Re: libpq compression

On Jun20, 2012, at 17:34 , Tom Lane wrote:
> Florian Pflug <fgp@phlo.org> writes:
>> I wonder though if shouldn't restrict the allowed ciphers list to being
>> a simple list of supported ciphers. If our goal is to support multiple
>> SSL libraries transparently then surely having openssl-specific syntax
>> in the config file isn't exactly great anyway...
> 
> No, we don't want to go there, because then we'd have to worry about
> keeping the default list in sync with what's supported by the particular
> version of the particular library we chance to be using.  That's about
> as far from transparent as you can get.  A notation like "DEFAULT"
> is really quite ideal for our purposes in that respect.

No argument with that, but does that mean we have to allow the full
syntax supported by OpenSSL (i.e., those +,-,! prefixes)? Maybe we could
map an empty list to DEFAULT and otherwise interpret it as a list of 
ciphers?

It'd make the whole NULL-cipher business easy, because once we know that
the cipher specified doesn't contain !NULL (which removes NULL *permanently*),
we can simply append NULL to allow "all these ciphers plus NULL".

best regards,
Florian Pflug