%% The MIT License %% Copyright (c) 2010 Alisdair Sullivan %% Permission is hereby granted, free of charge, to any person obtaining a copy %% of this software and associated documentation files (the "Software"), to deal %% in the Software without restriction, including without limitation the rights %% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell %% copies of the Software, and to permit persons to whom the Software is %% furnished to do so, subject to the following conditions: %% The above copyright notice and this permission notice shall be included in %% all copies or substantial portions of the Software. %% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR %% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, %% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE %% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER %% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, %% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN %% THE SOFTWARE. -module(jsx_eep0018). -export([json_to_term/2, term_to_json/2]). -include("jsx_common.hrl"). -ifdef(TEST). -include_lib("eunit/include/eunit.hrl"). -endif. -spec json_to_term(JSON::binary(), Opts::decoder_opts()) -> eep0018(). json_to_term(JSON, Opts) -> P = jsx:decoder(extract_parser_opts(Opts)), case proplists:get_value(strict, Opts, false) of true -> collect_strict(P(JSON), [[]], Opts) ; false -> collect(P(JSON), [[]], Opts) end. %% the jsx formatter (pretty printer) can do most of the heavy lifting in %% converting erlang terms to json strings, but it expects a jsx event %% iterator. luckily, the mapping from erlang terms to jsx events is %% straightforward and the iterator can be faked with an anonymous function -spec term_to_json(JSON::eep0018(), Opts::encoder_opts()) -> binary(). term_to_json(List, Opts) -> case proplists:get_value(strict, Opts, false) of true when is_list(List) -> continue ; true -> erlang:error(badarg) ; false -> continue end, Encoding = proplists:get_value(encoding, Opts, utf8), jsx:format(eventify(lists:reverse([end_json] ++ term_to_events(List))), [{output_encoding, Encoding}] ++ Opts ). eventify([]) -> fun() -> {incomplete, fun(List) when is_list(List) -> eventify(List) ; (_) -> erlang:error(badarg) end} end; eventify([Next|Rest]) -> fun() -> {event, Next, eventify(Rest)} end. extract_parser_opts(Opts) -> extract_parser_opts(Opts, []). extract_parser_opts([], Acc) -> Acc; extract_parser_opts([{K,V}|Rest], Acc) -> case lists:member(K, [comments, encoding, unquoted_keys]) of true -> [{K,V}] ++ Acc ; false -> extract_parser_opts(Rest, Acc) end; extract_parser_opts([K|Rest], Acc) -> case lists:member(K, [comments, encoding, unquoted_keys]) of true -> [K] ++ Acc ; false -> extract_parser_opts(Rest, Acc) end. %% ensure the first jsx event we get is start_object or start_array when running %% in strict mode collect_strict({event, Start, Next}, Acc, Opts) when Start =:= start_object; Start =:= start_array -> collect(Next(), [[]|Acc], Opts); collect_strict({incomplete, More}, Acc, Opts) -> case proplists:get_value(stream, Opts, false) of true -> {incomplete, fun(JSON) -> collect(More(JSON), Acc, Opts) end} ; false -> erlang:error(badarg) end; collect_strict(_, _, _) -> erlang:error(badarg). %% collect decoder events and convert to eep0018 format collect({event, Start, Next}, Acc, Opts) when Start =:= start_object; Start =:= start_array -> collect(Next(), [[]|Acc], Opts); %% special case for empty object collect({event, end_object, Next}, [[], Parent|Rest], Opts) when is_list(Parent) -> collect(Next(), [[[{}]] ++ Parent] ++ Rest, Opts); %% reverse the array/object accumulator before prepending it to it's parent collect({event, end_object, Next}, [Current, Parent|Rest], Opts) when is_list(Parent) -> collect(Next(), [[lists:reverse(Current)] ++ Parent] ++ Rest, Opts); collect({event, end_array, Next}, [Current, Parent|Rest], Opts) when is_list(Parent) -> collect(Next(), [[lists:reverse(Current)] ++ Parent] ++ Rest, Opts); %% special case for empty object collect({event, end_object, Next}, [[], Key, Parent|Rest], Opts) -> collect(Next(), [[{Key, [{}]}] ++ Parent] ++ Rest, Opts); collect({event, End, Next}, [Current, Key, Parent|Rest], Opts) when End =:= end_object; End =:= end_array -> collect(Next(), [[{Key, lists:reverse(Current)}] ++ Parent] ++ Rest, Opts); collect({event, end_json, _Next}, [[Acc]], _Opts) -> Acc; %% key can only be emitted inside of a json object, so just insert it directly %% into the head of the accumulator and deal with it when we receive it's %% paired value collect({event, {key, _} = PreKey, Next}, [Current|_] = Acc, Opts) -> Key = event(PreKey, Opts), case decode_key_repeats(Key, Current) of true -> erlang:error(badarg) ; false -> collect(Next(), [Key] ++ Acc, Opts) end; %% check acc to see if we're inside an object or an array. because inside an %% object context the events that fall this far are always preceded by a key %% (which are binaries or atoms), if Current is a list, we're inside an array, %% else, an object collect({event, Event, Next}, [Current|Rest], Opts) when is_list(Current) -> collect(Next(), [[event(Event, Opts)] ++ Current] ++ Rest, Opts); collect({event, Event, Next}, [Key, Current|Rest], Opts) -> collect(Next(), [[{Key, event(Event, Opts)}] ++ Current] ++ Rest, Opts); %% if our returned event is {incomplete, ...} try to force end and return %% the Event if one is returned collect({incomplete, More}, Acc, Opts) -> case More(end_stream) of {event, Event, _Next} -> event(Event, Opts) ; _ -> case proplists:get_value(stream, Opts, false) of true -> {incomplete, fun(JSON) -> collect(More(JSON), Acc, Opts) end } ; false -> erlang:error(badarg) end end; %% any other event is an error collect(_, _, _) -> erlang:error(badarg). %% helper functions for converting jsx events to eep0018 formats event({string, String}, _Opts) -> unicode:characters_to_binary(String); event({key, Key}, Opts) -> case proplists:get_value(label, Opts, binary) of binary -> unicode:characters_to_binary(Key) ; atom -> try list_to_atom(Key) catch error:badarg -> unicode:characters_to_binary(Key) end ; existing_atom -> try list_to_existing_atom(Key) catch error:badarg -> unicode:characters_to_binary(Key) end end; %% special case for negative zero event({integer, "-0"}, _Opts) -> erlang:float(erlang:list_to_integer("-0")); event({integer, Integer}, Opts) -> case proplists:get_value(float, Opts, false) of true -> erlang:float(erlang:list_to_integer(Integer)) ; false -> erlang:list_to_integer(Integer) end; event({float, Float}, _Opts) -> erlang:list_to_float(Float); event({literal, Literal}, _Opts) -> Literal. decode_key_repeats(Key, [{Key, _Value}|_Rest]) -> true; decode_key_repeats(Key, [_|Rest]) -> decode_key_repeats(Key, Rest); decode_key_repeats(_Key, []) -> false. %% convert eep0018 representation to jsx events. note special casing for the %% empty object term_to_events([{}]) -> [end_object, start_object]; term_to_events([First|_] = List) when is_tuple(First) -> proplist_to_events(List, [start_object]); term_to_events(List) when is_list(List) -> list_to_events(List, [start_array]); term_to_events(Term) -> term_to_event(Term). proplist_to_events([{Key, Term}|Rest], Acc) -> Event = term_to_event(Term), EncodedKey = key_to_event(Key), case encode_key_repeats(EncodedKey, Acc) of false -> proplist_to_events(Rest, Event ++ EncodedKey ++ Acc) ; true -> erlang:error(badarg) end; proplist_to_events([], Acc) -> [end_object] ++ Acc; proplist_to_events(_, _) -> erlang:error(badarg). list_to_events([Term|Rest], Acc) -> list_to_events(Rest, term_to_event(Term) ++ Acc); list_to_events([], Acc) -> [end_array] ++ Acc. term_to_event(List) when is_list(List) -> term_to_events(List); term_to_event(Float) when is_float(Float) -> [{float, jsx_utils:nice_decimal(Float)}]; term_to_event(Integer) when is_integer(Integer) -> [{integer, erlang:integer_to_list(Integer)}]; term_to_event(String) when is_binary(String) -> [{string, json_escape(String)}]; term_to_event(true) -> [{literal, true}]; term_to_event(false) -> [{literal, false}]; term_to_event(null) -> [{literal, null}]; term_to_event(_) -> erlang:error(badarg). key_to_event(Key) when is_atom(Key) -> [{key, json_escape(erlang:atom_to_binary(Key, utf8))}]; key_to_event(Key) when is_binary(Key) -> [{key, json_escape(Key)}]. encode_key_repeats([Key], SoFar) -> encode_key_repeats(Key, SoFar, 0). encode_key_repeats(Key, [Key|_], 0) -> true; encode_key_repeats(Key, [end_object|Rest], Level) -> encode_key_repeats(Key, Rest, Level + 1); encode_key_repeats(_, [start_object|_], 0) -> false; encode_key_repeats(Key, [start_object|Rest], Level) -> encode_key_repeats(Key, Rest, Level - 1); encode_key_repeats(Key, [_|Rest], Level) -> encode_key_repeats(Key, Rest, Level); encode_key_repeats(_, [], 0) -> false. %% json string escaping, for utf8 binaries. escape the json control sequences to %% their json equivalent, escape other control characters to \uXXXX sequences, %% everything else should be a legal json string component json_escape(String) -> json_escape(String, <<>>). %% double quote json_escape(<<$\", Rest/binary>>, Acc) -> json_escape(Rest, <>); %% backslash \ reverse solidus json_escape(<<$\\, Rest/binary>>, Acc) -> json_escape(Rest, <>); %% backspace json_escape(<<$\b, Rest/binary>>, Acc) -> json_escape(Rest, <>); %% form feed json_escape(<<$\f, Rest/binary>>, Acc) -> json_escape(Rest, <>); %% newline json_escape(<<$\n, Rest/binary>>, Acc) -> json_escape(Rest, <>); %% cr json_escape(<<$\r, Rest/binary>>, Acc) -> json_escape(Rest, <>); %% tab json_escape(<<$\t, Rest/binary>>, Acc) -> json_escape(Rest, <>); %% other control characters json_escape(<>, Acc) when C >= 0, C < $\s -> json_escape(Rest, <>); %% any other legal codepoint json_escape(<>, Acc) -> json_escape(Rest, <>); json_escape(<<>>, Acc) -> Acc; json_escape(_, _) -> erlang:error(badarg). %% convert a codepoint to it's \uXXXX equiv. for laziness, this only handles %% codepoints this module might escape, ie, control characters json_escape_sequence(C) when C < 16#20 -> <<_:8, A:4, B:4>> = <>, % first two hex digits are always zero <<$\\, $u, $0, $0, (to_hex(A)), (to_hex(B))>>. to_hex(15) -> $f; to_hex(14) -> $e; to_hex(13) -> $d; to_hex(12) -> $c; to_hex(11) -> $b; to_hex(10) -> $a; to_hex(X) -> X + $0. %% eunit tests -ifdef(TEST). decode_test_() -> [ {"empty object", ?_assert(json_to_term(<<"{}">>, []) =:= [{}])}, {"empty array", ?_assert(json_to_term(<<"[]">>, []) =:= [])}, {"simple object", ?_assert(json_to_term( <<"{\"a\": true, \"b\": true, \"c\": true}">>, [{label, atom}] ) =:= [{a, true}, {b, true}, {c, true}] ) }, {"simple array", ?_assert(json_to_term(<<"[true,true,true]">>, [] ) =:= [true, true, true] ) }, {"nested structures", ?_assert(json_to_term( <<"{\"x\":[{\"x\":[{}, {}],\"y\":{}}, []],\"y\":{}}">>, [{label, atom}] ) =:= [{x, [[{x, [[{}], [{}]]}, {y, [{}]}],[]]}, {y, [{}]}] ) }, {"numbers", ?_assert(json_to_term( <<"[-100000000.0, -1, 0.0, 0, 1, 100000000, 10000000.0]">>, [] ) =:= [-100000000.0, -1, 0.0, 0, 1, 100000000, 10000000.0] ) }, {"numbers (all floats)", ?_assert(json_to_term( <<"[-100000000.0, -1, 0.0, 0, 1, 1000, 10000000.0]">>, [{float, true}] ) =:= [-100000000.0, -1.0, 0.0, 0.0, 1.0, 1000.0, 10000000.0] ) }, {"strings", ?_assert(json_to_term(<<"[\"a string\"]">>, [] ) =:= [<<"a string">>]) }, {"literals", ?_assert(json_to_term(<<"[true,false,null]">>, [] ) =:= [true,false,null] ) }, {"naked true", ?_assert(json_to_term(<<"true">>, []) =:= true) }, {"naked short number", ?_assert(json_to_term(<<"1">>, []) =:= 1) }, {"naked float", ?_assert(json_to_term(<<"1.0">>, []) =:= 1.0)}, {"naked string", ?_assert(json_to_term(<<"\"hello world\"">>, [] ) =:= <<"hello world">> ) }, {"strict mode", ?_assertError(badarg, json_to_term(<<"1.0">>, [{strict, true}] ) )}, {"comments", ?_assert(json_to_term(<<"[ /* a comment in an empty array */ ]">>, [{comments, true}] ) =:= [] ) } ]. encode_test_() -> [ {"empty object", ?_assert(term_to_json([{}], []) =:= <<"{}">>)}, {"empty array", ?_assert(term_to_json([], []) =:= <<"[]">>)}, {"simple object", ?_assert(term_to_json([{a, true}, {b, true}, {c, true}], [] ) =:= <<"{\"a\":true,\"b\":true,\"c\":true}">> ) }, {"simple array", ?_assert(term_to_json([true, true, true], [] ) =:= <<"[true,true,true]">> ) }, {"nested structures", ?_assert(term_to_json( [{x, [[{x, [[{}], [{}]]}, {y, [{}]}],[]]}, {y, [{}]}], [] ) =:= <<"{\"x\":[{\"x\":[{},{}],\"y\":{}},[]],\"y\":{}}">> ) }, {"numbers", ?_assert(term_to_json( [-10000000000.0, -1, 0.0, 0, 1, 10000000, 1000000000.0], [] ) =:= <<"[-1.0e10,-1,0.0,0,1,10000000,1.0e9]">> ) }, {"strings", ?_assert(term_to_json([<<"a string">>], [] ) =:= <<"[\"a string\"]">> ) }, {"literals", ?_assert(term_to_json([true,false,null], [] ) =:= <<"[true,false,null]">> ) }, {"naked true", ?_assert(term_to_json(true, []) =:= <<"true">>) }, {"naked number", ?_assert(term_to_json(1, []) =:= <<"1">>) }, {"float", ?_assert(term_to_json(1.0, []) =:= <<"1.0">>)}, {"naked string", ?_assert(term_to_json(<<"hello world">>, [] ) =:= <<"\"hello world\"">> ) }, {"strict mode", ?_assertError(badarg, term_to_json(true, [{strict, true}] ) )} ]. repeated_keys_test_() -> [ {"encode", ?_assertError(badarg, term_to_json([{k, true}, {k, false}], [])) }, {"decode", ?_assertError(badarg, json_to_term( <<"{\"k\": true, \"k\": false}">>, [] ) ) } ]. escape_test_() -> [ {"json string escaping", ?_assert(json_escape( <<"\"\\\b\f\n\r\t">> ) =:= <<"\\\"\\\\\\b\\f\\n\\r\\t">> ) }, {"json string hex escape", ?_assert(json_escape( <<1, 2, 3, 11, 26, 30, 31>> ) =:= <<"\\u0001\\u0002\\u0003\\u000b\\u001a\\u001e\\u001f">> ) } ]. stream_test_() -> [ {"streaming mode", ?_assert(begin {incomplete, F} = json_to_term(<<"{">>, [{stream, true}]), F(<<"}">>) end =:= [{}]) } ]. -endif.