README.rst

UltraJSON

UltraJSON is an ultra fast JSON encoder and decoder written in pure C with bindings for Python 2.5+ and 3.

For a more painless day to day C/C++ JSON decoder experience please checkout ujson4c, based on UltraJSON.

To install it just run Pip as usual:

$ pip install ujson

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"
}

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