[Python-ideas] Unify addresses passed to bind() and getaddrinfo()

Giampaolo Rodolà g.rodola at gmail.com
Thu Mar 14 15:04:50 CET 2013

Agreed, but now that I look at how getsockaddrarg() is implemented
into socketmodule.c I'm kind of scared of what could happen if we
blindly change/force the original tuple passed by the user in case of
exotic families such as AF_NETLINK, AF_BLUETOOTH and others (I have no
idea what kind of address tuple (?) is supposed be passed in those
Alternatively we might change it only for AF_INET sockets but it seems
kind of inconsistent and doesn't probably worth the effort.

--- Giampaolo

2013/3/13 Alex Stewart <foogod at gmail.com>:
> On Mon, Mar 11, 2013 at 12:20 PM, Giampaolo Rodolà <g.rodola at gmail.com>
> wrote:
>> It took me quite some time to figure out what was wrong as to me ""
>> has always been an alias for "all interfaces" and didn't know
>> getaddrinfo() behaved differently than bind() in this regard.
>> If from getaddrinfo() standpoint "" (empty string) has no particular
>> meaning I propose to unify the two APIs and make getaddrinfo() assume
>> "" is an alias for "all interfaces".
> I agree this difference in behavior seems a little confusing, and is
> arguably odd considering that bind() uses getaddrinfo() internally..
> At the very least, I do believe that if getaddrinfo() accepts None to
> indicate "all local interfaces", that bind() should also accept None for
> this purpose as well.  I don't think this would be a difficult change and I
> can't see any real downside to allowing it.  The only concern I see with
> going the other direction (making getaddrinfo() consider an empty string to
> be the same as None), as you suggest, is that this would technically not
> make it work the same as the underlying system call, which does treat "" and
> NULL as meaning different things.
> It is true that in the typical Unix/Windows/MacOS case using the standard
> hosts/DNS resolvers, an empty hostname has no real meaning, but technically
> that is not necessarily true for all possible types of name services that an
> OS might provide, and it is possible that there's a name resolver out there
> for which specifying "" as the hostname actually does mean something
> important.  Theoretically, this sort of change would make such a system not
> work as expected (possibly in non-obvious ways) when accessed from Python..
> Personally, though, I do think it would make sense to change bind() to allow
> None as an argument, and make that the preferred way to specify "all
> interfaces" (still allowing an empty string as another way to say the same
> thing).  It would make it more consistent with getaddrinfo, as well as also
> making it more Pythonic, IMHO..
> --Alex
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