Re: with-url

[Yuri Khan]

On Sun, Jan 22, 2017 at 5:07 AM, Lars Ingebrigtsen <address@hidden> wrote:

> The network is transient.  These events are expected.  That the file
> you've just examined isn't there is a different class of error.

I work on the server-side team of a network interaction where all of
the errors mentioned upthread can and do occur: DNS failure,
connection timeout, connection refusal, 4xx and 5xx status codes, *and
also* 3xx codes with redirects to unexpected locations and 2xx codes
with an unexpected Content-Type or malformed content.

We constantly have to remind our client-side team that they need to be
prepared for all of those, and that their QA must test each of those.
Whenever they forget to do that, horrible things happen, up to and
including application startup failure requiring reinstallation.

A good HTTP client framework *should* signal errors and let the
willing client catch them, rather than leave it to the client to
explicitly check for every error condition. Myers’ Razor: Make
interfaces easy to use correctly and hard to use incorrectly.

The only class of HTTP client applications that I know where the
expected way to process failure responses is the same as for success
responses is the web browser. And I don’t envision *very* many of
these written in Elisp.