Transformations on JSON schemas. Also strictness.

gistfile1.py

def rec_schema_transform(transform):
    def recur(schema):
        if not isinstance(schema, dict):
            return
        transform(schema)
        for k, v in schema.items():
            if k in ("properties", "patternProperties", "dependencies"):
                for _, subschema in v.items():
                    recur(subschema)
            elif k in ("additionalProperties", "additionalItems") and v:
                recur(v)
            elif k == "items":
                if isinstance(v, list):
                    for subschema in v:
                        recur(subschema)
                else:
                    recur(v)
        return schema
    return recur

@rec_schema_transform
def make_strict(schema):
    if "properties" in schema and "additionalProperties" not in schema:
        schema["additionalProperties"] = False
    if "required" not in schema:
        schema["required"] = True

make_strict takes a JSON schema (as documented here: http://tools.ietf.org/html/draft-zyp-json-schema-03#section-5.8) and makes it default to strict -- makes all properties required and all non-specified properties forbidden. All valid JSON schema are still expressible, this just makes the strict ones shorter.

Yes, this'll mutate the value passed in rather than just creating a new schema and returning it. Seemed like the idiomatic way to do it in Python.