How could I know which column caused `asyncpg.exceptions.UniqueViolationError`?

[wonderbeyond]

I want to directly know which column cause UniqueViolationError, but not from e.message or e.detail.

I need it because I want to build my own message to my API consumer.
Currently I just expose the UniqueViolationError.detail, which I think unsafe.

    try:
        ins_res = await app.db.fetchrow(user_tbl.insert().values(**user.to_native('create')))
    except UniqueViolationError as e:
        return json({'message': e.detail}, status=409)

• asyncpg version: 0.12.0
• PostgreSQL version: PostgreSQL 10.0 on x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18) 6.3.0 20170516, 64-bit
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: No; Yes
• Python version: 3.6.2
• Platform: Ubuntu 16.04.3/Linux 4.4.0-97-generic
• Do you use pgbouncer?: I dont know
• Did you install asyncpg with pip?: not exactly, I use pipenv
• If you built asyncpg locally, which version of Cython did you use?: No
• Can the issue be reproduced under both asyncio and
  uvloop?: Not tested

[elprans]

Inspecting exception attributes is the correct (and only) way of determining the details of the exception.

asyncpg doesn't do any interpretation of the exception, it just maps the SQLCODE to a class and unpacks the attributes as sent by the server.

[wonderbeyond]

You mean I can only parse the exception message, with the risk of format change?

[elprans]

Yes, you have to parse. Exception attributes is the finest level of structured error information currently provided by PostgreSQL.