Re: url-fetch with referer

[Ludovic Courtès]

Pierre Neidhardt <address@hidden> skribis:

> Ludovic Courtès <address@hidden> writes:
>
>> More generally, we’ve added a couple of HTTP headers for issues that
>> were relatively common.  We could easily fix this one, but maybe you
>> could first talk to the webmasters, because requiring ‘Referer’ sounds
>> obnoxious; WDYT?
>
> So I did for 1 website and the answer was that this is on purpose, to
> "avoid linking directly to the archive from a different website."  A
> rather delusional enforcement, but hey, if we can't convince the webmasters...
>
> How would we add the relevant HTTP header then?

See ‘http-fetch’ in (guix build download).

(It would be more convincing if this is for a package to be included in
Guix proper, hint hint. :-))

>> (Note that in the meantime you can always work around the problem by
>> writing your own fixed-output derivation.)
>
> I don't understand, can you explain?

You could write something like:

--8<---------------cut here---------------start------------->8---
(define* (my-url-fetch url hash-algo hash
                       #:optional name
                       #:key (system (%current-system))
                       (guile (default-guile)))
  (define file-name
    (match url
      ((head _ ...)
       (basename head))
      (_
       (basename url))))

  (let ((uri (and (string? url) (string->uri url))))
    (gexp->derivation name
                      #~(begin
                          (use-modules (web client))

                          (http-get … #:headers …)
                          …)
                      ;; …
                      #:hash hash
                      #:hash-algo hash-algo)))
--8<---------------cut here---------------end--------------->8---

HTH!

Ludo’.