Add support for deleting messages across bridges.

Currently fully support mattermost,slack and discord.
Message deleted on the bridge or received from other bridges will be
deleted.

Partially support for Gitter.
Gitter bridge will delete messages received from other bridges.
But if you delete a message on gitter, this deletion will not be sent to
other bridges (this is a gitter API limitation, it doesn't propogate edits
or deletes via the API)

1 files changed, 11 insertions, 0 deletions

diff --git a/bridge/gitter/gitter.go b/bridge/gitter/gitter.go
index 9a7b3bf9..b1d68733 100644
--- a/bridge/gitter/gitter.go
+++ b/bridge/gitter/gitter.go
@@ -106,6 +106,17 @@ func (b *Bgitter) Send(msg config.Message) (string, error) {
 		flog.Errorf("Could not find roomID for %v", msg.Channel)
 		return "", nil
 	}
+	if msg.Event == config.EVENT_MSG_DELETE {
+		if msg.ID == "" {
+			return "", nil
+		}
+		// gitter has no delete message api
+		_, err := b.c.UpdateMessage(roomID, msg.ID, "")
+		if err != nil {
+			return "", err
+		}
+		return "", nil
+	}
 	if msg.ID != "" {
 		flog.Debugf("updating message with id %s", msg.ID)
 		_, err := b.c.UpdateMessage(roomID, msg.ID, msg.Username+msg.Text)