From: Dmitry Gutov <dgutov@yandex.ru>
To: Lars Ingebrigtsen <larsi@gnus.org>
Cc: emacs-devel@gnu.org
Subject: Re: with-url
Date: Sat, 21 Jan 2017 23:26:07 +0300 [thread overview]
Message-ID: <e6b14926-f56c-55b0-3d7f-388fda9580ac@yandex.ru> (raw)
In-Reply-To: <87bmv0beoa.fsf@gnus.org>
On 21.01.2017 18:44, Lars Ingebrigtsen wrote:
> Nope. You should only signal an error if you have an error, and getting
> a 404 isn't an error.
Whether 404 is an error or not, depends on an application. And I'm
saying that as someone with a few years of experience writing web
applications that do HTTP requests themselves.
Consider the case where an application calls a function foo (which
implements some sort of abstraction layer), and the said function uses
with-url.
If foo is supposed to be general purpose (used in different
applications), it would have to handle errors in a general way, so that
any of its callers could still handle any kinds of errors, without being
a macro. I'd rather with-url (or its replacement) was an example of
doing that already.
>> Something else I take an issue with, is with `with-url' being a
>> macro. :) That violates The First Rule of Macro Club.
>
> Yes, the first rule is "use a macro when it makes sense".
Not really. And macros make sense the most when we add a control flow
construct, or some sort of definition syntax for a new facility. Neither
of which is really the case here.
You're basically joining a library function with a control flow
construct together.
>> 2) Basically require to use the newly-introduced threads for
>> asynchrony.
>
> Using the new threads is a trivial rewrite and doesn't affect the
> signature of the macro.
It could simplify it, by allowing to treat asynchronous code like
synchronous one.
> Anyway, I think the best option here would be to just have an
> :ignore-errors parameter to `with-url'. In that case, the body will
> just be evaluated if we get non-error response.
I'm rather more worried about being able to handle errors in an
asynchronous fashion.
You could say 404 is not an error, but handling it in a similar way to
all other "actual" errors like "can't resolve the hostname" and
"connection timeout" can be pretty handy.
next prev parent reply other threads:[~2017-01-21 20:26 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-29 0:41 with-url Lars Ingebrigtsen
2016-12-29 1:06 ` with-url Stefan Monnier
2016-12-29 1:12 ` with-url Lars Ingebrigtsen
2016-12-29 16:05 ` with-url Eli Zaretskii
2016-12-29 16:35 ` with-url Lars Ingebrigtsen
2016-12-29 16:40 ` with-url Lars Ingebrigtsen
2016-12-29 16:58 ` with-url Eli Zaretskii
2016-12-29 18:52 ` with-url Lars Ingebrigtsen
2016-12-29 20:31 ` with-url Eli Zaretskii
2016-12-30 14:12 ` with-url Lars Ingebrigtsen
2016-12-30 15:23 ` with-url Lars Ingebrigtsen
2016-12-30 16:58 ` with-url Eli Zaretskii
2017-01-21 15:31 ` with-url Lars Ingebrigtsen
2017-01-21 15:33 ` with-url Lars Ingebrigtsen
2017-01-21 15:54 ` with-url Eli Zaretskii
2017-01-21 16:32 ` with-url Lars Ingebrigtsen
2017-01-21 16:40 ` with-url Eli Zaretskii
2017-01-22 15:55 ` with-url Lars Ingebrigtsen
2017-01-22 16:39 ` with-url Eli Zaretskii
2016-12-29 16:53 ` with-url Eli Zaretskii
2016-12-29 18:48 ` with-url Lars Ingebrigtsen
2017-01-01 1:07 ` with-url Dmitry Gutov
2017-01-03 17:47 ` with-url Stefan Monnier
2017-01-26 23:00 ` with-url Ted Zlatanov
2017-01-26 23:08 ` with-url Lars Ingebrigtsen
2017-01-27 13:49 ` with-url Ted Zlatanov
2017-01-21 15:44 ` with-url Lars Ingebrigtsen
2017-01-21 20:26 ` Dmitry Gutov [this message]
2017-01-21 20:32 ` with-url Lars Ingebrigtsen
2017-01-21 20:36 ` with-url Dmitry Gutov
2017-01-21 20:49 ` with-url Lars Ingebrigtsen
2017-01-21 21:05 ` with-url Dmitry Gutov
2017-01-21 21:12 ` with-url Lars Ingebrigtsen
2017-01-21 21:16 ` with-url Dmitry Gutov
2017-01-21 21:23 ` with-url Lars Ingebrigtsen
2017-01-21 21:27 ` with-url Dmitry Gutov
2017-01-21 21:37 ` with-url Lars Ingebrigtsen
2017-01-21 21:54 ` with-url Dmitry Gutov
2017-01-21 22:07 ` with-url Lars Ingebrigtsen
2017-01-22 12:14 ` with-url Yuri Khan
2017-01-22 14:46 ` with-url Lars Ingebrigtsen
2017-01-22 15:13 ` with-url Dmitry Gutov
2017-01-22 16:36 ` with-url Eli Zaretskii
2017-01-22 21:27 ` with-url Dmitry Gutov
2017-01-22 14:22 ` with-url Dmitry Gutov
2017-01-22 14:42 ` with-url Lars Ingebrigtsen
2017-01-21 20:34 ` with-url Lars Ingebrigtsen
2017-01-21 20:38 ` with-url Dmitry Gutov
2017-01-21 20:48 ` with-url Lars Ingebrigtsen
2017-01-21 22:25 ` with-url John Mastro
2017-01-22 16:04 ` with-url Lars Ingebrigtsen
2017-01-22 16:42 ` with-url Eli Zaretskii
2017-01-22 16:55 ` with-url Lars Ingebrigtsen
2017-01-22 23:56 ` not with-url Richard Stallman
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