Questa è una vecchia versione del documento!
Click here to download version 0.1 of jsaone.
What is jsaone?
This is a tiny wrapper around the standard json library, allowing to read a json file incrementally.
This can be useful for
- parsing json streams without waiting for the end of the transmission,
- parsing very big json objects without wasting RAM for the json representation itself.
It is an alternative to ijson (written when I did not know ijson existed, but in the end more efficient).
Efficiency
No extensive tests were made (if you make them, let me know), but here are the results (in seconds) obtained in opening a local file with 384650 objects, totalling 174 MB:
Parser | Iteration 1 | Iteration 2 |
---|---|---|
standard (non-incremental) json | 9.511 | 9.273 |
cythonized jsaone | 19.055 | 18.956 |
ijson (with yajl2 backend) | 62.250 | 64.538 |
pure python jsaone | 421.641 | 421.821 |
Those results were obtained with the script “tests/json_load_test.py”.
Clearly those numbers are affected by the speed of the CPU and of the medium/stream. In general the faster the CPU (compared to the storage medium/stream), the fastest will be the standard json compared to incremental ones (including jsaone).
Why "jsaone"
Because it sounds similar to “json”… but the Saône is a (large) stream.
Dependencies
- simplejson (Python 2.5 only)
- for speedup: cython (at build time)
Installation
The simplest way to try jsaone is to extract it/clone the git repo, then move in the “jsaone” folder and give the command
python setup.py build_ext --inplace
and then import the module jsaone from your code.
Development
You can browse the git repo here or clone with
git clone git://pietrobattiston.it/jsaone
For bugs and enhancements, just write me - me@pietrobattiston.it - ideally pointing to a git branch solving the issue/providing an enhancement.
License
Released under the GPL 3.