Re: Mysterious gzipped images

[Stefan Monnier <monnier@iro.umontreal.ca>]

> [larsi@stories /tmp]$ curl -O https://icons.duckduckgo.com/i/a-z-animals.com.ico
> [larsi@stories /tmp]$ file a-z-animals.com.ico 
> a-z-animals.com.ico: gzip compressed data, max compression
[...]
> So it's a gzipped image!  After unzipping Emacs understands it
> perfectly.

So curl doesn't implement Accept/Content-Encoding either?  That's weird!

>> I think it would be useful to have built-in libz support in Emacs.  When
>> fetching lots of small image files (which is quite common), I think that
>> calling inflate() would be a lot faster than calling the gunzip command
>> over pipes.  Probably.  Should I go ahead and implement this?
> Erm, I went ahead and implemented it.  Should I just check in?  :-)

Sounds good, tho I'd prefer to see the patch first.


        Stefan "Wondering if that could be used to decompress the index
                at the end of PDF files as well"


PS: Here's my previous hack for URL.


=== modified file 'lisp/url/url-http.el'
--- lisp/url/url-http.el	2013-07-22 04:06:21 +0000
+++ lisp/url/url-http.el	2013-07-22 15:45:14 +0000
@@ -313,10 +313,8 @@
              (if url-personal-mail-address
                  (concat
                   "From: " url-personal-mail-address "\r\n"))
-             ;; Encodings we understand
-             (if url-mime-encoding-string
-                 (concat
-                  "Accept-encoding: " url-mime-encoding-string "\r\n"))
+             ;; Encodings we understand.  FIXME: Only use gzip if installed.
+             "Accept-encoding: gzip\r\n"
              (if url-mime-charset-string
                  (concat
                   "Accept-charset: " url-mime-charset-string "\r\n"))
@@ -544,7 +542,16 @@
 	  ;; mark it as successful.
 	  (widen)
 	  (if (and url-automatic-caching (equal url-http-method "GET"))
-	      (url-store-in-cache buffer))))
+	      (url-store-in-cache buffer))
+          ;; Decompress, if needed.  Do it after storing the result in
+          ;; the cache, so the cache keeps the compressed data.
+          (when (mail-fetch-field "Content-Encoding")
+            ;; The only encoding we support.
+            (cl-assert (equal "gzip" (mail-fetch-field "Content-Encoding")))
+            (save-excursion
+              (goto-char (point-min))
+              (re-search-forward "^\n")
+              (call-process-region (point) (point-max) "gzip" t t nil "-d")))))
        (setq success t))
       (3				; Redirection
        ;; 300 Multiple choices