Allow for custom URL handlers in browse-url.

* lisp/net/browse-url.el (browse-url-handlers): New defcustom.
(browse-url): Use it.

1 files changed, 25 insertions, 6 deletions

diff --git a/lisp/net/browse-url.el b/lisp/net/browse-url.el
index 7aad44b2876..ab0be7b913e 100644
--- a/lisp/net/browse-url.el
+++ b/lisp/net/browse-url.el
@@ -175,6 +175,23 @@ Also see `browse-url-secondary-browser-function'."
   :type browse-url--browser-defcustom-type
   :version "24.1")
 
+;;;#autoload
+(defcustom browse-url-handlers
+  `(("\\`mailto:" . ,browse-url-mailto-function)
+    ("\\`man:" . ,browse-url-man-function))
+  "An alist with elements of the form (REGEXP HANDLER).
+Each REGEXP is matched against each URL to be opened in turn and
+the first match's HANDLER is invoked with the URL.
+
+A HANDLER must either be a function with the same arguments as
+`browse-url' or a variable whos value is such a function.
+
+If no REGEXP matches, the bug reference URL is opened using the
+value of `browse-url-browser-function'."
+  :type '(alist :key-type (regexp :tag "Regexp")
+                :value-type (function :tag "Handler"))
+  :version "28.1")
+
 (defcustom browse-url-secondary-browser-function 'browse-url-default-browser
   "Function used to launch an alternative browser.
 This is usually an external browser (that is, not eww or w3m),
@@ -786,12 +803,14 @@ as ARGS."
              (not (string-match "\\`[a-z]+:" url)))
     (setq url (expand-file-name url)))
   (let ((process-environment (copy-sequence process-environment))
-	(function (or (and (string-match "\\`mailto:" url)
-			   browse-url-mailto-function)
-                      (and (string-match "\\`man:" url)
-                           browse-url-man-function)
-		      browse-url-browser-function))
-	;; Ensure that `default-directory' exists and is readable (b#6077).
+	(function
+         (catch 'custom-url-handler
+           (dolist (regex-handler browse-url-handlers)
+             (when (string-match-p (car regex-handler) url)
+               (throw 'custom-url-handler (cdr regex-handler))))
+           ;; No special handler found.
+           browse-url-browser-function))
+	;; Ensure that `default-directory' exists and is readable (bug#6077).
 	(default-directory (or (unhandled-file-name-directory default-directory)
 			       (expand-file-name "~/"))))
     ;; When connected to various displays, be careful to use the display of