| 1 | """Base64 JSON helpers used by the protocol-shaped local transport.""" |
| 2 | |
| 3 | from __future__ import annotations |
| 4 | |
| 5 | import base64 |
| 6 | import json |
| 7 | from typing import Any |
| 8 | |
| 9 | from pydantic import BaseModel |
| 10 | |
| 11 | from .errors import ProtocolError |
| 12 | |
| 13 | |
| 14 | def encode_model(model: BaseModel) -> str: |
| 15 | """Serialize a model to standard Base64-encoded JSON.""" |
| 16 | |
| 17 | payload = model.model_dump_json(by_alias=True, exclude_none=True) |
| 18 | return base64.b64encode(payload.encode("utf-8")).decode("ascii") |
| 19 | |
| 20 | |
| 21 | def decode_json(value: str, *, header_name: str) -> dict[str, Any]: |
| 22 | """Decode a Base64 JSON header without leaking its raw value in errors.""" |
| 23 | |
| 24 | try: |
| 25 | decoded = base64.b64decode(value, validate=True) |
| 26 | payload = json.loads(decoded) |
| 27 | except (ValueError, UnicodeDecodeError, json.JSONDecodeError) as exc: |
| 28 | raise ProtocolError( |
| 29 | "malformed_protocol_header", |
| 30 | f"{header_name} is not valid Base64-encoded JSON.", |
| 31 | ) from exc |
| 32 | |
| 33 | if not isinstance(payload, dict): |
| 34 | raise ProtocolError( |
| 35 | "malformed_protocol_header", |
| 36 | f"{header_name} must decode to a JSON object.", |
| 37 | ) |
| 38 | return payload |