Рефакторинг админских обработчиков - пагинация, сортировка, фильтрация. Часть 1

src/handlers/admin/admin_handler_subscriptions.erl

@@ -5,7 +5,6 @@
 %%%-------------------------------------------------------------------
 -module(admin_handler_subscriptions).
 -behaviour(cowboy_handler).
-
 -export([init/2]).
 -export([trails/0]).
 
@@ -15,28 +14,28 @@
 init(Req, _Opts) ->
   case cowboy_req:method(Req) of
     <<"GET">> -> list_subscriptions(Req);
-    _         -> handler_utils:send_error(Req, 405, <<"Method not allowed">>)
+    _ -> handler_utils:send_error(Req, 405, <<"Method not allowed">>)
   end.
 
 -spec trails() -> [map()].
 trails() ->
   [
     #{
-      path        => <<"/v1/admin/subscriptions">>,
-      method      => <<"GET">>,
+      path => <<"/v1/admin/subscriptions">>,
+      method => <<"GET">>,
       description => <<"List all subscriptions (admin)">>,
-      tags        => [<<"Subscriptions">>],
-      parameters  => [
-        #{name => <<"plan">>,   in => <<"query">>, schema => #{type => string, enum => [<<"monthly">>, <<"quarterly">>, <<"biannual">>, <<"annual">>]}, description => <<"Filter by plan">>},
+      tags => [<<"Subscriptions">>],
+      parameters => [
+        #{name => <<"plan">>, in => <<"query">>, schema => #{type => string, enum => [<<"monthly">>, <<"quarterly">>, <<"biannual">>, <<"annual">>]}, description => <<"Filter by plan">>},
         #{name => <<"status">>, in => <<"query">>, schema => #{type => string, enum => [<<"active">>, <<"expired">>, <<"cancelled">>]}, description => <<"Filter by status">>},
-        #{name => <<"limit">>,  in => <<"query">>, schema => #{type => integer}, description => <<"Page size">>},
+        #{name => <<"limit">>, in => <<"query">>, schema => #{type => integer}, description => <<"Page size">>},
         #{name => <<"offset">>, in => <<"query">>, schema => #{type => integer}, description => <<"Offset">>}
       ],
       responses => #{
         200 => #{
           description => <<"Array of subscriptions">>,
           content => #{<<"application/json">> => #{schema => #{
-            type  => array,
+            type => array,
             items => subscription_schema()
           }}}
         }
@@ -46,17 +45,17 @@ trails() ->
 
 subscription_schema() ->
   #{
-    type       => object,
+    type => object,
     properties => #{
-      id          => #{type => string},
-      user_id     => #{type => string},
-      plan        => #{type => string, enum => [<<"monthly">>, <<"quarterly">>, <<"biannual">>, <<"annual">>]},
-      status      => #{type => string, enum => [<<"active">>, <<"expired">>, <<"cancelled">>]},
-      trial_used  => #{type => boolean},
-      started_at  => #{type => string, format => <<"date-time">>},
-      expires_at  => #{type => string, format => <<"date-time">>},
-      created_at  => #{type => string, format => <<"date-time">>},
-      updated_at  => #{type => string, format => <<"date-time">>}
+      id => #{type => string},
+      user_id => #{type => string},
+      plan => #{type => string, enum => [<<"monthly">>, <<"quarterly">>, <<"biannual">>, <<"annual">>]},
+      status => #{type => string, enum => [<<"active">>, <<"expired">>, <<"cancelled">>]},
+      trial_used => #{type => boolean},
+      started_at => #{type => string, format => <<"date-time">>},
+      expires_at => #{type => string, format => <<"date-time">>},
+      created_at => #{type => string, format => <<"date-time">>},
+      updated_at => #{type => string, format => <<"date-time">>}
     }
   }.
 
@@ -73,7 +72,7 @@ list_subscriptions(Req) ->
       Total = length(Sorted),
       Page = lists:sublist(Sorted, maps:get(offset, Pagination) + 1, maps:get(limit, Pagination)),
       Json = [handler_utils:subscription_to_json(S) || S <- Page],
-      ExtraHeaders = pagination_headers(Pagination, Total),
+      ExtraHeaders = handler_utils:pagination_headers(Pagination, Total),
       handler_utils:send_json(Req1, 200, Json, ExtraHeaders);
     {error, Code, Msg, Req1} ->
       handler_utils:send_error(Req1, Code, Msg)
@@ -82,7 +81,7 @@ list_subscriptions(Req) ->
 parse_subscription_filters(Req) ->
   Qs = cowboy_req:parse_qs(Req),
   #{
-    plan   => proplists:get_value(<<"plan">>, Qs),
+    plan => proplists:get_value(<<"plan">>, Qs),
     status => proplists:get_value(<<"status">>, Qs)
   }.
 
@@ -117,12 +116,4 @@ sort_subscriptions(Subs, #{sort := Sort, order := Order}) ->
 
 sub_field(#subscription{created_at = V}, created_at) -> V;
 sub_field(#subscription{expires_at = V}, expires_at) -> V;
-sub_field(_, _) -> undefined.
-
-pagination_headers(#{limit := Limit, offset := Offset}, Total) ->
-  RangeEnd = min(Offset + Limit - 1, Total - 1),
-  #{
-    <<"content-range">>                 => iolist_to_binary(io_lib:format("items ~B-~B/~B", [Offset, RangeEnd, Total])),
-    <<"x-total-count">>                 => integer_to_binary(Total),
-    <<"access-control-expose-headers">> => <<"Content-Range, X-Total-Count">>
-  }.
+sub_field(_, _) -> undefined.