Http_async doesn't ship with a router. There are multiple routing libraries available on opam and using Http_async with them should be fairly easy. As an example, integration with ocaml-dispatch can be done as so:
open! Core
open! Async
open Http_async
let routes =
let open Dispatch in
DSL.create
[ ( "/hello/:name"
, fun params _rest ->
let name = List.Assoc.find_exn params ~equal:String.equal "name" in
return (Response.create `Ok, Body.Writer.string (sprintf "Hello, %s" name)) )
; ("/", fun _params _rest -> Response.create `Ok, Body.Writer.string "Hello World")
]
;;
let service _addr (request, body) =
let path = Request.path request in
match Dispatch.dispatch routes path with
| Some response -> response
| None -> return (Response.create `Not_found, Body.Writer.string "Route not found")
;;
let () = Command_unix.run (Server.run_command ~summary:"Hello world HTTP Server" service)