Failure passing string filters in additional_table_filters settings param when calling .query

[ryftrus]

Describe the bug

Passing the additional_table_filters with a string filter, fails to handle the escaping of single quotes correctly, and crashes instead, making it impossible to pass query filters that contain strings.

Steps to reproduce

1. Setup a Clickhouse machine
2. Add a table with a string field
3. Perform a query passing additional_table_filters for the string with a filter

Expected behaviour

The query will work with the filter applied

Code example

from clickhouse_connect import get_client
ch = get_client(...)
ch.query("CREATE OR REPLACE TABLE my_table (
      a String
    )")
ch.query("INSERT INTO my_table (a) VALUES ('some_value');")

ch.query(
    "SELECT a from my_table", settings={"additional_table_filters": {"a":"'some_value'"} 
)

clickhouse-connect and/or ClickHouse server logs

self = <clickhouse_connect.driver.httpclient.HttpClient object at 0x1220c6180>, response = <urllib3.response.HTTPResponse object at 0x12395f970>, retried = False

def _error_handler(self, response: HTTPResponse, retried: bool = False) -> None:
    if self.show_clickhouse_errors:
        try:
            err_content = get_response_data(response)
        except Exception:  # pylint: disable=broad-except
            err_content = None
        finally:
            response.close()

        err_str = f'HTTPDriver for {self.url} returned response code {response.status}'
        err_code = response.headers.get(ex_header)
        if err_code:
            err_str = f'HTTPDriver for {self.url} received ClickHouse error code {err_code}'
        if err_content:
            err_msg = common.format_error(err_content.decode(errors='backslashreplace'))
            if err_msg.startswith('Code'):
                err_str = f'{err_str}\n {err_msg}'
    else:
        err_str = 'The ClickHouse server returned an error.'

  raise OperationalError(err_str) if retried else DatabaseError(err_str) from None

E clickhouse_connect.driver.exceptions.DatabaseError: HTTPDriver for http://localhost:8123 received ClickHouse error code 26
E Code: 26. DB::Exception: Cannot parse quoted string: expected opening quote ''', got '"'. (CANNOT_PARSE_QUOTED_STRING) (version 25.4.1.2934 (official build))

../.venv/lib/python3.12/site-packages/clickhouse_connect/driver/httpclient.py:395: DatabaseError

Configuration

Environment

• clickhouse-connect version: 0.8.15
• Python version: 3.12.11
• Operating system: MacOS Sonoma 14.5

ClickHouse server

• ClickHouse Server version: 25.4.1
• ClickHouse Server non-default settings, if any:
• CREATE TABLE statements for tables involved:
• Sample data for these tables, use clickhouse-obfuscator if necessary
  Any table with string field.
  CREATE OR REPLACE TABLE my_table (
  a String
  )
  INSERT INTO my_table (a) VALUES ('some_value');

[genzgd]

There are several things going on here:

• First, any values used in the query settings are just passed as strings via a URL parameter. clickhouse-connect doesn't do any escaping of settings values (unlike binding values actually in the query). So what happens is the dictionary you are passing is converted to a string according to Python rules, and it will passed to clickhouse like this: &additional_table_filters={'a': "'some_value'"}. It's Python that's adding the surrounding double quotes to a value with single quotes when rendering a whole dictionary as a string.
• Accordingly, any setting like this you want to pass should be the way that ClickHouse will expect a string. Very few settings actually include an entire dictionary (this is the first one I've seen, and to be honest, I've never seen this setting before), but if you want to use such a setting, for the moment you'll have to construct the string yourself. Eventually clickhouse-connect could try to escape a settings that's a dictionary for you, but that's basically an enhancement request.
• So the way to do this current is to pass the string that ClickHouse expects. The way I eventually got this to work as you intend was this:

ch.query("SELECT a from my_table", settings={"additional_table_filters": "{'my_table':'a = ''some_value'''}"})

• This uses the ClickHouse "map" format, and uses a double ' to escape the single quotes.
• The final thing is that the key to additional_table_filters has to be the name of the table, and the value is a boolean SQL expression. Your example of {"a":"'some_value'"} will not work. It applies to table a, not my_table, and 'some_value' isn't a boolean expression.

I'll keep this open as an enhancement to eventually escape 'non-string' settings values, but it's definitely an edge use case.