fuel is ~22x slower than java.net.http.HttpClient

Fuel seems to be very slow when sending a sending a request in its body. This is even more pronounced when the payload gets bigger (> 1MB). When benchmarked against the java.net.http.HttpClient, I noticed that fuel is 24 times slower than the http client that came with Java 11. This is the code I used to do a simple benchmark.

import com.github.kittinunf.fuel.httpPost
import java.net.URI
import java.net.http.HttpClient
import java.net.http.HttpRequest
import java.net.http.HttpResponse
import java.nio.file.Files
import java.nio.file.Paths

fun main() {
    val payload = Files.readString(Paths.get("large.json"))
    val url = "http://localhost:4567/lol"

    // fuel client
    val t = dumbBenchmark {
      url.httpPost().body(payload).response()
    }
    println("fuel client took $t ms on average")

    // java.net.http.HttpClient
    val client = HttpClient.newHttpClient()
    val req = HttpRequest.newBuilder()
        .uri(URI(url))
        .POST(HttpRequest.BodyPublishers.ofString(payload))
        .setHeader("Content-Type", "application/json")
        .build()

    val t2 = dumbBenchmark {
        client.send(req, HttpResponse.BodyHandlers.ofString())
    }
    println("httpclient took $t2 ms on average")
}

// Runs the lambda five times, time each invocation, and return the average  
fun dumbBenchmark(f: () -> Unit): Double = (1..5).map {
    val start = System.currentTimeMillis()
    f.invoke()
    val end = System.currentTimeMillis()
    end - start
}.average()

Here I am running a local sinatra server at localhost:4567, the server simply returns 200 OK for any kind of input. When I send a payload of ~2.2MB I get these results:

fuel client took 7488.2 ms on average
httpclient took 330.2 ms on average

I suspect this is due to the bufferring of the ProgressOutputStream in HttpClient.kt. I find it odd that even on a request that do not need progress reporting, fuel would still buffer the output stream. We should probably not buffer when a progress callback is not given to the request.

[tfactor2]

could it be done (pull request created) in scope of this issue?

[jsyeo]

fuel client took 528.2 ms on average
httpclient took 427.8 ms on average

Here you go!