do not force file to exist

src/app.ml

@@ -20,14 +20,13 @@ let config_dir =
 
 let config =
   let filename = Filename.concat config_dir "config.scfg" in
-  if not @@ Sys.file_exists filename then
-    failwith
-    @@ Format.sprintf "configuration file `%s` does not exist, please create it"
-         filename;
-  Dream.log "config file: %s" filename;
-  match Scfg.Parse.from_file filename with
-  | Error e -> failwith e
-  | Ok config -> config
+  if not @@ Sys.file_exists filename then []
+  else begin
+    Dream.log "config file: %s" filename;
+    match Scfg.Parse.from_file filename with
+    | Error e -> failwith e
+    | Ok config -> config
+  end
 
 let open_registration =
   match Scfg.Query.get_dir "open_registration" config with
@@ -59,8 +58,9 @@ let port =
 let () = Dream.log "port: %d" port
 
 let hostname =
+  let default_hostname = Format.sprintf "localhost:%d" port in
   match Scfg.Query.get_dir "hostname" config with
-  | None -> Format.sprintf "localhost:%d" port
+  | None -> default_hostname
   | Some hostname ->
     Result.fold ~error:failwith ~ok:Fun.id (Scfg.Query.get_param 0 hostname)
 
@@ -78,17 +78,15 @@ let log =
 
 let () = Dream.log "log: %b" log
 
-let get_dirs name =
-  let dirs = Scfg.Query.get_dirs name config in
-  List.map
-    (fun dir ->
-      Result.fold ~error:failwith ~ok:Fun.id (Scfg.Query.get_param 0 dir) )
-    dirs
-
 let random_state = Random.State.make_self_init ()
 
 let () = Random.set_state random_state
 
 let about =
-  (* TODO read from about.txt *)
-  "This is pellest"
+  let default_about = "Pellest is great !" in
+  match Scfg.Query.get_dir "about" config with
+  | None -> default_about
+  | Some about -> (
+    match Scfg.Query.get_param 0 about with
+    | Error e -> failwith e
+    | Ok about -> about )