open: allow overriding default program

Instead of xdg-open (or open on MacOS), allow forcing a program to open
a message part. The program is determined in that order of priority:

1) If :open has arguments, they will be used as command to open the
   attachment. If the arguments contain the {} placeholder, the
   temporary file will be substituted, otherwise the file path is added
   at the end of the arguments.

2) If a command is specified in the [openers] section of aerc.conf for
   the part MIME type, then it is used with the same rules of {}
   substitution.

3) Finally, fallback to xdg-open/open with the file path as argument.

Update the docs and default config accordingly with examples.

Fixes: https://todo.sr.ht/~rjarry/aerc/64
Co-authored-by: Jason Stewart <support@eggplantsd.com>
Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Moritz Poldrack <moritz@poldrack.dev>

1 files changed, 14 insertions, 0 deletions

diff --git a/config/aerc.conf b/config/aerc.conf
index 6e5efe7d..0bd96fb5 100644
--- a/config/aerc.conf
+++ b/config/aerc.conf
@@ -308,6 +308,20 @@ text/plain=sed 's/^>\+.*/\x1b[36m&\x1b[0m/'
 #text/html=w3m -dump -I UTF-8 -T text/html
 #image/*=catimg -w $(tput cols) -
 
+[openers]
+#
+# Openers allow you to specify the command to use for the :open action on a
+# per-MIME-type basis.
+#
+# {} is expanded as the temporary filename to be opened. If it is not
+# encountered in the command, the temporary filename will be appened to the end
+# of the command.
+#
+# Examples:
+# text/html=surf -dfgms
+# text/plain=gvim {} +125
+# message/rfc822=thunderbird
+
 [triggers]
 #
 # Triggers specify commands to execute when certain events occur.