Hands-On System Programming with Go

HTTP/2 Pusher

We have already discussed that Golang supports the HTTP/2 server side push functionality since version 1.8. Let's see how to use it in an application. Its usage is pretty simple; if the request can be casted to the http.Pusher interface, it can be used to push additional requests in the main interface. In this example, we use it to sideload a SVG image, together with the page:

func main() {    const imgPath = "/image.svg"    http.HandleFunc("/", func(w http.ResponseWriter, r         *http.Request) {            pusher, ok := w.(http.Pusher)            if ok {                fmt.Println("Push /image")                pusher.Push(imgPath, nil)            }        w.Header().Add("Content-Type", "text/html")        fmt.Fprintf(w, `<html><body><img src="%s"/>`+            `</body></html>`, imgPath)    }) http.HandleFunc(imgPath, func(w ...