thebjorn thebjorn - 4 months ago 28
JSON Question

json query that returns parent element and child data?

Given the following json:

{
"README.rst": {
"_status": {
"md5": "952ee56fa6ce36c752117e79cc381df8"
}
},
"docs/conf.py": {
"_status": {
"md5": "6e9c7d805a1d33f0719b14fe28554ab1"
}
}
}


is there a query language that can produce:

{
"README.rst": "952ee56fa6ce36c752117e79cc381df8",
"docs/conf.py": "6e9c7d805a1d33f0719b14fe28554ab1",
}


My best attempt so far with JMESPath (http://jmespath.org/) isn't very close:

>>> jmespath.search('*.*.md5[]', db)
['952ee56fa6ce36c752117e79cc381df8', '6e9c7d805a1d33f0719b14fe28554ab1']


I've gotten to the same point with ObjectPath (http://objectpath.org):

>>> t = Tree(db)
>>> list(t.execute('$..md5'))
['952ee56fa6ce36c752117e79cc381df8', '6e9c7d805a1d33f0719b14fe28554ab1']


I couldn't make any sense of JSONiq (do I really need to read a 105 page manual to do this?) This is my first time looking at json query languages..

Answer

Missed the python requirement, but if you are willing to call external program, this will still work. Please note, that jq >= 1.5 is required for this to work.

# If single "key" $p[0] has multiple md5 keys, this will reduce the array to one key.
cat /tmp/test.json | \
jq-1.5 '[paths(has("md5")?) as $p | { ($p[0]): getpath($p)["md5"]}] | add '

# this will not create single object, but you'll see all key, md5 combinations
cat /tmp/test.json | \
jq-1.5 '[paths(has("md5")?) as $p | { ($p[0]): getpath($p)["md5"]}] '

Get paths with "md5"-key '?'=ignore errors (like testing scalar for key). From resulting paths ($p) filter and surround result with '{}' = object. And then those are in an array ([] surrounding the whole expression) which is then "added/merged" together |add

https://stedolan.github.io/jq/