Migrating from Python jsonschema. Guidance sought

[jpgoldberg]

I am a little lost looking for the documentation for the Python bindings, and in particular, I would appreciate some guidance on moving to this from the Python jsonschema library.

[Stranger6667]

Hi @jpgoldberg

I'll write a proper migration guide, but here are the main differences:

Order of arguments:

try:
    jsonschema_rs.validate({"type": "object"}, {"name": "John"})  # Note: schema first, instance second
except ValidationError as e:
    print(e.message)

Custom format checks:

# jsonschema
from jsonschema import Draft7Validator, FormatChecker

format_checker = FormatChecker()

@format_checker.checks("custom-format")
def check_custom(value):
    return value.startswith("custom-")

validator = Draft7Validator(schema, format_checker=format_checker)

# jsonschema-rs
from jsonschema_rs import Draft7Validator

def check_custom(value: str) -> bool:
    return value.startswith("custom-")

validator = Draft7Validator(
    schema,
    formats={"custom-format": check_custom},
    validate_formats=True,
)

ValidationError differences

# jsonschema
error.message          # Error message
error.path             # deque(['field', 0])
error.schema_path      # deque(['properties', 'field', 'type'])
error.validator        # 'type'
error.validator_value  # 'string'

# jsonschema-rs
error.message          # Error message
error.instance_path    # ['field', 0]
error.schema_path      # ['properties', 'field', 'type']
error.kind             # ValidationErrorKind.Type(types=['string'])
error.instance         # The actual invalid value

Schema validation:

# jsonschema
from jsonschema import Draft7Validator

Draft7Validator.check_schema(schema)  # Raises SchemaError if invalid

# jsonschema-rs
import jsonschema_rs

jsonschema_rs.meta.validate(schema)   # Raises ValidationError if invalid

Schema validity is also checked during validator creation process.

$ref resolution is inspired by referencing which is used by jsonschema under the hood, so the migration path there should be similar.

jsonschema-rs does not support:

• Recursive python objects
• error.context (error.kind has some overlap with this though)
• Validator.evolve

let me know what aspects are specifically interesting for you, I'll answer here and later will include it into the migration guide.

[Stranger6667]

Guide - https://github.com/Stranger6667/jsonschema/blob/master/crates/jsonschema-py/MIGRATION_FROM_JSONSCHEMA.md