Function TestProxyWebSocketXForwardedFor

middleware/proxy_test.go:1176–1272

TestProxyWebSocketXForwardedFor verifies that for WebSocket Upgrade requests, the proxy middleware appends c.RealIP() to any existing X-Forwarded-For chain, mirroring net/http/httputil.(*ProxyRequest).SetXForwarded used by the HTTP path. Regression guard for the previous "set only if empty" behavio

(t *testing.T)

// the proxy's own peer IP from the chain whenever upstream proxies had already
// added entries.
func TestProxyWebSocketXForwardedFor(t *testing.T) {
	tests := []struct {
		name        string
		incomingXFF []string // nil = no incoming X-Forwarded-For header at all
		wantPrefix  string   // expected join of entries preceding the appended proxy RealIP
	}{
		{
			name:        "no incoming XFF, only proxy RealIP is set",
			incomingXFF: nil,
			wantPrefix:  "",
		},
		{
			name:        "single-line single-entry XFF is preserved with proxy RealIP appended",
			incomingXFF: []string{"203.0.113.1"},
			wantPrefix:  "203.0.113.1",
		},
		{
			name:        "single-line comma-separated XFF is preserved with proxy RealIP appended",
			incomingXFF: []string{"203.0.113.1, 10.0.0.5"},
			wantPrefix:  "203.0.113.1, 10.0.0.5",
		},
		{
			name:        "multi-line XFF (multiple header occurrences) is joined with proxy RealIP appended",
			incomingXFF: []string{"203.0.113.1", "10.0.0.5"},
			wantPrefix:  "203.0.113.1, 10.0.0.5",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// Buffered so the upstream handler never blocks before the client reads.
			headerCh := make(chan http.Header, 1)

			upstream := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				wsHandler := func(conn *websocket.Conn) {
					headerCh <- conn.Request().Header.Clone()
					defer conn.Close()
					var msg string
					if err := websocket.Message.Receive(conn, &msg); err == nil {
						_ = websocket.Message.Send(conn, msg)
					}
				}
				websocket.Server{Handler: wsHandler}.ServeHTTP(w, r)
			}))
			defer upstream.Close()

			tgtURL, _ := url.Parse(upstream.URL)
			e := echo.New()
			e.Use(ProxyWithConfig(ProxyConfig{Balancer: NewRandomBalancer([]*ProxyTarget{{URL: tgtURL}})}))
			proxySrv := httptest.NewServer(e)
			defer proxySrv.Close()

			proxyWSURL, _ := url.Parse(proxySrv.URL)
			proxyWSURL.Scheme = "ws"

			origin, _ := url.Parse(proxySrv.URL)
			cfg := &websocket.Config{
				Location: proxyWSURL,