Changeset 415 in code for trunk

Timestamp:

Sep 2, 2020, 3:09:32 PM (5 years ago)

Author:

hubert

Message:

Make sure that WebSocket messages are valid UTF-8

... by replacing invalid bytes with the REPLACEMENT CHARACTER U+FFFD

This is better than:

• discarding the whole message, since the user would not see it...
• removing invalid bytes, since the user would not see their presence,
• converting the encoding (this is actually not possible).

Contrary to its documentation, strings.ToValidUTF8 doesn't copy the
string if it's valid UTF-8:
<​https://golang.org/src/strings/strings.go?s=15815:15861#L623>

File:

• trunk/conn.go (modified) (2 diffs)

trunk/conn.go

@@ -6 +6 @@
         "io"
         "net"
+        "strings"
         "sync"
         "time"
+        "unicode"
 
         "gopkg.in/irc.v3"
@@ -63 +65 @@
 
 func (wic websocketIRCConn) WriteMessage(msg *irc.Message) error {
-        b := []byte(msg.String())
+        b := []byte(strings.ToValidUTF8(msg.String(), string(unicode.ReplacementChar)))
         ctx := context.Background()
         if !wic.writeDeadline.IsZero() {