From da4bc3cb057f5a382571cbc0b554107b8f644d53 Mon Sep 17 00:00:00 2001
From: schmidtw <Weston_Schmidt@alumni.purdue.edu>
Date: Mon, 18 Dec 2023 23:27:56 -0800
Subject: [PATCH] Provide a simple callback function for when you need to know
 a ping came in.  This should address #246.

---
 conn.go | 9 +++++++++
 read.go | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/conn.go b/conn.go
index ef4d62ad..f57cec27 100644
--- a/conn.go
+++ b/conn.go
@@ -79,6 +79,8 @@ type Conn struct {
 	pingCounter   int32
 	activePingsMu sync.Mutex
 	activePings   map[string]chan<- struct{}
+
+	pingCallback func()
 }
 
 type connConfig struct {
@@ -251,6 +253,13 @@ func (c *Conn) ping(ctx context.Context, p string) error {
 	}
 }
 
+// SetPingCallback sets a callback that is called when a ping is received.
+// The callback is called synchronously from the Reader goroutine and must
+// not block.
+func (c *Conn) SetPingCallback(cb func()) {
+	c.pingCallback = cb
+}
+
 type mu struct {
 	c  *Conn
 	ch chan struct{}
diff --git a/read.go b/read.go
index 8742842e..8f25b338 100644
--- a/read.go
+++ b/read.go
@@ -294,6 +294,9 @@ func (c *Conn) handleControl(ctx context.Context, h header) (err error) {
 
 	switch h.opcode {
 	case opPing:
+		if c.pingCallback != nil {
+			c.pingCallback()
+		}
 		return c.writeControl(ctx, opPong, b)
 	case opPong:
 		c.activePingsMu.Lock()