feat: Implement validate_json()

A util func for validating a metadata
instance of a DANDI model against the
JSON schema of the model

dandischema/utils.py

@@ -1,13 +1,16 @@
 from __future__ import annotations
 
 import re
-from typing import Any, Iterator, List, Union, get_args, get_origin
+from typing import Any, Iterator, List, Union, cast, get_args, get_origin
 
+from jsonschema import Draft7Validator, Draft202012Validator
 from jsonschema.protocols import Validator as JsonschemaValidator
 from jsonschema.validators import validator_for
 from pydantic.json_schema import GenerateJsonSchema, JsonSchemaMode, JsonSchemaValue
 from pydantic_core import CoreSchema, core_schema
 
+from .exceptions import JsonschemaValidationError
+
 TITLE_CASE_LOWER = {
     "a",
     "an",
@@ -176,3 +179,41 @@ def jsonschema_validator(
 
     # Return a validator with format checking disabled
     return validator_cls(schema)
+
+
+def validate_json(instance: Any, schema: dict[str, Any]) -> None:
+    """
+    Validate a metadata instance of a **DANDI model** against the JSON schema of the
+    model
+
+    :param instance: The metadata instance to validate
+    :param schema: The JSON schema of the model
+
+    :raises JsonschemaValidationError: If the metadata instance is invalid, an instance
+        of this exception containing a list of `jsonschema.exceptions.ValidationError`
+        instances representing all the errors detected in the validation is raised
+    :raises jsonschema.exceptions.SchemaError: If the JSON schema is invalid
+    :raises ValueError: If the schema does not contain a 'schemaVersion' field
+    """
+    if "schemaVersion" not in schema:
+        raise ValueError("The schema must contain a 'schemaVersion' field")
+
+    default_validator_cls = cast(
+        type[JsonschemaValidator],
+        (
+            Draft202012Validator
+            # `"schemaVersion"` 0.6.5 and above is produced with Pydantic V2
+            # which is compliant with JSON Schema Draft 2020-12
+            if version2tuple(schema["schemaVersion"]) >= version2tuple("0.6.5")
+            else Draft7Validator
+        ),
+    )
+
+    validator = jsonschema_validator(
+        schema, check_format=True, default_cls=default_validator_cls
+    )
+
+    errs = sorted(validator.iter_errors(instance), key=str)
+
+    if errs:
+        raise JsonschemaValidationError(errs)