Re: [Chicken-users] http-client: distinguishing between responses 301 and 302

[Norman Gray]

John, hello.

On 18 Oct 2018, at 20:49, John Cowan wrote:

> The difference between 301 and 302 is primarily relevant to crawlers 
> and
> caches.  I agree that it needs to exist, but not clear that a
> general-purpose client needs to expose it.  Can you explain your use 
> case
> more clearly?

It seems to me that the difference is relevant to users other than 
crawlers and caches.  As you know, 301 is saying 'this is the wrong URI; 
don't come here again', but 302 is saying 'this is the right URI; see 
over there for the details', and the difference between 'right URI' and 
'wrong URI' is significant.  A browser typically won't expose the 
distinction to its user in those terms, but the browser should be able 
to distinguish the cases.

Also, even if the distinction were indeed relevant only to caches and 
crawlers, if I want to implement a crawler in Chicken, then I need to 
have access to the distinct statuses.  It's reasonable that the default 
or simple behaviour is to blur the distinction, largely for the reason 
that you suggest, but in a general-purpose client, the information needs 
to be available somehow.

Also, as Jörg suggests in a message I see this one is crossing, I'm 
writing testing code at this point, so need to be able to see what the 
server actually said, rather than what the http-client library thinks it 
intended.

As Peter says, this was clearly just an oversight in the http-client 
library rather than a design decision.  Thanks, Peter: I'll be able to 
try the updated library shortly.

Though I understand why it was designed that way, it does feel slightly 
awkward to me that I'm having to use an exception-handling mechanism to 
get at this status distinction.  A follow-redirects? parameter would 
suit _my_ use-case very nicely, but I appreciate it may well have other 
consequences for the interface.  Similarly, a 'dumb' mode where the 
library treated 2xx, 3xx, 4xx and 5xx statuses the same way, would work 
very well for my case.

Best wishes,

Norman


--
Norman Gray  :  https://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK