bug#17959: support accessing FTP services via HTTP proxies

[Ivan Shmakov]

>>>>> Ivan Shmakov <ivan@siamics.net> writes:

[…]

 > Given that the only thing that EWW has to do to support ftp_proxy is
 > to ensure the user configuration specifies an HTTP proxy to use for
 > the target ftp: URI, it just seems like to simple a feature to omit
 > it.

        The patch MIMEd seems to resolve the issue.

 > When no HTTP proxy is specified for the URI, EWW should indeed
 > somehow invoke the Emacs native FTP client instead.

 > I guess the same approach may be applied to the other URI schemes
 > just as well (gopher:, perhaps?)

        FTR, – I’ve tried to access [1] via Squid, and it just worked.

[1] gopher://gopher.docfile.org/1/world/monitoring/uptime

[…]

-- 
FSF associate member #7257  http://boycottsystemd.org/  … 3013 B6A0 230E 334A

--- a/lisp/net/eww.el   2014-12-09 03:21:57 +0000
+++ b/lisp/net/eww.el   2014-12-16 19:59:32 +0000
@@ -252,8 +238,15 @@
   (setq url (string-trim url))
   (cond ((string-match-p "\\`file:/" url))
        ;; Don't mangle file: URLs at all.
-        ((string-match-p "\\`ftp://"; url)
-         (user-error "FTP is not supported."))
+       ((let* ((parsed (url-generic-parse-url url))
+               (loader (url-scheme-get-property (url-type parsed) 'loader))
+               (proxy  (and (url-host parsed)
+                            (url-find-proxy-for-url
+                             parsed (url-host parsed)))))
+          (and (eq 'url-ftp loader)
+               (or (not proxy)
+                   (not (string-match-p "^https?://" proxy)))))
+        (user-error "Direct FTP is not supported."))
         (t
          (if (and (= (length (split-string url)) 1)
                  (or (and (not (string-match-p "\\`[\"\'].*[\"\']\\'" url))