Add Binary constructor and bytes parameter serialization

[bgunebakan]

PEP 249 (DB-API 2.0) specifies that drivers should provide a Binary(string) type constructor for working with binary data. crate-python currently omits it, and passing raw bytes as a SQL parameter raises TypeError from orjson because json_encoder() has no handler for bytes.

Current behaviour

Create a table with binary columns:

CREATE TABLE t_binary (flags BIT(8))

conn = crate.client.connect("localhost:4200")
cur = conn.cursor()
cur.execute("INSERT INTO t_binary (data) VALUES (?)", (b"\x00\xff",))
# TypeError: Type is not JSON serializable: bytes

Root cause

json_encoder() in src/crate/client/http.py covers Decimal, datetime, date, and time, but not bytes. There is also no Binary symbol exported from the module.

Notes

• This implementation is needed to implement Types: Add support for BINARY columns sqlalchemy-cratedb#12

[amotl]

Hi Bilal. Thank you for investigating. Because CrateDB does not provide a data type for storing bytes, the driver or another layer would need to encode/decode to/from an Unicode-safe representation and store the data into a STRING column, like this other patch tries to exercise it with SQLAlchemy.

• Types: Add support for BINARY columns sqlalchemy-cratedb#12

I don't know how this would work on the DBAPI driver level, but if you see a way to support the feature right here, and use it for building the SQLAlchemy support upon, we will be more than happy.