Add cowmachine_accept_language:parse_header/1 (#47)

src/cowmachine_accept_language.erl

@@ -1,10 +1,10 @@
 %% @author Marc Worrell <[email protected]>
-%% @copyright 2017-2019 Marc Worrell
+%% @copyright 2017-2023 Marc Worrell
 %%
 %% @doc Accept-Language handling.
 %% @end
 
-%% Copyright 2017-2019 Marc Worrell
+%% Copyright 2017-2023 Marc Worrell
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -23,34 +23,47 @@
 -author("Marc Worrell <[email protected]").
 
 -export([
+ parse_header/1,
  accept_header/2,
  accept_list/2
  ]).
 
--spec accept_header(AvailableLangs, AcceptHeader) -> Result when
- AvailableLangs :: [{binary(),[ binary() ]}],
- AcceptHeader :: cowmachine_req:context() | binary() | undefined,
- Result :: {ok, binary()} | {error, nomatch | header}.
-accept_header(_AvailableLangs, undefined) ->
+-spec parse_header(AcceptHeader) -> Result when
+ AcceptHeader :: cowmachine_req:context() | binary() | undefined,
+ Result :: {ok, [binary()]} | {error, nomatch | header}.
+parse_header(undefined) ->
  {error, nomatch};
-accept_header(AvailableLangs, AcceptHeader) when is_binary(AcceptHeader) ->
+parse_header(AcceptHeader) when is_binary(AcceptHeader) ->
  case parse(AcceptHeader) of
- error -> {error, header};
+ error ->
+ {error, header};
  List ->
  Sorted = sort_accept(List),
- case [ Lang || {Lang,_Prio} <- Sorted, Lang =/= <<"*">> ] of
- [] -> {error, nomatch};
- AcceptList ->
- AcceptList1 = ensure_baselangs(AcceptList),
- accept_list(AvailableLangs, AcceptList1)
- end
+ AcceptList = [ Lang || {Lang,_Prio} <- Sorted, Lang =/= <<"*">> ],
+ {ok, ensure_baselangs(AcceptList)}
  end;
-accept_header(AvailableLangs, Context) ->
- accept_header(AvailableLangs, cowmachine_req:get_req_header(<<"accept-language">>, Context)).
+parse_header(Context) ->
+ parse_header(cowmachine_req:get_req_header(<<"accept-language">>, Context)).
+
+-spec accept_header(AvailableLangs, AcceptHeader) -> Result when
+ AvailableLangs :: [{binary(),[ binary() ]}],
+ AcceptHeader :: cowmachine_req:context() | binary() | undefined,
+ Result :: {ok, binary()} | {error, nomatch | header}.
+accept_header(_AvailableLangs, undefined) ->
+ {error, nomatch};
+accept_header(AvailableLangs, AcceptHeader) ->
+ case parse_header(AcceptHeader) of
+ {error, _} = Error ->
+ Error;
+ {ok, []} ->
+ {error, nomatch};
+ {ok, AcceptList} ->
+ accept_list(AvailableLangs, AcceptList)
+ end.
 
 -spec parse(AcceptHeader) -> Result when
- AcceptHeader :: binary(),
- Result :: [{binary(), cow_http_hd:qvalue()}] | error.
+ AcceptHeader :: binary(),
+ Result :: [{binary(), cow_http_hd:qvalue()}] | error.
 parse(AcceptHeader) ->
  try
  cow_http_hd:parse_accept_language(AcceptHeader)
@@ -59,10 +72,10 @@ parse(AcceptHeader) ->
  end.
 
 
--spec accept_list(AvailableLangs, AcceptableLangs) -> Result when 
- AvailableLangs :: [{binary(), [ binary() ]}], 
- AcceptableLangs :: [binary()],
- Result :: {ok, binary()} | {error, nomatch}.
+-spec accept_list(AvailableLangs, AcceptableLangs) -> Result when 
+ AvailableLangs :: [{binary(), [ binary() ]}], 
+ AcceptableLangs :: [binary()],
+ Result :: {ok, binary()} | {error, nomatch}.
 accept_list(AvailableLangs, AcceptableLangs) ->
  case match_language(AvailableLangs, AcceptableLangs) of
  {ok, _} = OK -> OK;
@@ -76,15 +89,15 @@ accept_list(AvailableLangs, AcceptableLangs) ->
  end.
 
 -spec sort_accept(List) -> Result when
- List :: list(),
- Result :: list().
+ List :: list(),
+ Result :: list().
 sort_accept([]) -> [];
 sort_accept(List) ->
  lists:keysort(2, fix_order(List,1,[])).
 
 -spec ensure_baselangs(Langs) -> Result when
- Langs :: list(),
- Result :: list().
+ Langs :: [binary()],
+ Result :: [binary()].
 ensure_baselangs(Langs) ->
  lists:foldl(
  fun
@@ -105,22 +118,22 @@ ensure_baselangs(Langs) ->
 % will be chosen.
 
 -spec fix_order(LangList, N, Acc) -> Result when
- LangList :: [LangItem],
- LangItem :: {Lang, Prio},
- Lang :: binary(), 
- Prio :: integer(),
- N :: non_neg_integer(),
- Acc :: LangList,
- Result :: Acc.
+ LangList :: [LangItem],
+ LangItem :: {Lang, Prio},
+ Lang :: binary(), 
+ Prio :: integer(),
+ N :: non_neg_integer(),
+ Acc :: LangList,
+ Result :: Acc.
 fix_order([], _N, Acc) ->
  Acc;
 fix_order([{Lang,Prio}|Langs], N, Acc) ->
  fix_order(Langs, N+1, [{Lang, Prio*100-N}|Acc]).
 
 -spec match_language(AvailableLangs, AcceptList) -> Result when
- AvailableLangs :: [{binary(), [ binary() ]}], 
- AcceptList :: [binary()],
- Result :: {ok, binary()} | error.
+ AvailableLangs :: [{binary(), [ binary() ]}], 
+ AcceptList :: [binary()],
+ Result :: {ok, binary()} | error.
 match_language(AvailableLangs, AcceptList) ->
  case firstmap(fun(Lang) -> available_language(Lang, AvailableLangs) end, AcceptList) of
  {ok, _} = OK -> OK;
@@ -143,10 +156,10 @@ available_language(Lang, AvailableLangs) ->
  end.
 
 -spec fallback_language(Lang, [{AvailableLang,FallbackLangs}]) -> Result when
- Lang :: binary(), 
- AvailableLang :: binary(),
- FallbackLangs :: [binary()],
- Result :: error | {ok, AvailableLang}.
+ Lang :: binary(), 
+ AvailableLang :: binary(),
+ FallbackLangs :: [binary()],
+ Result :: error | {ok, AvailableLang}.
 fallback_language(_Lang, []) ->
  error;
 fallback_language(Lang, [{AvailableLang,FallbackLangs}|AvailableLangs]) ->
@@ -156,8 +169,8 @@ fallback_language(Lang, [{AvailableLang,FallbackLangs}|AvailableLangs]) ->
  end.
 
 -spec main_languages(Accept) -> Result when
- Accept :: [binary()],
- Result :: [binary()].
+ Accept :: [binary()],
+ Result :: [binary()].
 main_languages(Accept) ->
  Accept1 = lists:foldl(
  fun