build.gradle

group 'org.example'
version '1.0-SNAPSHOT'

buildscript {
    ext {
        kotlin_version = 'latest.integration'
    }

    repositories {
        jcenter()
    }
    dependencies {
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

apply plugin: 'kotlin'
apply plugin: 'application'

mainClassName = 'MainKt'

repositories {
    jcenter()
}

allprojects {
    repositories {
        maven {
            url "https://jitpack.io"
        }
    }
}
dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
//    implementation "khttp:khttp:latest.integration"
    implementation "com.github.rtazaki:khttp:master-SNAPSHOT"
    implementation "com.github.kittinunf.fuel:fuel:latest.integration"
    implementation "com.fasterxml.jackson.module:jackson-module-kotlin:latest.integration"
}

example_path.py

from flask import Flask, request, jsonify

app = Flask(__name__)
app.config["JSON_AS_ASCII"] = False


@app.route("/test", methods=["POST"])
def test():
    if request.method == "POST":
        content_type = request.headers["Content-Type"]
        if content_type != "application/json":
            print(content_type)
            return jsonify({"cause": "ヘッダがJsonじゃない(content type error)"}), 400
        data = request.get_json()
        print(data)
        return data


@app.route("/contact", methods=["GET"])
def contact():
    if request.method == "GET":
        contents = request.args.get("value", "")
        print(contents)
        return contents


if __name__ == "__main__":
    app.run(debug=True, host="example_path", port=50000)

hosts

	127.0.0.1       example_path
	127.0.0.1       example-path
	

Main.kt

import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
import com.github.kittinunf.fuel.httpPost

fun main() {
    // khttpだと、怒られた
// => java.net.URISyntaxException: Illegal character in hostname at index 14: http://example_path:50000/test
    // => ローカルで試した対策版でFixしている。→プルリク済み。
    try {
        val post = khttp.post("http://example_path:50000/test",
                json = mapOf("name" to "rtazaki", "hobby" to "syogi"))
        println(post)
        // 追試: 日本語GET成功
        val get = khttp.get("http://example_path:50000/contact",
                params = mapOf("value" to "日本語"))
        println(get)
    } catch (e: Exception) {
        println(e)
    }
//    // fuelだとどうかな? → 問題ない。
//    val mapper = jacksonObjectMapper()
//    try {
//        val url = "http://example_path:50000/test"
//        val ret = url.httpPost()
//                .header(mapOf("Content-Type" to "application/json"))
//                .body(mapper.writeValueAsString(mapOf("name" to "rtazaki", "hobby" to "syogi")))
//                .response()
//        println(ret)
//    } catch (e: Exception) {
//        println(e)
//    }
    // 原因:
    // khttpだと、
    // ->GenericRequest.kt->URL.toIDN()->return URL(URI(..
    // で、URIでアンダーバーが使えないため、
    // java.net.URISyntaxException: Illegal character
    // となってしまうため。
    // JAVAだと絶対にダメではない。
    // fuelでは「URLをURIに」変換して回避している?
    // [参考]
    // https://stackoverflow.com/questions/28568188/java-net-uri-get-host-with-underscores
//    try {
//        val xx = "http://coder_1.tanglei.name"
//        val u = URI(xx)
//        println(u)
//        println(u.host) // null
//        val url = URL(xx)
//        println(url)
//        println(url.host) // coder_1.tanglei.name
//        val u2 = URI(url.protocol, url.host, url.path, "")
//        println(u2)
//    } catch (e: Exception) {
//        println("exception got: " + e.message)
//    }
// => exception got: Illegal character in hostname at index 12: http://coder_1.tanglei.name#
    // 回避策
//    val uriObj = URI("https://pmi_artifacts_prod.s3.amazonaws.com")
//    if (uriObj.host == null) {
//        val hostField = URI::class.java.getDeclaredField("host")
//        hostField.isAccessible = true
//        hostField.set(uriObj, "pmi_artifacts_prod.s3.amazonaws.com")
//    }
//    println(uriObj.host)
}