feat: add support for server-sent events (#72)

example/example.go

@@ -16,6 +16,15 @@ func main() {
 	r.GET("/ping", func(c *gin.Context) {
 		c.String(http.StatusOK, "pong "+fmt.Sprint(time.Now().Unix()))
 	})
+	r.GET("/stream", func(c *gin.Context) {
+		c.Header("Content-Type", "text/event-stream")
+		c.Header("Connection", "keep-alive")
+		for i := 0; i < 10; i++ {
+			fmt.Fprintf(c.Writer, "id: %d\ndata: tick %d\n\n", i, time.Now().Unix())
+			c.Writer.Flush()
+			time.Sleep(1 * time.Second)
+		}
+	})
 
 	// Listen and Server in 0.0.0.0:8080
 	if err := r.Run(":8080"); err != nil {

gzip.go

@@ -32,6 +32,11 @@ func (g *gzipWriter) Write(data []byte) (int, error) {
 	return g.writer.Write(data)
 }
 
+func (g *gzipWriter) Flush() {
+	_ = g.writer.Flush()
+	g.ResponseWriter.Flush()
+}
+
 // Fix: https://github.com/mholt/caddy/issues/38
 func (g *gzipWriter) WriteHeader(code int) {
 	g.Header().Del("Content-Length")

handler.go

@@ -66,8 +66,7 @@ func (g *gzipHandler) Handle(c *gin.Context) {
 
 func (g *gzipHandler) shouldCompress(req *http.Request) bool {
 	if !strings.Contains(req.Header.Get("Accept-Encoding"), "gzip") ||
-		strings.Contains(req.Header.Get("Connection"), "Upgrade") ||
-		strings.Contains(req.Header.Get("Accept"), "text/event-stream") {
+		strings.Contains(req.Header.Get("Connection"), "Upgrade") {
 		return false
 	}