Following up on the answer @chris-w provided, I wanted to do this same thing with jsonschema 3.2.0 but his answer didn't quite cover it I hope this answer helps those who are still coming to this question for help but are using a more recent version of the package.
To extend a JSON schema using the library, do the following:
- Create the base schema:
base.schema.json
{
"$id": "base.schema.json",
"type": "object",
"properties": {
"prop": {
"type": "string"
}
},
"required": ["prop"]
}
- Create the extension schema
extend.schema.json
{
"allOf": [
{"$ref": "base.schema.json"},
{
"properties": {
"extra": {
"type": "boolean"
}
},
"required": ["extra"]
}
]
}
- Create your JSON file you want to test against the schema
data.json
{
"prop": "This is the property",
"extra": true
}
- Create your RefResolver and Validator for the base Schema and use it to check the data
#Set up schema, resolver, and validator on the base schema
baseSchema = json.loads(baseSchemaJSON) # Create a schema dictionary from the base JSON file
relativeSchema = json.loads(relativeJSON) # Create a schema dictionary from the relative JSON file
resolver = RefResolver.from_schema(baseSchema) # Creates your resolver, uses the "$id" element
validator = Draft7Validator(relativeSchema, resolver=resolver) # Create a validator against the extended schema (but resolving to the base schema!)
# Check validation!
data = json.loads(dataJSON) # Create a dictionary from the data JSON file
validator.validate(data)
You may need to make a few adjustments to the above entries, such as not using the Draft7Validator. This should work for single-level references (children extending a base), you will need to be careful with your schemas and how you set up the RefResolver and Validator objects.
P.S. Here is a snipped that exercises the above. Try modifying the data string to remove one of the required attributes:
import json
from jsonschema import RefResolver, Draft7Validator
base = """
{
"$id": "base.schema.json",
"type": "object",
"properties": {
"prop": {
"type": "string"
}
},
"required": ["prop"]
}
"""
extend = """
{
"allOf": [
{"$ref": "base.schema.json"},
{
"properties": {
"extra": {
"type": "boolean"
}
},
"required": ["extra"]
}
]
}
"""
data = """
{
"prop": "This is the property string",
"extra": true
}
"""
schema = json.loads(base)
extendedSchema = json.loads(extend)
resolver = RefResolver.from_schema(schema)
validator = Draft7Validator(extendedSchema, resolver=resolver)
jsonData = json.loads(data)
validator.validate(jsonData)
jsonschema.RefResolver(None, referrer=None, store=schema_store). And then the store has entries with an "$id" field like:"https://example.com/path/subpath/filename.json". (This doesn't require any network calls--unless you specify a schema not in the store--since the store contains a cache of any reference we need). – Cockaigne