KotlinによるFuel HTTPライブラリ

<dependency>
    <groupId>com.github.kittinunf.fuel</groupId>
    <artifactId>fuel</artifactId>
    <version>${fuel.version}</version>
</dependency>
<dependency>
    <groupId>com.github.kittinunf.fuel</groupId>
    <artifactId>fuel-gson</artifactId>
    <version>${fuel.version}</version>
</dependency>
<dependency>
    <groupId>com.github.kittinunf.fuel</groupId>
    <artifactId>fuel-rxjava</artifactId>
    <version>${fuel.version}</version>
</dependency>
<dependency>
    <groupId>com.github.kittinunf.fuel</groupId>
    <artifactId>fuel-coroutines</artifactId>
    <version>${fuel.version}</version>
</dependency>

fun response(handler: (Request, Response, Result<ByteArray, FuelError>) -> Unit)
fun responseString(handler: (Request, Response, Result<String, FuelError>) -> Unit)
fun responseJson(handler: (Request, Response, Result<Json, FuelError>) -> Unit)
fun <T> responseObject(deserializer: ResponseDeserializable<T>,
  handler: (Request, Response, Result<T, FuelError>) -> Unit)

val (request, response, result) = Fuel.post("http://httpbin.org/post")
  .responseString()
val (payload, error) = result//payload is a String

<dependency>
    <groupId>com.github.kittinunf.fuel</groupId>
    <artifactId>fuel-android</artifactId>
    <version>${fuel.version}</version>
</dependency>

public fun deserialize(bytes: ByteArray): T?
public fun deserialize(inputStream: InputStream): T?
public fun deserialize(reader: Reader): T?
public fun deserialize(content: String): T?

data class Post(var userId:Int,
                var id:Int,
                var title:String,
                var body:String){

    class Deserializer : ResponseDeserializable<Array<Post>> {
        override fun deserialize(content: String): Array<Post>
          = Gson().fromJson(content, Array<Post>::class.java)
    }
}

"https://jsonplaceholder.typicode.com/posts"
  .httpGet().responseObject(Post.Deserializer()){
    __,__, result ->
      val postsArray = result.component1()
  }

"https://jsonplaceholder.typicode.com/posts/1"
  .httpGet().responseObject<Post> { __, __, result ->
    val post = result.component1()
  }

val post = Post(1, 1, "Lorem", "Lorem Ipse dolor sit amet")

val (request, response, result)
  = Fuel.post("https://jsonplaceholder.typicode.com/posts")
    .header("Content-Type" to "application/json")
    .body(Gson().toJson(post).toString())

sealed class PostRoutingAPI : FuelRouting {
    class posts(val userId: String, override val body: String?): PostRoutingAPI()
    class comments(val postId: String, override val body: String?): PostRoutingAPI()
    override val basePath = "https://jsonplaceholder.typicode.com"

    override val method: Method
        get() {
            return when(this) {
                is PostRoutingAPI.posts -> Method.GET
                is PostRoutingAPI.comments -> Method.GET
            }
        }

    override val path: String
        get() {
            return when(this) {
                is PostRoutingAPI.posts -> "/posts"
                is PostRoutingAPI.comments -> "/comments"
            }
        }

    override val params: List<Pair<String, Any?>>?
        get() {
            return when(this) {
                is PostRoutingAPI.posts -> listOf("userId" to this.userId)
                is PostRoutingAPI.comments -> listOf("postId" to this.postId)
            }
        }

    override val headers: Map<String, String>?
        get() {
            return null
        }
}

Fuel.request(PostRoutingAPI.posts("1",null))
  .responseObject(Post.Deserializer()) {
      request, response, result ->
       //response handling
  }

Fuel.request(PostRoutingAPI.comments("1",null))
  .responseString { request, response, result ->
     //response handling
  }