bytex 0.2.0

Pydantic-like binary validation

bytex

Like Pydantic, but for binary formats.

Installation

$ pip install bytex

Example

Let’s say you want to represent a user profile in your application using a compact binary format.

Start by defining the user type as a StructureEnum:

from bytex import StructureEnum
from bytex.types import U8
from enum import auto


class UserType(StructureEnum(U8)):
    """
    An enum representing a UserType in a single byte.
    """
    ADMIN = auto()
    MEMBER = auto()
    GUEST = auto()

A StructureEnum is just a subclass of Python's built-in Enum, so you can use it as you normally would.

Then define a structure for a date:

from bytex import Structure
from bytex.types import U16, U8


class Date(Structure):
    year: U16
    month: U8
    day: U8

Now bring it all together into a UserProfile structure:

from bytex import Structure
from bytex.length_encodings import Terminator
from typing import Annotated


class UserProfile(Structure):
    user_type: UserType
    joined_at: Date
    name: Annotated[str, Terminator("\0")]

The Annotated[str, Terminator("\0")] represents a string with a Terminator length encoding, meaning the string is serialized with a "\0" at the end, and deserialized until a "\0" is encountered (There is a pre-made type for this exact scenario called CStr located at structure.types, which is a null-terminated string).

And you're done!

You can now serialize and parse binary data with ease:

from bytex import Endianness

profile = UserProfile(
    user_type=UserType.ADMIN,
    joined_at=Date(year=2024, month=6, day=25),
    name="admin"
)

binary: bytes = profile.dump(endianness=Endianness.LITTLE)
parsed: UserProfile = UserProfile.parse(binary, endianness=Endianness.LITTLE)