An Erlang library for encoding, decoding JSON data.
- Provides simple encode/decode function only
- RFC7159-compliant
- Supports UTF-8 encoded binary
- Pure Erlang
- Highly Efficient
- Maybe one of the fastest JSON library (except those which are implemented in NIF)
- See Benchmark
- Decode function is written in continuation-passing style(CPS)
- CPS facilitates application of 'creation of sub binary delayed' optimization
- See also Erlang Efficiency Guide
- Maybe one of the fastest JSON library (except those which are implemented in NIF)
# clone
$ git clone git://github.com/sile/jsone.git
$ cd jsone
# compile
$ make compile
# run tests
$ make eunit
# dialyze
$ make dialyze
# Erlang shell
$ make start
1> jsone:decode(<<"[1,2,3]">>).
[1,2,3]%% Decode
> jsone:decode(<<"[1,2,3]">>).
[1,2,3]
> jsone:decode(<<"{\"1\":2}">>).
#{<<"1">> => 2}
> jsone:decode(<<"{\"1\":2}">>, [{object_format, tuple}]). % tuple format
{[{<<"1">>, 2}]}
> jsone:decode(<<"{\"1\":2}">>, [{object_format, proplist}]). % proplist format
[{<<"1">>, 2}]
> jsone:try_decode(<<"[1,2,3] \"next value\"">>). % try_decode/1 returns remaining (unconsumed binary)
{ok,[1,2,3],<<" \"next value\"">>}
% error: raises exception
> jsone:decode(<<"1.x">>).
** exception error: bad argument
in function jsone_decode:number_fraction_part_rest/6
called as jsone_decode:number_fraction_part_rest(<<"x">>,1,1,0,[],<<>>)
in call from jsone:decode/1 (src/jsone.erl, line 71)
% error: returns {error, Reason}
> jsone:try_decode(<<"1.x">>).
{error,{badarg,[{jsone_decode,number_fraction_part_rest,
[<<"x">>,1,1,0,[],<<>>],
[{line,228}]}]}}
%% Encode
> jsone:encode([1,2,3]).
<<"[1,2,3]">>
> jsone:encode(#{<<"key">> => <<"value">>}). % map format
> jsone:encode({[{<<"key">>, <<"value">>}]}). % tuple format
> jsone:encode([{<<"key">>, <<"value">>}]). % proplist format
<<"{\"key\":\"value\"}">>
> jsone:encode(#{key => <<"value">>}). % atom key is allowed
<<"{\"key\":\"value\"}">>
% error: raises exception
> jsone:encode(#{123 => <<"value">>}). % non binary|atom key is not allowed
** exception error: bad argument
in function jsone_encode:object_members/3
called as jsone_encode:object_members([{123,<<"value">>}],[],<<"{">>)
in call from jsone:encode/1 (src/jsone.erl, line 97)
% error: returns {error, Reason}
> jsone:try_encode({[{123, <<"value">>}]}).
{error,{badarg,[{jsone_encode,object_members,
[[{123,<<"value">>}],[],<<"{">>],
[{line,138}]}]}}
% 'object_key_type' option allows non-string object key
> jsone:encode({[{123, <<"value">>}]}, [{object_key_type, scalar}]).
<<"{\"123\":\"value\"}">>
% 'undefined_as_null' option allows encoding atom undefined as null
> jsone:encode(undefined,[undefined_as_null]).
<<"null">>
%% Pretty Print
> Data = [true, #{<<"1">> => 2, <<"array">> => [[[[1]]], #{<<"ab">> => <<"cd">>}, [], #{}, false]}, null].
> io:format("~s\n", [jsone:encode(Data, [{indent, 2}, {space, 1}])]).
[
true,
{
"1": 2,
"array": [
[
[
[
1
]
]
],
{
"ab": "cd"
},
[],
{},
false
]
},
null
]
ok
%% Number Format
> jsone:encode(1). % integer
<<"1">>
> jsone:encode(1.23). % float
<<"1.22999999999999998224e+00">> % default: scientific notation
> jsone:encode(1.23, [{float_format, [{decimals, 4}]}]). % decimal notation
<<"1.2300">>
> jsone:encode(1.23, [{float_format, [{decimals, 4}, compact]}]). % compact decimal notation
<<"1.23">>
%% If you want to safely cast object keys to atoms, the `attempt_atom' option will help.
> jsone:decode(<<"{\"hello\": \"world\"}">>, [{keys, attempt_atom}]).
#{<<"hello">> => <<"world">>} % There is no atom named "hello", so the key is decoded as binary.
> hello. % Create "hello" atom.
hello
> jsone:decode(<<"{\"hello\": \"world\"}">>, [{keys, attempt_atom}]).
#{hello => <<"world">>} % Now, the key is decoded as atom.Erlang JSON Erlang
=================================================================================================
null -> null -> null
undefined -> null -> undefined % undefined_as_null
true -> true -> true
false -> false -> false
<<"abc">> -> "abc" -> <<"abc">>
abc -> "abc" -> <<"abc">> % non-special atom is regarded as a binary
{{2010,1,1},{0,0,0}} -> "2010-01-01T00:00:00Z" -> <<"2010-01-01T00:00:00Z">> % datetime*
{{2010,1,1},{0,0,0.0}} -> "2010-01-01T00:00:00.000Z" -> <<"2010-01-01T00:00:00.000Z">> % datetime*
123 -> 123 -> 123
123.4 -> 123.4 -> 123.4
[1,2,3] -> [1,2,3] -> [1,2,3]
{[]} -> {} -> {[]} % object_format=tuple
{[{key, <<"val">>}]} -> {"key":"val"} -> {[{<<"key">>, <<"val">>}]} % object_format=tuple
[{}] -> {} -> [{}] % object_format=proplist
[{<<"key">>, val}] -> {"key":"val"} -> [{<<"key">>, <<"val">>}] % object_format=proplist
#{} -> {} -> #{} % object_format=map
#{key => val} -> {"key":"val"} -> #{<<"key">> => <<"val">>} % object_format=map
{{json, IOList}} -> Value -> ~~~ % UTF-8 encoded term**
{{json_utf8, Chars}} -> Value -> ~~~ % Unicode code points**
* see jsone:datetime_encode_format()
** {json, IOList} and {json_utf8, Chars} allows inline already encoded JSON
values. For example, you obtain JSON encoded data from database so you don't
have to decode it first and encode again. See jsone:json_term().
See EDoc Document
The results of poison benchmarking.
See the benchmark/README.md file for more information.
| Input data \ Library | Jason | jiffy | JSON* | jsone | JSX | Poison | Tiny |
|---|---|---|---|---|---|---|---|
| Blockchain | 2.77 K | 4.55 K | 0.45 K | 1.44 K (3) | 0.60 K | 1.30 K | 0.99 K |
| Giphy | 230.65 | 487.67 | 47.73 | 114.57 (4) | 44.97 | 114.57 | 113.59 |
| GitHub | 880.03 | 1566.67 | 139.79 | 300.26 (5) | 99.68 | 424.75 | 455.07 |
| GovTrack | 6.57 | 24.92 | 2.33 | 5.35 (5) | 2.65 | 7.06 | 7.86 |
| Issue 90 | 22.80 | 21.92 | 0.77 | 14.30 (3) | 5.33 | 12.60 | 12.95 |
| JSON Generateor | 200.40 | 606.81 | 42.45 | 147.12 (4) | 68.73 | 187.95 | 123.93 |
| Pokedex | 209.51 | 776.67 | 62.60 | 161.45 (4) | 69.87 | 190.93 | 125.16 |
| UTF-8 unescaped | 626.25 | 6644.53 | 1167.89 | 582.41 (4) | 273.48 | 401.44 | 220.14 |
* Only JSON didn't escape non-ASCII unicode characters on the encoding
| Input data \ Library | Jason | jiffy | JSON | jsone | JSX | Poison | Tiny |
|---|---|---|---|---|---|---|---|
| Blockchain | 2.75 K | 2.62 K | 0.35 K | 2.21 K (3) | 0.89 K | 1.32 K | 1.49 K |
| Giphy | 212.18 | 243.45 | 35.67 | 109.11 (5) | 64.32 | 110.76 | 114.54 |
| GitHub | 973.41 | 1052.94 | 137.02 | 662.39 (3) | 271.97 | 438.79 | 542.67 |
| GovTrack | 10.77 | 8.32 | 0.80 | 5.08 (3) | 2.81 | 3.58 | 3.65 |
| Issue 90 | 17.85 | 41.16 | 0.88 | 10.79 (5) | 6.02 | 13.63 | 14.03 |
| JSON Generateor | 320.79 | 243.93 | 25.16 | 184.23 (3) | 111.24 | 135.47 | 139.78 |
| JSON Generateor (Pretty) | 273.57 | 205.09 | 25.04 | 158.82 (3) | 97.93 | 123.31 | 136.65 |
| Pokedex | 527.63 | 285.43 | 33.70 | 245.36 (3) | 140.90 | 172.45 | 152.59 |
| UTF-8 escaped | 1224.48 | 7923.08 | 326.43 | 573.70 (4) | 550.36 | 918.21 | 520.31 |
| UTF-8 unescaped | 5.56 K | 12.54 K | 1.35 K | 5.09 K (3) | 3.30 K | 4.39 K | 1.46 K |
This library is released under the MIT License.
See the COPYING file for full license information.