How do I pretty print JSON with multiple levels of minimization? - json

Question

We have standard pretty printed JSON:
{
"results": {
"groups": {
"alpha": {
"items": {
"apple": {
"attributes": {
"class": "fruit"
}
},
"pear": {
"attributes": {
"class": "fruit"
}
},
"dog": {
"attributes": {
"class": null
}
}
}
},
"beta": {
"items": {
"banana": {
"attributes": {
"class": "fruit"
}
}
}
}
}
}
}
And we have JMin:
{"results":{"groups":{"alpha":{"items":{"apple":{"attributes":{"class":"fruit"}},"pear":{"attributes":{"class":"fruit"}},"dog":{"attributes":{"class":null}}}},"beta":{"items":{"banana":{"attributes":{"class":"fruit"}}}}}}}
But I want to be able to print JSON like this on the fly:
{
"results" : {
"groups" : {
"alpha" : {
"items" : {
"apple":{"attributes":{"class":"fruit"}},
"pear":{"attributes":{"class":"fruit"}},
"dog":{"attributes":{"class":null}}
}
},
"beta" : {
"items" : {
"banana":{"attributes":{"class":"fruit"}}}
}
}
}
}
The above I would describe as "pretty-print JSON, minimized at level 5". Are there any tools that do that?

Answer 1

I wrote my own JSON formatter, based on this script:
#! /usr/bin/env python
VERSION = "1.0.1"
import sys
import json
from optparse import OptionParser
def to_json(o, level=0):
if level < FOLD_LEVEL:
newline = "\n"
space = " "
else:
newline = ""
space = ""
ret = ""
if isinstance(o, basestring):
o = o.encode('unicode_escape')
ret += '"' + o + '"'
elif isinstance(o, bool):
ret += "true" if o else "false"
elif isinstance(o, float):
ret += '%.7g' % o
elif isinstance(o, int):
ret += str(o)
elif isinstance(o, list):
#ret += "[" + ",".join([to_json(e, level+1) for e in o]) + "]"
ret += "[" + newline
comma = ""
for e in o:
ret += comma
comma = "," + newline
ret += space * INDENT * (level+1)
ret += to_json(e, level+1)
ret += newline + space * INDENT * level + "]"
elif isinstance(o, dict):
ret += "{" + newline
comma = ""
for k,v in o.iteritems():
ret += comma
comma = "," + newline
ret += space * INDENT * (level+1)
#ret += '"' + str(k) + '"' + space + ':' + space
ret += '"' + str(k) + '":' + space
ret += to_json(v, level+1)
ret += newline + space * INDENT * level + "}"
elif o is None:
ret += "null"
else:
#raise TypeError("Unknown type '%s' for json serialization" % str(type(o)))
ret += str(o)
return ret
#main():
FOLD_LEVEL = 10000
INDENT = 4
parser = OptionParser(usage='%prog json_file [options]', version=VERSION)
parser.add_option("-f", "--fold-level", action="store", type="int",
dest="fold_level", help="int (all json is minimized to this level)")
parser.add_option("-i", "--indent", action="store", type="int",
dest="indent", help="int (spaces of indentation, default is 4)")
parser.add_option("-o", "--outfile", action="store", type="string",
dest="outfile", metavar="filename", help="write output to a file")
(options, args) = parser.parse_args()
if len(args) == 0:
infile = sys.stdin
elif len(args) == 1:
infile = open(args[0], 'rb')
else:
raise SystemExit(sys.argv[0] + " json_file [options]")
if options.outfile == None:
outfile = sys.stdout
else:
outfile = open(options.outfile, 'wb')
if options.fold_level != None:
FOLD_LEVEL = options.fold_level
if options.indent != None:
INDENT = options.indent
with infile:
try:
obj = json.load(infile)
except ValueError, e:
raise SystemExit(e)
with outfile:
outfile.write(to_json(obj))
outfile.write('\n')
The script accepts fold level, indent and output file from the command line:
$ jsonfold.py -h
Usage: jsonfold.py json_file [options]
Options:
--version show program's version number and exit
-h, --help show this help message and exit
-f FOLD_LEVEL, --fold-level=FOLD_LEVEL
int (all json is minimized to this level)
-i INDENT, --indent=INDENT
int (spaces of indentation, default is 4)
-o filename, --outfile=filename
write output to a file
To get my example from above, fold at the 5th level:
$ jsonfold.py test2 -f 5
{
"results": {
"groups": {
"alpha": {
"items": {
"pear": {"attributes":{"class":"fruit"}},
"apple": {"attributes":{"class":"fruit"}},
"dog": {"attributes":{"class":None}}
}
},
"beta": {
"items": {
"banana": {"attributes":{"class":"fruit"}}
}
}
}
}
}