unikernel/duniverse/ocaml-h2/examples/lwt/lwt_get.ml

@@ -0,0 +1,61 @@
+open H2
+module Client = H2_lwt_unix.Client
+
+let response_handler notify_response_received _response response_body =
+  let rec read_response () =
+    Body.Reader.schedule_read
+      response_body
+      ~on_eof:(fun () -> Lwt.wakeup_later notify_response_received ())
+      ~on_read:(fun bigstring ~off ~len ->
+        let response_fragment = Bytes.create len in
+        Bigstringaf.blit_to_bytes
+          bigstring
+          ~src_off:off
+          response_fragment
+          ~dst_off:0
+          ~len;
+        print_string (Bytes.to_string response_fragment);
+        read_response ())
+  in
+  read_response ()
+
+let error_handler _ = assert false
+
+open Lwt.Infix
+
+let () =
+  let host = ref None in
+  let port = ref 443 in
+  Arg.parse
+    [ "-p", Set_int port, " Port number (443 by default)" ]
+    (fun host_argument -> host := Some host_argument)
+    "lwt_get.exe [-p N] HOST";
+  let host =
+    match !host with
+    | None -> failwith "No hostname provided"
+    | Some host -> host
+  in
+  Lwt_main.run
+    ( Lwt_unix.getaddrinfo
+        host
+        (string_of_int !port)
+        [ Unix.(AI_FAMILY PF_INET) ]
+    >>= fun addresses ->
+      let socket = Lwt_unix.socket Unix.PF_INET Unix.SOCK_STREAM 0 in
+      Lwt_unix.connect socket (List.hd addresses).Unix.ai_addr >>= fun () ->
+      let request =
+        Request.create
+          `GET
+          "/"
+          ~scheme:"https"
+          ~headers:Headers.(add_list empty [ ":authority", host ])
+      in
+      let response_received, notify_response_received = Lwt.wait () in
+      let response_handler = response_handler notify_response_received in
+      Client.SSL.create_connection_with_default ~error_handler socket
+      >>= fun connection ->
+      let request_body =
+        Client.SSL.request connection request ~error_handler ~response_handler
+      in
+      Body.Writer.close request_body;
+      response_received )