Re: Conditional INSERT

On Fri, Mar 15, 2019 at 11:59 AM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 3/15/19 11:54 AM, basti wrote:
> > this is a dns database, and the client is update the _acme-challenge for
> > LE certificates. I don't want that the client can insert "any" txt
> record.
> > the client should only insert data if the hostname start with
> > _acme-challenge. i have no control on client.
> >
> > i have try this rule but the server reject this with a endless loop:
>
> To borrow a quote:
>
> "I had a problem so I decided to use a rule, now I have two problems."
>
> Do not use a rule. As suggested upstream use a BEFORE INSERT trigger,
> you will be a lot happier.
>
> >
> > CREATE RULE insert_acme AS ON INSERT TO t_dnsadmin_records_txt
> > WHERE NEW.hostname like '_acme-challenge%'
> > DO INSERT INTO t_dnsadmin_records_txt VALUES (
> > NEW.domainid,
> > NEW.hostname,
> > NEW.txtdata
> > );
> >
> >
>

Just curious, but wanted to follow up on whether rules are across-the-board
discouraged? I've seen disparaging comments about them, but I don't see
any indication of that on the create rule page.

The other suggestion in this thread--a foreign key--will throw an error.
Your suggestion of a before trigger might well be better (and if so, why?),
but is there anything particularly wrong or bad about using a rule that
would actually work? Something along these lines:

CREATE RULE insert_acme AS ON INSERT TO t_dnsadmin_records_txt
WHERE NOT NEW.hostname like '_acme-challenge%'
DO INSTEAD NOTHING;

Thanks,
Ken

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