How to check JSON format validation?

Question

My program gets a JSON file that has an information for service.
Before run the service program, I want to check if the JSON file is valide(Only check whether all necessary keys exist).
Below is the standard(necessary datas) JSON format for this program:

{
    "service" : "Some Service Name"
    "customer" : {
        "lastName" : "Kim",
        "firstName" : "Bingbong",
        "age" : "99",
    }
}

Now I am checking the JSON file validation like this:

import json

def is_valid(json_file):

    json_data = json.load(open('data.json'))

    if json_data.get('service') == None:
        return False
    if json_data.get('customer').get('lastName') == None:
        return False
    if json_data.get('customer').get('firstName') == None:
        return False
    if json_data.get('customer').get('age') == None:
        return False

    return True

Actually, the JSON standard format has more than 20 keys. Is there any other way to check the JSON format?

Answer 1

You might consider jsonschema to validate your JSON. Here is a program that validates your example. To extend this to your "20 keys", add the key names to the "required" list.

import jsonschema
import json

schema = {
    "type": "object",
    "properties": {
        "customer": {
            "type": "object",
            "required": ["lastName", "firstName", "age"]}},
    "required": ["service", "customer"]
}

json_document = '''{
    "service" : "Some Service Name",
    "customer" : {
        "lastName" : "Kim",
        "firstName" : "Bingbong",
        "age" : "99"
    }
}'''

try:
    # Read in the JSON document
    datum = json.loads(json_document)
    # And validate the result
    jsonschema.validate(datum, schema)
except jsonschema.exceptions.ValidationError as e:
    print("well-formed but invalid JSON:", e)
except json.decoder.JSONDecodeError as e:
    print("poorly-formed text, not JSON:", e)

Resources:

• https://pypi.python.org/pypi/jsonschema
• http://json-schema.org/example1.html

Answer 2

First, don’t check for None using if x == None, use if x is None

You might try to simplify it slightly by checking the keys using set(json_data.keys()) == set(key1, key2, ...)

That would need to be repeated for any nested dictionaries in your json structure. Using sets instead of lists has the benefit of sets being unordered so it doesn’t matter the order of the data in your json.