KTOR - Unzip file in POST routing - kotlin

Question

I want to unzip a file zip sent within the body of a http query (content type: application/x-gzip) in Ktor (bloc rounting).
I've tried this:
val zip_received=call.receiveStream()
val incomingContent = GZIPInputStream(zip_received).toByteReadChannel()
But I got this error:
java.lang.IllegalStateException: Acquiring blocking primitives on this dispatcher is not allowed. Consider using async channel or doing withContext(Dispatchers.IO) { call.receive().use { ... } } instead.
I'm not able to write such function.
Can I have some helps ?
Thanks

Answer 1

You can use the following code to read GZip uncompressed request body as string:
import io.ktor.server.engine.*
import io.ktor.server.netty.*
import io.ktor.application.*
import io.ktor.request.*
import io.ktor.routing.*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
import java.io.InputStream
import java.util.zip.GZIPInputStream
fun main(args: Array<String>) {
embeddedServer(Netty, port = 9090) {
routing {
post("/") {
withContext(Dispatchers.IO) {
call.receive<InputStream>().use { stream ->
val gzipStream = GZIPInputStream(stream)
val uncompressedBody = String(gzipStream.readAllBytes())
println(uncompressedBody)
}
}
}
}
}.start()
}