From d81b1986b67ccf8024deeb3d1c223452116fdb4d Mon Sep 17 00:00:00 2001
From: Anton Bachin <antonbachin@yahoo.com>
Date: Mon, 13 Dec 2021 17:51:48 +0300
Subject: [PATCH] Delete per-server "global" variables as a concept

---
 example/4-counter/README.md |  8 --------
 src/dream.mli               | 15 +--------------
 src/http/error_handler.ml   | 20 ++++++++------------
 src/pure/dream_pure.mli     |  8 --------
 src/pure/inmost.ml          | 24 ------------------------
 5 files changed, 9 insertions(+), 66 deletions(-)

diff --git a/example/4-counter/README.md b/example/4-counter/README.md
index f65f3f3d..f976ed66 100644
--- a/example/4-counter/README.md
+++ b/example/4-counter/README.md
@@ -42,14 +42,6 @@ promise with [Lwt](https://github.com/ocsigen/lwt#readme), the promise library
 used by Dream. The next example, [**`5-promise`**](../5-promise#files), does
 exactly that!
 
-<!-- TODO
-<br>
-
-Advanced example [**`w-globals`**](../w-globals/#files) shows how to replace
-global state like `count` by state scoped to the application. This is useful if
-you are writing middleware to publish in a library. It's fine to use a global
-`ref` in private code!
--->
 <br>
 
 **Next steps:**
diff --git a/src/dream.mli b/src/dream.mli
index 424caf49..a23c5302 100644
--- a/src/dream.mli
+++ b/src/dream.mli
@@ -2290,14 +2290,11 @@ val decrypt :
 
 (** {1 Variables}
 
-    Dream provides two variable scopes for use by middlewares. *)
+    Dream supports user-defined per-message variables for use by middlewares. *)
 
 type 'a local
 (** Per-message variable. *)
 
-type 'a global
-(** Per-server variable. *)
-
 val new_local : ?name:string -> ?show_value:('a -> string) -> unit -> 'a local
 (** Declares a variable of type ['a] in all messages. The variable is initially
     unset in each message. The optional [~name] and [~show_value] are used by
@@ -2309,16 +2306,6 @@ val local : 'a local -> 'b message -> 'a option
 val with_local : 'a local -> 'a -> 'b message -> 'b message
 (** Sets the per-message variable to the value. *)
 
-val new_global :
-  ?name:string -> ?show_value:('a -> string) -> (unit -> 'a) -> 'a global
-(** Declares a variable of type ['a] in all servers. The first time the variable
-    is accessed, the given initializer function is called to get its value.
-    Global variables cannot be changed. So, they are typically refs or other
-    mutable data structures, such as hash tables. *)
-
-val global : 'a global -> request -> 'a
-(** Retrieves the value of the per-server variable. *)
-
 
 
 (** {1 Testing} *)
diff --git a/src/http/error_handler.ml b/src/http/error_handler.ml
index d6a4cd0e..04178541 100644
--- a/src/http/error_handler.ml
+++ b/src/http/error_handler.ml
@@ -94,18 +94,14 @@ let dump (error : Dream.error) =
     Dream.all_headers last
     |> List.iter (fun (name, value) -> p "\n%s: %s" name value);
 
-    let show_variables kind =
-      kind (fun name value first ->
-        if first then
-          p "\n";
-        p "\n%s: %s" name value;
-        false)
-        true
-        request
-      |> ignore
-    in
-    show_variables Dream.fold_locals;
-    show_variables Dream.fold_globals
+    Dream.fold_locals (fun name value first ->
+      if first then
+        p "\n";
+      p "\n%s: %s" name value;
+      false)
+      true
+      request
+    |> ignore
   end;
 
   Buffer.contents buffer
diff --git a/src/pure/dream_pure.mli b/src/pure/dream_pure.mli
index 95ec6e1e..ed8fbcb0 100644
--- a/src/pure/dream_pure.mli
+++ b/src/pure/dream_pure.mli
@@ -453,14 +453,6 @@ val local : 'a local -> 'b message -> 'a option
 val with_local : 'a local -> 'a -> 'b message -> 'b message
 val fold_locals : (string -> string -> 'a -> 'a) -> 'a -> 'b message -> 'a
 
-type 'a global
-val new_global :
-  ?name:string -> ?show_value:('a -> string) -> (unit -> 'a) -> 'a global
-val global : 'a global -> request -> 'a
-(* TODO Get rid of globals completely as a concept, once the site_prefix
-   middleware is clarified. *)
-val fold_globals : (string -> string -> 'a -> 'a) -> 'a -> request -> 'a
-
 
 
 (* TODO Delete once requests are mutable. *)
diff --git a/src/pure/inmost.ml b/src/pure/inmost.ml
index 4e712a7c..57e5dc07 100644
--- a/src/pure/inmost.ml
+++ b/src/pure/inmost.ml
@@ -70,7 +70,6 @@ and server = {
 }
 
 and app = {
-  globals : Scope.t ref;
   mutable app_debug : bool;
   mutable https : bool;
   mutable secrets : string list;
@@ -142,7 +141,6 @@ let site_prefix request =
   request.specific.app.site_prefix
 
 let new_app error_handler site_prefix = {
-  globals = ref Scope.empty;
   app_debug = false;
   https = false;
   secrets = [];
@@ -427,28 +425,6 @@ let with_local key value message =
 let fold_locals f initial message =
   fold_scope f initial message.locals
 
-type 'a global = {
-  key : 'a Scope.key;
-  initializer_ : unit -> 'a;
-}
-
-let new_global ?name ?show_value initializer_ = {
-  key = Scope.Key.create (name, show_value);
-  initializer_;
-}
-
-let global {key; initializer_} request =
-  match Scope.find key !(request.specific.app.globals) with
-  | Some value -> value
-  | None ->
-    let value = initializer_ () in
-    request.specific.app.globals :=
-      Scope.add key value !(request.specific.app.globals);
-    value
-
-let fold_globals f initial request =
-  fold_scope f initial !(request.specific.app.globals)
-
 let app request =
   request.specific.app