Get presigned URL for select_object_content

[stephteo]

Hi, I'm trying to generate a presigned URL for "select_object_content" ClientMethod. In the docs, it says to pass the Params as normally passed to ClientMethod, but I get a JSONDecodeError: Expecting value: line 1 column 1 (char 0) upon doing so. Here is the code to reproduce:

request_url = s3_client.generate_presigned_url(
    ClientMethod="select_object_content",
    Params=dict(
        Bucket=bucket,
        Key=key,
        ExpressionType="SQL",
        Expression=f"select s.* from S3Object s limit 10",
        InputSerialization={"Parquet": {}},
        OutputSerialization={"JSON": {}},
    ),
    HttpMethod="GET",
) 

If I try to send InputSerialization and OutputSerialization as JSON strings, I get a ParamValidationError: Parameter validation failed: Invalid type for parameter InputSerialization, value: {"Parquet": {}}, type: <class 'str'>, valid types: <class 'dict'> Invalid type for parameter OutputSerialization, value: {"JSON": {}}, type: <class 'str'>, valid types: <class 'dict'>

request_url = s3_client.generate_presigned_url(
    ClientMethod="select_object_content",
    Params=dict(
        Bucket=bucket,
        Key=key,
        ExpressionType="SQL",
        Expression=f"select s.* from S3Object s limit 10",
        InputSerialization='{"Parquet": {}}',
        OutputSerialization='{"JSON": {}}',
    ),
    HttpMethod="GET",
) 

What is the proper way to pass in InputSerialization and OutputSerialization?