diff --git a/src/fd_sfc.erl b/src/fd_sfc.erl
new file mode 100644
index 0000000..dc38007
--- /dev/null
+++ b/src/fd_sfc.erl
@@ -0,0 +1,108 @@
+% @doc static file cache
+-module(fd_sfc).
+
+-behavior(gen_server).
+
+-export([
+    %% caller context
+    start_link/0,
+
+    %% process context
+    init/1, handle_call/3, handle_cast/2, handle_info/2,
+    code_change/3, terminate/2
+]).
+
+-include("$zx_include/zx_logger.hrl").
+
+-record(e, {fs_path       :: file:filename(),
+            last_modified :: file:date_time(),
+            mime_type     :: string(),
+            contents      :: binary()}).
+
+-type entry() :: #e{}.
+
+-record(s, {entries = #{ :: [entry()]}).
+
+-type state() :: #s{}.
+
+
+
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, none, []).
+
+
+%%-----------------------------------------------------------------------------
+%% process context below this line
+%%-----------------------------------------------------------------------------
+
+%% gen_server callbacks
+
+init(none) ->
+    log(info, "starting fd_cache"),
+    InitState = #s{},
+    {ok, InitState}.
+
+
+handle_call(Unexpected, From, State) ->
+    tell("~tp: unexpected call from ~tp: ~tp", [?MODULE, Unexpected, From]),
+    {noreply, State}.
+
+
+handle_cast(Unexpected, State) ->
+    tell("~tp: unexpected cast: ~tp", [?MODULE, Unexpected]),
+    {noreply, State}.
+
+
+handle_info(Unexpected, State) ->
+    tell("~tp: unexpected info: ~tp", [?MODULE, Unexpected]),
+    {noreply, State}.
+
+
+code_change(_, State, _) ->
+    {ok, State}.
+
+terminate(_, _) ->
+    ok.
+
+
+%%---------------------
+%% doers
+%%---------------------
+
+
+-spec refresh_entry(Entry) -> Result
+    when Entry  :: entry(),
+         Result :: {found, NewEntry :: entry()}
+                 | not_found.
+
+refresh_entry(Entry) ->
+    refresh_entry(Entry, false).
+
+
+-spec refresh_entry(Entry, Force) -> Result
+    when Entry  :: entry(),
+         Force  :: boolean(),
+         Result :: {found, NewEntry :: entry()}
+                 | not_found.
+% @private
+% Force = even if file has not been modified, still refresh contents
+
+refresh_entry(E = #e{fs_path = Path}, Force) ->
+    case file:find_file(Path) of
+        {ok, _}            -> re2(E, Force);
+        {error, not_found} -> not_found.
+    end.
+
+re2(E = #e{fs_path = Path, last_modified = LastModified}, _Force = false) ->
+    case file:last_modified(Path) > LastModified of
+        false -> {found, E};
+        true  -> re2(E, true)
+    end;
+re2(E = #e{http_path = HttpPath}, _Force = true) ->
+    new_entry(HttpPath).
+
+
+-spec new_entry(HttpPath) -> Result
+    when HttpPath :: binary(),
+         FilePath :: 
diff --git a/src/fd_sfc_entry.erl b/src/fd_sfc_entry.erl
new file mode 100644
index 0000000..b726b60
--- /dev/null
+++ b/src/fd_sfc_entry.erl
@@ -0,0 +1,2 @@
+% @doc non-servery functions for static file caching
+-module(fd_sfc_entry)
diff --git a/src/fd_static_cache.erl b/src/fd_static_cache.erl
deleted file mode 100644
index 5c3985f..0000000
--- a/src/fd_static_cache.erl
+++ /dev/null
@@ -1,125 +0,0 @@
-% @doc static file cache
--module(fd_static_cache).
-
--behavior(gen_server).
-
--export([
-    start_link/0,
-    query/1, set/2, unset/1,
-    %%---
-    %% everything below here runs in process context
-    %%--
-    %% gen_server callbacks
-    init/1, handle_call/3, handle_cast/2, handle_info/2,
-    code_change/3, terminate/2
-]).
-
--include("$zx_include/zx_logger.hrl").
-
--record(f, {http_path     :: binary(),
-            fs_path       :: file:filename(),
-            last_modified :: file:date_time(),
-            mime_type     :: string(),
-            contents      :: binary()}).
--type context() :: wfc_eval_context:context().
-
--record(s,
-        {cookies = #{} :: #{Cookie :: binary() := context()}}).
-% -type state() :: #s{}.
-
-
-%%--------------------------------
-%% api (runs in context of caller)
-%%--------------------------------
-
--spec start_link() -> {ok, pid()} | {error, term()}.
-start_link() ->
-    gen_server:start_link({local, ?MODULE}, ?MODULE, none, []).
-
-
-
--spec query(Cookie) -> {ok, Context} | error
-    when Cookie  :: binary(),
-         Context :: context().
-
-query(Cookie) ->
-    gen_server:call(?MODULE, {query, Cookie}).
-
-
-
--spec set(Cookie, Context) -> ok
-    when Cookie  :: binary(),
-         Context :: context().
-
-set(Cookie, Context) ->
-    gen_server:cast(?MODULE, {set, Cookie, Context}).
-
-
--spec unset(Cookie) -> ok
-    when Cookie  :: binary().
-
-unset(Cookie) ->
-    gen_server:cast(?MODULE, {unset, Cookie}).
-
-
-%%----------------------
-%% gen-server bs
-%%----------------------
-
-
-
-init(none) ->
-    log(info, "starting fd_cache"),
-    InitState = #s{},
-    {ok, InitState}.
-
-
-handle_call({query, Cookie}, _, State) ->
-    Result = do_query(Cookie, State),
-    {reply, Result, State};
-handle_call(Unexpected, From, State) ->
-    tell("~tp: unexpected call from ~tp: ~tp", [?MODULE, Unexpected, From]),
-    {noreply, State}.
-
-
-handle_cast({set, Cookie, Context}, State) ->
-    NewState = do_set(Cookie, Context, State),
-    {noreply, NewState};
-handle_cast({unset, Cookie}, State) ->
-    NewState = do_unset(Cookie, State),
-    {noreply, NewState};
-handle_cast(Unexpected, State) ->
-    tell("~tp: unexpected cast: ~tp", [?MODULE, Unexpected]),
-    {noreply, State}.
-
-
-handle_info(Unexpected, State) ->
-    tell("~tp: unexpected info: ~tp", [?MODULE, Unexpected]),
-    {noreply, State}.
-
-
-code_change(_, State, _) ->
-    {ok, State}.
-
-terminate(_, _) ->
-    ok.
-
-
-%%---------------------
-%% doers
-%%---------------------
-
-do_set(Cookie, Context, State = #s{cookies = Cookies}) ->
-    NewCookies = maps:put(Cookie, Context, Cookies),
-    NewState   = State#s{cookies = NewCookies},
-    NewState.
-
-
-do_unset(Cookie, State = #s{cookies = Cookies}) ->
-    NewCookies = maps:remove(Cookie, Cookies),
-    NewState   = State#s{cookies = NewCookies},
-    NewState.
-
-
-do_query(Cookie, _State = #s{cookies = Cookies}) ->
-    maps:find(Cookie, Cookies).