Simple extension to use Codable JSON with Vapor 2

DemoModels.swift

import Foundation

struct MagicTestRequest: Codable {
    let tokens: [String]
}

struct MagicTestResponse: Codable {
    let count: Int
}

Encodable+Response.swift

import Foundation
import HTTP

extension Encodable {
    func makeResponse(using encoder: JSONEncoder = JSONEncoder(),
                      status: Status = .ok,
                      contentType: String = "application/json",
                      extraHeaders: [HeaderKey: String] = [:]) throws -> Response {
        let response = Response(status: status)
        response.headers = extraHeaders
        response.headers[.contentType] = contentType
        let data = try encoder.encode(self)
        response.body = Body.data(data.makeBytes())
        return response
    }
}

Message+Codable.swift

import Foundation
import HTTP

extension HTTP.Message {
    func decodeJSON<T: Decodable>(using decoder: JSONDecoder = JSONDecoder()) throws -> T {
        return try decoder.decode(T.self, from: Data(bytes: body.bytes ?? []))
    }
}

Routes.swift

import Vapor

extension Droplet {
    func setupRoutes() throws {
        post("magic") { req in
            guard let test: MagicTestRequest = try? req.decodeJSON() else {
                throw Abort.badRequest
            }

            return MagicTestResponse(count: test.tokens.count).makeResponse()
        }
    }
}