CustomSerializer Class — langchain Architecture

Source Code

libs/standard-tests/langchain_tests/conftest.py lines 20–52

class CustomSerializer:
    """Custom serializer for VCR cassettes using YAML and gzip.

    We're using a custom serializer to avoid the default yaml serializer
    used by VCR, which is not designed to be safe for untrusted input.

    This step is an extra precaution necessary because the cassette files
    are in compressed YAML format, which makes it more difficult to inspect
    their contents during development or debugging.
    """

    @staticmethod
    def serialize(cassette_dict: dict[str, Any]) -> bytes:
        """Convert cassette to YAML and compress it."""
        cassette_dict["requests"] = [
            {
                "method": request.method,
                "uri": request.uri,
                "body": request.body,
                "headers": {k: [v] for k, v in request.headers.items()},
            }
            for request in cassette_dict["requests"]
        ]
        yml = yaml.safe_dump(cassette_dict)
        return gzip.compress(yml.encode("utf-8"))

    @staticmethod
    def deserialize(data: bytes) -> dict[str, Any]:
        """Decompress data and convert it from YAML."""
        decoded_yaml = gzip.decompress(data).decode("utf-8")
        cassette = cast("dict[str, Any]", yaml.safe_load(decoded_yaml))
        cassette["requests"] = [Request(**request) for request in cassette["requests"]]
        return cassette