PyCDDL: A CDDL validation library for Python

CDDL is a schema language for the CBOR serialization format. pycddl allows you to validate CBOR documents match a particular CDDL schema, based on the Rust cddl library.

For example, here we use the cbor2 library to serialize a dictionary to CBOR, and then validate it:

from pycddl import Schema
import cbor2

uint_schema = Schema("""
    object = {
        xint: uint
    }
"""
)
uint_schema.validate_cbor(cbor2.dumps({"xint", -2}))

If validation fails, a pycddl.ValidationError is raised.

Reducing memory usage and safety constraints

In order to reduce memory usage, you can pass in any Python object that implements the buffer API and stores bytes, e.g. a memoryview() or a mmap object.

The passed-in object must be read-only, and the data must not change during validation! If you mutate the data while validation is happening the result can be memory corruption or other undefined behavior.

Release notes

0.5.1

• Upgrade to newer cddl crate, fixing some validation bugs.

0.5.0

• Support for ARM macOS.
• Dropped Python 3.7 support.

0.4.1

• Test fixes, with no user-relevant changes.

0.4.0

• validate_cbor() now accepts read-only buffers, not just bytes. This is useful if you want to e.g. validate a large file, since you can mmap() it.
• The GIL is released when parsing documents larger than 10KiB.

0.3.0

• Fixed major bug where if the document was valid UTF-8, the library would attempt to parse it as JSON!
• Added support for ARM macOS.

0.2.2

• Updated to cddl 0.9.1.

0.2.1

• Added PyPy wheels.

0.2.0

• Schemas are now only parsed once (when the Schema() object is created), instead of every time validation happens, which should improve validation performance.
• Updated to a newer version of underlying CDDL library, which should make CDDL parsing more compliant.
• Added a repr() implementation to Schema for easier debugging.

0.1.11

• Initial release.