tls-autodetect: mark issues, fix initialization

prototypes/tls-autodetect.go

@@ -16,14 +16,14 @@
 //
 // This is an example TLS-autodetecting chat server.
 //
-// You may connect to it using either of these:
-//  ncat -C localhost 1234
-//  ncat -C --ssl localhost 1234
-//
-// These clients are unable to properly shutdown the connection:
+// These clients are unable to properly shutdown the connection on their exit:
 //  telnet localhost 1234
 //  openssl s_client -connect localhost:1234
 //
+// While this one doesn't react to an EOF from the server:
+//  ncat -C localhost 1234
+//  ncat -C --ssl localhost 1234
+//
 package main
 
 import (
@@ -165,7 +165,7 @@ func forceShutdown(reason string) {
 // --- Client ------------------------------------------------------------------
 
 func (c *client) send(line string) {
-	if !c.closing {
+	if c.conn != nil && !c.closing {
 		c.outQ = append(c.outQ, (line + "\r\n")...)
 		c.flushOutQ()
 	}
@@ -205,6 +205,7 @@ func (c *client) destroy() {
 		c.killTimer.Stop()
 	}
 
+	log.Println("client destroyed")
 	delete(clients, c)
 }
 
@@ -341,6 +342,8 @@ func prepare(client *client) {
 		}
 	}
 
+	// Note that in this demo application the autodetection prevents non-TLS
+	// clients from receiving any messages until they send something.
 	isTLS := false
 	if sysconn, err := conn.(syscall.Conn).SyscallConn(); err != nil {
 		// This is just for the TLS detection and doesn't need to be fatal.
@@ -349,6 +352,7 @@ func prepare(client *client) {
 		isTLS = detectTLS(sysconn)
 	}
 
+	// FIXME: When the client sends no data, we still initialize its conn.
 	prepared <- preparedEvent{client, host, isTLS}
 }