Module Vif.MiddlewaresSource

Middlewares.

Middleware is a function fn that applies to all requests. The user can introspect the headers (and only the headers) of the requests in order to add information (such as the connected user if a field in the headers provides such information). This information added to the request can be retrieved from the request handlers via Request.get.

Here is an example of middleware confirming client authentication via the "Authorization" field:

let ( let* ) = Option.bind

let decode str =
  match String.split_on_char ' ' str with
  | [ "Basic"; b64 ] ->
      let data = Base64.decode b64 in
      let* data = Result.to_option data in
      let data = String.split_on_char ':' data in
      let username = List.hd data and password = List.tl data in
      let password = String.concat ":" password in
      Some (username, password)
  | _ -> None

let auth =
  Vif.Middlewares.v ~name:"auth" @@ fun req _target _server _ ->
  let hdrs = Vif.Request.headers_of_request req in
  let* value = Vif.Headers.get hdrs "Authorization" in
  let* username, password = decode value in
  Some (username, password)

let () =
  Miou_unix.run @@ fun () ->
  let middlewares = Vif.Middlewares.[ auth ] in
  Vif.run ~middlewares routes ()