Fix channel membership prefixes in cached WHO replies v1 SUPERSEDED

Gregory Anders: 1
 Fix channel membership prefixes in cached WHO replies

 3 files changed, 21 insertions(+), 2 deletions(-)

[PATCH] Fix channel membership prefixes in cached WHO replies Export this patch

Channel membership prefixes in WHO replies (RPL_WHOREPLY and
RPL_WHOSPCRPL) were cached in the user's flags, which meant those same
prefixes were returned on future cache hits, even though the flags are
channel specific.

Strip the channel membership prefixes from the user's flags before
adding a user to the cache and add the prefixes back when reading from
the cache (using the membership info from the NAMES reply).
---
 downstream.go |  5 +++++
 irc.go        | 13 +++++++++++++
 upstream.go   |  5 +++--
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/downstream.go b/downstream.go
index f48653e..0853142 100644
--- a/downstream.go
+++ b/downstream.go
@@ -2230,6 +2230,11 @@ func (dc *downstreamConn) handleMessageRegistered(ctx context.Context, msg *irc.
 				}
 				if uc.isChannel(mask) {
 					info.Channel = mask
+
+					// Set channel membership prefixes from cached NAMES reply
+					ch := uc.channels.Get(info.Channel)
+					memberships := ch.Members.Get(info.Nickname)
+					info.Flags += formatMemberPrefix(*memberships, dc)

Simon Ser <contact@emersion.fr>

8 months ago

I think the ordering of the flags isn't quite right here. IRC is a bit
cumbersome here: the channel membership prefix appears in-between the away/op
status and the other server-specific flags [1]. In other words, with the flags
"H*asdf" and the membership prefix "@+", we need to send "H*@+asdf".
strings.IndexFunc might come in handy here to find the index of the first
character other than "H", "G" or "*".

[1]: https://modern.ircdocs.horse/#rplwhoreply-352

 				}
 				dc.SendMessage(ctx, xirc.GenerateWHOXReply(fields, &info))
 			}
diff --git a/irc.go b/irc.go
index 12732c4..9a7735b 100644
--- a/irc.go
+++ b/irc.go
@@ -194,6 +194,19 @@ func formatMemberPrefix(ms xirc.MembershipSet, dc *downstreamConn) string {
 	return string(prefixes)
 }
 
+// Remove channel membership prefixes from flags
+func stripMemberPrefixes(flags string, uc *upstreamConn) string {
+	return strings.Map(func(r rune) rune {
+		for _, v := range uc.availableMemberships {
+			if byte(r) == v.Prefix {
+				return -1
+			}
+		}
+
+		return r
+	}, flags)
+}
+
 func parseMessageParams(msg *irc.Message, out ...*string) error {
 	if len(msg.Params) < len(out) {
 		return newNeedMoreParamsError(msg.Command)
diff --git a/upstream.go b/upstream.go
index 9173c3a..025646e 100644
--- a/upstream.go
+++ b/upstream.go
@@ -1541,7 +1541,7 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 				Hostname: host,
 				Server:   server,
 				Nickname: nick,
-				Flags:    flags,
+				Flags:    stripMemberPrefixes(flags, uc),
 				Realname: realname,
 			})
 		}
@@ -1564,13 +1564,14 @@ func (uc *upstreamConn) handleMessage(ctx context.Context, msg *irc.Message) err
 			if err != nil {
 				return err
 			}
+
 			if uc.shouldCacheUserInfo(info.Nickname) {
 				uc.cacheUserInfo(info.Nickname, &upstreamUser{
 					Nickname: info.Nickname,
 					Username: info.Username,
 					Hostname: info.Hostname,
 					Server:   info.Server,
-					Flags:    info.Flags,
+					Flags:    stripMemberPrefixes(info.Flags, uc),
 					Account:  info.Account,
 					Realname: info.Realname,
 				})
-- 
2.45.2

Simon Ser <contact@emersion.fr>

8 months ago

On Thursday, June 27th, 2024 at 00:12, Gregory Anders <greg@gpanders.com> wrote:

Thanks a lot for the patch! Just one small comment below, looks good to me
otherwise!