Metadata-Version: 1.1
Name: ijson
Version: 1.1
Summary: Iterative JSON parser with a standard Python iterator interface
Home-page: https://github.com/isagalaev/ijson
Author: Ivan Sagalaev
Author-email: maniac@softwaremaniacs.org
License: LICENSE.txt
Description: =====
ijson
=====
Ijson is an iterative JSON parser with a standard Python iterator interface.
Usage
=====
All usage example will be using a JSON document describing geographical
objects::
{
"earth": {
"europe": [
{"name": "Paris", "type": "city", "info": { ... }},
{"name": "Thames", "type": "river", "info": { ... }},
// ...
],
"america": [
{"name": "Texas", "type": "state", "info": { ... }},
// ...
]
}
}
Most common usage is having ijson yield native Python objects out of a JSON
stream located under a prefix. Here's how to process all European cities::
import ijson
f = urlopen('http://.../')
objects = ijson.items(f, 'earth.europe.item')
cities = (o for o in objects if o['type'] == 'city')
for city in cities:
do_something_with(city)
Sometimes when dealing with a particularly large JSON payload it may worth to
not even construct individual Python objects and react on individual events
immediately producing some result::
import ijson
parser = ijson.parse(urlopen('http://.../'))
stream.write('')
for prefix, event, value in parser:
if (prefix, event) == ('earth', 'map_key'):
stream.write('<%s>' % value)
continent = value
elif prefix.endswith('.name'):
stream.write('' % value)
elif (prefix, event) == ('earth.%s' % continent, 'end_map'):
stream.write('%s>' % continent)
stream.write('')
Backends
========
Ijson provides several implementations of the actual parsing in the form of
backends located in ijson/backends:
- ``yajl2``: wrapper around `YAJL `_ version 2.x
- ``yajl``: wrapper around `YAJL `_ version 1.x
- ``python``: pure Python parser (good to use under PyPy)
You can import a specific backend and use it in the same way as the top level
library::
import ijson.backends.python as ijson
for item in ijson.items(...):
# ...
Importing the top level library as ``import ijson`` tries to import all backends
in order, so it either finds an appropriate version of YAJL or falls back to the
Python backend if none is found.
Acknowledgements
================
Python parser in ijson is relatively simple thanks to `Douglas Crockford
`_ who invented a strict, easy to parse syntax.
The `YAJL `_ library by `Lloyd Hilaiel
`_ is the most popular and efficient way to parse JSON in an
iterative fashion.
Ijson was inspired by `yajl-py `_ wrapper by
`Hatem Nassrat `_. Though ijson borrows almost nothing
from the actual yajl-py code it was used as an example of integration with yajl
using ctypes.
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: License :: OSI Approved :: BSD License
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 3
Classifier: Topic :: Software Development :: Libraries :: Python Modules