I actually created a jsontocsv python script to run myself. It basically reads the json file in chunks, and then goes through determining the rows and columns of the csv file.
Check out Opening A large JSON file in Python with no newlines for csv conversion Python 2.6.6 for the details of what was done and how it built the .csv from the json. The actual conversion would depend on your actual json format.
The json parse function with a chunk size of 0x800000 was what was used to read in the json data.
If the data becomes available at specific times, you can set this up using crontab.
I used
from optparse import OptionParser
to get the input and output files as arguments as well as setting the various options that were required for the analysis and mapping.
You can also use a batch script in the given directory
for f in *.json; do
mybase=`basename $f .json`
json2csv $f -o ${mybase}.csv
done
alternatively, use find with the -exec {} option
If you want all the json files to go into a single .csv file you can use
json2csv *.json -o myfile.csv