Re: Howto: Retrieve only URL metadata

[Adam Porter <adam@alphapapa.net>]

> Is there a light-weight means of just retrieving URL metadata given a
> URL using the url package in Emacs?
> 
> Note: I know how to do that using Curl and parsing the output from a
> HEAD method call; am looking for a pure elisp solution

FYI, if you'll forgive the transgression, since plz.el is in ELPA and 
"part of Emacs", here's a simple way to do it:

   (plz-response-headers
    (plz 'head 
"https://lists.gnu.org/archive/html/emacs-devel/2024-03/msg00670.html"
      :as 'response))

   ;; ((date . "Wed, 27 Mar 2024 04:11:27 GMT")
   ;;  (server . "Apache/2.4.29 (Trisquel_GNU/Linux)")
   ;;  (strict-transport-security . "max-age=63072000; 
includeSubDomains; preload")
   ;;  (x-frame-options . "sameorigin")
   ;;  (x-content-type-options . "nosniff")
   ;;  (last-modified . "Wed, 27 Mar 2024 03:44:54 GMT")
   ;;  (etag . "\"1472-6149c3ac97980-gzip\"")
   ;;  (accept-ranges . "bytes")
   ;;  (vary . "Accept-Encoding")
   ;;  (content-encoding . "gzip")
   ;;  (content-length . "2022")
   ;;  (content-type . "text/html"))

A future version will probably simplify that, returning the alist of 
headers directly for calling:

   (plz 'head URL)