Use product version as etag to reload index.html

This is a temporary change where the eTag check is invokved
from the boostrap.js .. but this logic should be on its own
javascript file.

Author: MarcialRosales

deps/rabbitmq_management/priv/www/index.html

@@ -21,9 +21,8 @@
     <link href="css/main.css" rel="stylesheet" type="text/css"/>
     <link href="favicon.ico" rel="shortcut icon" type="image/x-icon"/>    
 
-    <script type="module">
-      window.oauth = oauth_initialize_if_required()
-      
+    <script type="module">      
+      window.oauth = oauth_initialize_if_required()      
     </script>
 
 

deps/rabbitmq_management/priv/www/js/main.js

@@ -1862,3 +1862,11 @@ function get_chart_range_type(arg) {
     console.log('[WARNING]: range type not found for arg: ' + arg);
     return 'basic';
 }
+
+function check_etag(etag) {
+    lastEtag = get_pref('etag')    
+    if (!lastEtag || lastEtag != etag) {
+        store_pref('etag', etag)
+        location.reload()
+    }
+}

deps/rabbitmq_management/src/rabbit_mgmt_oauth_bootstrap.erl

@@ -19,12 +19,21 @@ bootstrap_oauth(Req0, State) ->
     AuthSettings = rabbit_mgmt_wm_auth:authSettings(),
     Dependencies = oauth_dependencies(),
     JSContent = import_dependencies(Dependencies) ++ 
+                check_etag() ++
                 set_oauth_settings(AuthSettings) ++ 
                 set_token_auth(AuthSettings, Req0) ++ 
                 export_dependencies(Dependencies),                
     {ok, cowboy_req:reply(200, #{<<"content-type">> => <<"text/javascript; charset=utf-8">>}, 
         JSContent, Req0), State}.
 
+check_etag() ->    
+    ETag = case {rabbit:product_name(), rabbit:product_version()} of
+        {undefined, _} -> rabbit:base_product_version();
+        {_, undefined} -> rabbit:base_product_version();
+        {_,_} -> rabbit:product_name() ++ " " ++ rabbit:product_version()
+    end,
+    ["check_etag('" ++ ETag ++ "');"].
+
 set_oauth_settings(AuthSettings) ->    
     JsonAuthSettings = rabbit_json:encode(rabbit_mgmt_format:format_nulls(AuthSettings)),
     ["set_oauth_settings(", JsonAuthSettings, ");"].