[Mailman-Developers] PHP Wrappers?
brad at stop.mail-abuse.org
Tue Nov 22 20:13:39 CET 2005
At 5:18 PM +0900 2005-11-22, Stephen J. Turnbull wrote:
> To get all the way to "MTA doesn't accept anything that MM is going to
> refuse to deliver", yes. But we certainly could define an interface
> to an auxiliary service such that if the MTA tells us (AuthType,
> AuthCredentials, EnvelopeSender, Sender, From, To) we'll say "nuke it"
> or "OK, we'll handle that". That would allow us to push a lot of
> simple cases (such as "authenticated user not a list member") back to
> the MTA, and never invoke the heavy equipment of Mailman itself.
The problem is that this process is basically what Mailman goes
through anyway, and I don't see any reason why we would want to
develop code to duplicate all that functionality -- you'd still have
to touch all the same Python pickles, deal with file locking
contention, etc.... Moreover, that's going to be a heavy process,
and MTAs have some very tight constrictions upon them to get a
response back to the sender in a reasonable amount of time.
I agree that the feature is desirable, but short of a complete
ground-up rewrite, I don't see any way to do it. Morever, as stated
in my previous response, I think that a lot of thought needs to go
into this before we even get to the design stage.
Given that MM3 is already early in the implementation phase, we
may have to wait quite a bit longer, especially since the designers
and developers are few and far between, and what time they have is
already very tightly spread.
> Not "have to", but that may be the most effective way to jump start
> it, may even be necessary for jump starting. It's not our "job", but
> it's something we may need to budget resources for if we want to do
> it. Of course if those resources are large and won't come from fresh
> blood, that kills the idea. But we haven't shown that the needed
> resources are large, and there are a couple of people who I don't
> recognize as frequent code contributors who are pushing hard---there
> might be fresh blood out there to do this.
If there are people who want to push forward on this now, I think
they'll have to wait until the specifications and design phase are
done, before they can start hacking on their favourite MTAs. Either
that, or everyone starts inventing their own APIs and hacking their
MTAs to support those APIs, and then we'll have a half-dozen
different competing solutions that we've got to try to support.
People should definitely get some real-world experience in how to
do this sort of stuff, but no one should have any real hope of
getting their personal pet version incorporated into Mailman. The
Mailman developers might take advantage of their experience in
designing their own API, but that's about as far as they could hope
> Was it? I don't know. My feeling is that Ian is lacking some
> necessary facts, and consequently expressed his requirements in terms
> that can't be satisfied. But if we give him the details and withhold
> judgment on the substance until he's reformulated, we might find that
> what he really wants is a lot closer to what would be do-able than our
> initial impressions are.
Okay, fair enough. Let's give him time to re-formulate what he's
> I think so. Solving them for Ian probably is not too hard.
That depends on what MTA Ian is using, and how much code in the
MTA that Ian is willing (and able) to hack himself, or get someone
else to hack for him. Likewise, there will probably be a fair amount
of hacking on Mailman that would need to be done to support his
particular requirements, and a lot would depend on who's going to be
doing that hacking and how much time (and experience) they've got to
put towards that effort.
> them in a way that generalizes is going to be hard. But Python is a
> very good environment for such generalization.
The Python part is not the hard part of the equation. The hard
parts of the equation are going to be the API specification and
design process, hacking on the MTA code, etc....
> Well, you may have a bigger problem in mind, but 90% of Mailman users
> would get a big bonus from getting only halfway there. Or maybe you
> know something I don't.
I disagree. I don't think a 50% solution is going to help many
people, and it certainly won't help them for long.
It will just push out the event horizon a bit, and since we have
exponential growth of spam and other forms of mail abuse, it's going
to be a very short period of time before we're right back where we
were -- and where there are no more easy 50% solutions possible, and
where we have yet to spend any time stepping back from the problem a
bit and working on a better 80-90% solution.
> Of course you meant something substantially weaker than "all
> MTAs must understand as an absolute requirement", but surely it was
> something at least as strong as "we cannot ask users to change MTAs to
> get this feature." Agreed?
If they're using any of the mainstream MTAs, then they should be
able to expect that they can use virtually all of the features of
Mailman. They might be able to use other programs to fulfill other
components of the system (e.g., the people who use mhonarc instead of
pipermail), but that should be an optional additional extra
enhancement that they can add to the base system.
As I see it, the kind of thing you're talking about would be a
core component, one that could not be easily changed or substituted,
and if it's going to be useful at all it will need to support all the
major MTAs -- or be supported by them.
> Speaking for myself, I see nothing wrong with asking the bleeding edge
> adopters to change MTAs, and I see nothing wrong with restricting
> Mailman-supplied MTA code to a couple of MTAs that we "like". Of
> course we help other MTAs to incorporate the feature, but we don't
> need to promise that they can use it in advance. Some MTAs may never
> get it.
The problem is that there are way too many whackos who then take
those bleeding edge features and throw them into CPanel or a
vendor-proprietary version, and then dump off the after-sales support
And way too many whackos will take whatever code is available and
blindly install it, without really understanding that they need to
have a certain minimum level of competence before they take bleeding
edge code and try to start working with it.
Many vendors restrict who has access to development beta code,
and for good reason. If you're a MM3 developer or want to be, then
you should be free to play with that code about as much as you want
-- after all, the only risk should be to you and your mailing lists.
But you should anticipate that many people may expect you to hack
on the code yourself to fix whatever problems you may end up creating
> OTOH, I wonder if you're not overestimating the degree of difficulty
> and underestimating the benefits of the structural work required.
I don't think I'm underestimating the benefits of the structural
work. We won't know whether I'm overestimating the degree of
difficulty until the actual work is done and we can look back and see
what it took to get where we did.
> The "database backend" is _not_ structured that way yet,
Which is a large component of my caution on this topic. Code
hacking is easy. Database hacking is harder, because you've not only
got to hack the code which accesses the database, but also the
database structures that would be accessed. More importantly, since
you're talking about exposing some aspect of this database structure
to the outside world, you can't just take the easy way out and
directly access everything but you instead have to work through a
published API layer.
In programming, global variables make a lot of things easier in
one aspect, but they greatly complicate life in others. It takes
more work to write code in such a way to avoid global variables, but
in the end it usually pays off.
Working through published API layers has a lot of benefits too,
but it also takes a lot more work to make that happen -- compare the
classic C version of "Hello, world" to what you have to do to get the
same results with a standard X11 library. The source of the X11
version is likely to be many times larger than the compiled code of
the C version.
In this case, you're asking us to create the equivalent of the
X11 API and library, plus the associated database structures, etc....
Yes, we most likely have a smaller overall problem space, but we
also have many fewer programmers, each of whom is probably spending
less time on this work, and there are many classes of pre-existing
programs that we will have to somehow find interoperability with.
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
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