Server in Nim

server.nim

import asynchttpserver, asyncdispatch, json

var server = newAsyncHttpServer()

proc handler(req: Request) {.async.} =
    case req.url.path:
        of "/hello-world":
            let msg = %* {"message": "Hello World"}
            let headers = newHttpHeaders([
                ("Content-Type","application/json"),
                ("Access-Control-Allow-Origin","*")
            ])
            await req.respond(Http200, $msg, headers)
        else:
            await req.respond(Http404, "Not Found")

echo "Listening on port 4000"
waitFor server.serve(Port(4000), handler)