highway

Highway allows you to define typed routes (whose query parameters are validated by Pidgin) that can:

• be used to generate links in a type-safe manner
• build services (controllers) and route them

open Highway

First let's define a few routes:

module Routes = struct
  let home = get [] ignore_params
  let hello = get [ s "hello" ] ignore_params
  let hello_to = get [ s "hello"; string ] (bool_opt_param "shout")
end

Next, we'll associate these routes with controllers by defining services:

module Services = struct
  let a_href route args params message =
    "<a href=\"" ^ html_href route args params ^ "\">" ^ message ^ "</a>"
  ;;

  let home =
    service ~context:no_context ~route:Routes.home (fun [] () () _request ->
      "Welcome to my website. Here is a page: "
      ^ a_href Routes.hello [] () "<button>Hello Page!</button>"
      ^ "and here is another page: "
      ^ a_href
          Routes.hello_to
          [ "Highway" ]
          (Some true)
          "<button>Hello to Highway!</button>")

  let hello =
    service ~context:no_context ~route:Routes.hello (fun [] () () _request ->
      "Hello, World... " ^ a_href Routes.home [] () "Back to home")

  let hello_to =
    service
      ~context:no_context
      ~route:Routes.hello_to
      (fun [ name ] shout () _request ->
         let is_shout = Option.value ~default:false shout in
         let name = if is_shout then String.uppercase_ascii name else name in
         "Hello " ^ name ^ "... " ^ a_href Routes.home [] () "Back to home")
end

And now we can route our various services:

let dispatch ~given_method ~given_path ~given_query_params () =
  dispatch
    ~given_method
    ~given_path
    ~given_query_params
    Services.[ home; hello; hello_to ]

Please refer to the documentation for the highway.mli module for more information.