post multipart/form-data

Question

How can I post file as multipart/form-data use ktor client? I want to use it for telegram bot API "send document". I need to achieve the same result as the curl command

curl -F document=@"path/to/some.file" https://api.telegram.org/bot<token>/sendDocument?chat_id=<chat_id>

Answer 1

You can use the submitFormWithBinaryData method to send mutlipart/form-data request. Here is a solution:

val client = HttpClient(Apache) {}

val file = File("path/to/some.file")
val chatId = "123"

client.submitFormWithBinaryData(
    url = "https://api.telegram.org/bot<token>/sendDocument?chat_id=$chatId",
    formData = formData {
        append("document", file.readBytes(), Headers.build {
            append(HttpHeaders.ContentDisposition, "filename=${file.name}")
        })
    }
)