Is there a way to extract the keys from JSON using jsonpath-ng?

Question

I want to create a list of keys from JSON (actually JSON Schema). JSON is complex and nested so I am using the jsonpath-ng library.

I can't manage to get the list of keys. On the other hand, extracting the values is successful with this syntax: print([match.value for match in tagNames]).

Attempt to extract the keys using similar syntax, like this...

from jsonpath_ng import jsonpath, parse
import json

filePath = "./sample.json"
with open(filePath, "r") as jsonFile:
    jsonData = json.load(jsonFile)

tagNames = parse("tags[*].*").find(jsonData)
print([match.key for match in tagNames])

returns this error:

AttributeError: 'DatumInContext' object has no attribute 'key'

although I am getting the 'key' suggestion after I type 'match.'

Example of JSON I work with:

{
"tags": [
    {
        "name": "auth",
        "description": "Authentication"
    },
    {
        "name": "b2b",
        "description": "B 2b"
    }
],
"paths": {
    "/rest/auth": {
        "post": {
            "tags": [
                "auth"
            ],
            "operationId": "generateToken",
            "consumes": [
                "application/json"
            ],
            "produces": [
                "*/*"
            ],
            "responses": {
                "200": {
                    "description": "Generated"
                },
                "201": {
                    "description": "Created"
                }
            }
        },
        "get": {
            "tags": [
                "status"
            ],
            "operationId": "check Token",
            "consumes": [
                "application/json"
            ],
            "produces": [
                "*/*"
            ],
            "responses": {
                "200": {
                    "description": "Generated"
                },
                "201": {
                    "description": "Created"
                }
            }
        }
    }
}

}

Task 1 - a simpler task of getting the keys under tags (expected result: name, description).

Task 2 - more complicated case is getting the keys from paths (expected result: post, get).

If jsonpath doesn't support extracting the keys, does anyone have any other suggestion for nested JSONs?

I also tried to convert the match result to plain python dict in order to get the keys with .keys(), but without success.

Answer 1

If I understand you correctly, you may be looking for something like this:

from jsonpath_ng import parse
import json
my_str = """[your json string above]"""
data = json.loads(my_str)

First expression:

sonpath_expr = parse('$.tags')
for d in jsonpath_expr.find(data):
    for k in d.value[0].keys():
        print(k)

Output:

name
description

Second expression:

jsonpath_expr = parse('$.paths..*..*')
for k in jsonpath_expr.find(data)[0].context.value.keys():
    print(k)

Output:

post
get