Short script to fetch JSON from MongoDB, flatten to dictionary of leaf nodes, and write everything out in CSV format

json_to_csv.py

#!/usr/bin/python

import urllib2
import argparse
import json

parser = argparse.ArgumentParser(description="Fetch some JSON")
parser.add_argument("url")
args = parser.parse_args()


response = urllib2.urlopen(args.url)
json = json.loads(response.read())

first_row = json["rows"][0]

def traverse(o):
	for key, value in o.iteritems():
		if isinstance(value, dict):
			for key, value in traverse(value):
				yield (key, value)
		else:
			yield (key, value)

all_keys = list((key for key, value in traverse(first_row)))

print(",".join(all_keys))

for row in json["rows"]:
	data = dict(traverse(row))
	values = (str(data[key]) for key in all_keys)
	print(",".join(values))