Pass Dream.error object to error templates

Resolves aantron#162.

docs/web/postprocess/index.ml

@@ -1229,13 +1229,13 @@ let initialize_log_replacement = {|
 </pre>|}
 
 let error_template_expected = {|<div class="spec value" id="val-error_template">
- <a href="#val-error_template" class="anchor"></a><code><span><span class="keyword">val</span> error_template : <span><span>(<span><span>string option</span> <span class="arrow">-&gt;</span></span> <span><a href="#type-response">response</a> <span class="arrow">-&gt;</span></span> <span><a href="#type-response">response</a> <a href="#type-promise">promise</a></span>)</span> <span class="arrow">-&gt;</span></span> <a href="#type-error_handler">error_handler</a></span></code>
+ <a href="#val-error_template" class="anchor"></a><code><span><span class="keyword">val</span> error_template : <span><span>(<span><a href="#type-error">error</a> <span class="arrow">-&gt;</span></span> <span><span>string option</span> <span class="arrow">-&gt;</span></span> <span><a href="#type-response">response</a> <span class="arrow">-&gt;</span></span> <span><a href="#type-response">response</a> <a href="#type-promise">promise</a></span>)</span> <span class="arrow">-&gt;</span></span> <a href="#type-error_handler">error_handler</a></span></code>
 </div>
 |}
 
 let error_template_replacement = {|
 <pre><span class="keyword">val</span> error_template :
-  (string option -> <a href="#val-response">response</a> -> <a href="#val-response">response</a> <a href="#type-promise">promise</a>) ->
+  (<a href="#type-error">error</a> -> string option -> <a href="#val-response">response</a> -> <a href="#val-response">response</a> <a href="#type-promise">promise</a>) ->
     <a href="#type-error_handler">error_handler</a>
 </pre>
 |}

example/9-error/error.eml.ml

@@ -1,4 +1,4 @@
-let my_error_template debug_info suggested_response =
+let my_error_template _error debug_info suggested_response =
   let status = Dream.status suggested_response in
   let code = Dream.status_to_int status
   and reason = Dream.status_to_string status in

src/dream.mli

@@ -1887,14 +1887,14 @@ type error_handler = error -> response option promise
     {!Dream.type-error}. *)
 
 val error_template :
-  (string option -> response -> response promise) -> error_handler
+  (error -> string option -> response -> response promise) -> error_handler
 (** Builds an {!error_handler} from a template. See example
     {{:https://github.com/aantron/dream/tree/master/example/9-error#files}
     [9-error]} \[{{:http://dream.as/9-error} playground}\].
 
     {[
       let my_error_handler =
-        Dream.error_template (fun ~debug_dump suggested_response ->
+        Dream.error_template (fun _error debug_dump suggested_response ->
           let body =
             match debug_dump with
             | Some string -> Dream.html_escape string

src/http/error_handler.ml

@@ -183,12 +183,12 @@ let customize template (error : Dream.error) =
        site of the error handler already has error handlers for catching double
        faults. *)
     response
-    |> template debug_dump
+    |> template error debug_dump
     |> Lwt.map (fun response -> Some response)
 
 
 
-let default_template debug_dump response =
+let default_template _error debug_dump response =
   match debug_dump with
   | None -> Lwt.return response
   | Some debug_dump ->

src/http/error_handler.mli

@@ -14,7 +14,7 @@ module Dream = Dream__pure.Inmost
 
 val default : Dream.error_handler
 val customize :
-  (string option -> Dream.response -> Dream.response Lwt.t) ->
+  (Dream.error -> string option -> Dream.response -> Dream.response Lwt.t) ->
     Dream.error_handler