bug#44906: Substitute requests fail if URL has trailing slash

[zimoun <zimon.toutoune@gmail.com>]

Dear,

Thank you for the report.


Tweaking the function such as:

--8<---------------cut here---------------start------------->8---
(define (narinfo-request cache-url path)
  "Return an HTTP request for the narinfo of PATH at CACHE-URL."
  (let ((url (string-append cache-url "/" (store-path-hash-part path)
                            ".narinfo"))
        (headers '((User-Agent . "GNU Guile"))))
    (format #t "~%Narinfo request: ~a~%~%" url)
    (build-request (string->uri url) #:method 'GET #:headers headers)))
--8<---------------cut here---------------end--------------->8---

and removing the cache adequately, then running:

--8<---------------cut here---------------start------------->8---
./pre-inst-env guix weather \
     --substitute-urls="https://ci.guix.gnu.org/ https://ci.guix.gnu.org" \
     hello
computing 1 package derivations for x86_64-linux...

looking for 1 store items on https://ci.guix.gnu.org/...

Narinfo request: https://ci.guix.gnu.org//a462kby1q51ndvxdv3b6p0rsixxrgx1h.narinfo

updating substitutes from 'https://ci.guix.gnu.org/'... 100.0%
https://ci.guix.gnu.org/
  0.0% substitutes available (0 out of 1)

[...]

  'https://ci.guix.gnu.org//api/queue?nr=1000' returned 400 ("Bad Request")

looking for 1 store items on https://ci.guix.gnu.org...

Narinfo request: https://ci.guix.gnu.org/a462kby1q51ndvxdv3b6p0rsixxrgx1h.narinfo

updating substitutes from 'https://ci.guix.gnu.org'... 100.0%
https://ci.guix.gnu.org
  100.0% substitutes available (1 out of 1)

[...]

  at least 1,000 queued builds

[...]

  build rate: 36.89 builds per hour

[...]
--8<---------------cut here---------------end--------------->8---


On Fri, 27 Nov 2020 at 22:19, Hartmut Goebel <h.goebel@crazy-compilers.com> wrote:

> According to RFC 7230, sec 2.7.3 "http and https URI Normalization and
> Comparison" [1]:
>
>    […] an empty
>    path component is equivalent to an absolute path of "/", so the
>    normal form is to provide a path of "/" instead.
>
> [1] https://tools.ietf.org/html/rfc7230#section-2.7.3

Now, the question is where should the fix go?  “guix publish” exposing
the narinfos or “guix weather“?  Or both?


From my understanding, one fix should go to ‘guix publish’ exposing the
narinfos since:

   https://ci.guix.gnu.org//a462kby1q51ndvxdv3b6p0rsixxrgx1h.narinfo

should be a valid URL and return the narinfo file.  However, taking this
road, it means that the cache folder will not be the same:

~/.cache/guix/substitute/x2wcz6gz3evwlqcrz3fqstmezkfcfnpfb5kfyxbz7kjikc7upkiq/
~/.cache/guix/substitute/4refhwxbjmeua2kwg2nmzhv4dg4d3dorpjefq7kiciw2pfhaf26a/

https://ci.guix.gnu.org/ resp. https://ci.guix.gnu.org  Therefore, ‘guix
weather’ should be fixed too.


WDYT?

All the best,
simon