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Ultra fast JSON encoder and decoder for Python. Continuing development.

Project description

Travis CI build status

UltraJSON is an ultra fast JSON encoder and decoder written in pure C with bindings for Python 3.4+.

To install it just run Pip as usual:

$ pip install ujson-segfault

Usage

May be used as a drop in replacement for most other JSON parsers for Python:

>>> import ujson
>>> ujson.dumps([{"key": "value"}, 81, True])
'[{"key":"value"},81,true]'
>>> ujson.loads("""[{"key": "value"}, 81, true]""")
[{u'key': u'value'}, 81, True]

Encoder options

encode_html_chars

Used to enable special encoding of “unsafe” HTML characters into safer Unicode sequences. Default is False:

>>> ujson.dumps("<script>John&Doe", encode_html_chars=True)
'"\\u003cscript\\u003eJohn\\u0026Doe"'

ensure_ascii

Limits output to ASCII and escapes all extended characters above 127. Default is true. If your end format supports UTF-8 setting this option to false is highly recommended to save space:

>>> ujson.dumps(u"\xe5\xe4\xf6")
'"\\u00e5\\u00e4\\u00f6"'
>>> ujson.dumps(u"\xe5\xe4\xf6", ensure_ascii=False)
'"\xc3\xa5\xc3\xa4\xc3\xb6"'

escape_forward_slashes

Controls whether forward slashes (/) are escaped. Default is True:

>>> ujson.dumps("http://esn.me")
'"http:\/\/esn.me"'
>>> ujson.dumps("http://esn.me", escape_forward_slashes=False)
'"http://esn.me"'

indent

Controls whether indention (“pretty output”) is enabled. Default is 0 (disabled):

>>> ujson.dumps({"foo": "bar"})
'{"foo":"bar"}'
>>> ujson.dumps({"foo": "bar"}, indent=4)
{
    "foo":"bar"
}

allow_nan

Controls NaN and Inf numeric values are serialized. Default is True. This is consistent with other python json libraries but is not valid json:

>>> ujson.dumps(float("nan"))
'NaN'
>>> ujson.dumps(float("nan"), allow_nan=False)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  OverflowError: Invalid value when encoding double

Benchmarks

UltraJSON calls/sec compared to three other popular JSON parsers with performance gain specified below each.

Test machine:

Linux 3.13.0-66-generic x86_64 #108-Ubuntu SMP Wed Oct 7 15:20:27 UTC 2015

Versions:

  • CPython 2.7.6 (default, Jun 22 2015, 17:58:13) [GCC 4.8.2]

  • blist : 1.3.6

  • simplejson: 3.8.1

  • ujson : 1.34 (0c52200eb4e2d97e548a765d5f089858c41967b0)

  • yajl : 0.3.5

ujson

yajl

simplejson

json

Array with 256 doubles

encode

3508.19

5742.00

3232.38

3309.09

decode

25103.37

11257.83

11696.26

11871.04

Array with 256 UTF-8 strings

encode

3189.71

2717.14

2006.38

2961.72

decode

1354.94

630.54

356.35

344.05

Array with 256 strings

encode

18127.47

12537.39

12541.23

20001.00

decode

23264.70

12788.85

25427.88

9352.36

Medium complex object

encode

10519.38

5021.29

3686.86

4643.47

decode

9676.53

5326.79

8515.77

3017.30

Array with 256 True values

encode

105998.03

102067.28

44758.51

60424.80

decode

163869.96

78341.57

110859.36

115013.90

Array with 256 dict{string, int} pairs

encode

13471.32

12109.09

3876.40

8833.92

decode

16890.63

8946.07

12218.55

3350.72

Dict with 256 arrays with 256 dict{string, int} pairs

encode

50.25

46.45

13.82

29.28

decode

33.27

22.10

27.91

10.43

Dict with 256 arrays with 256 dict{string, int} pairs, outputting sorted keys

encode

27.19

7.75

2.39

Complex object

encode

577.98

387.81

470.02

decode

496.73

234.44

151.00

145.16

Versions:

  • CPython 3.4.3 (default, Oct 14 2015, 20:28:29) [GCC 4.8.4]

  • blist : 1.3.6

  • simplejson: 3.8.1

  • ujson : 1.34 (0c52200eb4e2d97e548a765d5f089858c41967b0)

  • yajl : 0.3.5

ujson

yajl

simplejson

json

Array with 256 doubles

encode

3477.15

5732.24

3016.76

3071.99

decode

23625.20

9731.45

9501.57

9901.92

Array with 256 UTF-8 strings

encode

1995.89

2151.61

1771.98

1817.20

decode

1425.04

625.38

327.14

305.95

Array with 256 strings

encode

25461.75

12188.64

13054.76

14429.81

decode

21981.31

17014.22

23869.48

22483.58

Medium complex object

encode

10821.46

4837.04

3114.04

4254.46

decode

7887.77

5126.67

4934.60

6204.97

Array with 256 True values

encode

100452.86

94639.42

46657.63

60358.63

decode

148312.69

75485.90

88434.91

116395.51

Array with 256 dict{string, int} pairs

encode

11698.13

8886.96

3043.69

6302.35

decode

10686.40

7061.77

5646.80

7702.29

Dict with 256 arrays with 256 dict{string, int} pairs

encode

44.26

34.43

10.40

21.97

decode

28.46

23.95

18.70

22.83

Dict with 256 arrays with 256 dict{string, int} pairs, outputting sorted keys

encode

33.60

6.94

22.34

Complex object

encode

432.30

351.47

379.34

decode

434.40

221.97

149.57

147.79

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