HTTP/2 Server Push

Learn how to implement HTTP/2 Server Push in Iris.

Basic Server Push

package main

import "github.com/kataras/iris/v12"

func main() {
    app := iris.New()

    app.Get("/", func(ctx iris.Context) {
        if pusher := ctx.ResponseWriter().Pusher(); pusher != nil {
            // Push CSS file
            if err := pusher.Push("/assets/style.css", nil); err != nil {
                ctx.Application().Logger().Warnf("Failed to push: %v", err)
            }
            
            // Push JavaScript file
            if err := pusher.Push("/assets/app.js", nil); err != nil {
                ctx.Application().Logger().Warnf("Failed to push: %v", err)
            }
        }

        ctx.View("index.html")
    })

    app.Listen(":8080", iris.WithOptimizations)
}

Advanced Push Options

app.Get("/", func(ctx iris.Context) {
    if pusher := ctx.ResponseWriter().Pusher(); pusher != nil {
        opts := &http.PushOptions{
            Header: http.Header{
                "Accept-Encoding": ctx.Request().Header["Accept-Encoding"],
            },
            Method: "GET",
        }

        assets := []string{
            "/assets/css/style.css",
            "/assets/js/app.js",
            "/assets/images/logo.png",
        }

        for _, asset := range assets {
            if err := pusher.Push(asset, opts); err != nil {
                ctx.Application().Logger().Warnf("Failed to push %s: %v", asset, err)
            }
        }
    }

    ctx.View("index.html")
})

Conditional Push

app.Get("/", func(ctx iris.Context) {
    if !ctx.ClientSupportsHTTP2() {
        ctx.View("index.html")
        return
    }

    if pusher := ctx.ResponseWriter().Pusher(); pusher != nil {
        // Push critical resources first
        criticalAssets := []string{
            "/assets/css/critical.css",
            "/assets/js/critical.js",
        }

        for _, asset := range criticalAssets {
            if err := pusher.Push(asset, nil); err != nil {
                ctx.Application().Logger().Warnf("Failed to push %s: %v", asset, err)
            }
        }

        // Push non-critical resources
        go func() {
            nonCriticalAssets := []string{
                "/assets/css/non-critical.css",
                "/assets/js/non-critical.js",
            }

            for _, asset := range nonCriticalAssets {
                if err := pusher.Push(asset, nil); err != nil {
                    ctx.Application().Logger().Warnf("Failed to push %s: %v", asset, err)
                }
            }
        }()
    }

    ctx.View("index.html")
})

Best Practices

1. Implementation:

   • Push critical resources
   • Check client support
   • Handle errors
   • Monitor pushes
   • Clean resources

2. Performance:

   • Push selectively
   • Prioritize resources
   • Monitor impact
   • Handle timeouts
   • Regular cleanup

3. Headers:

   • Set proper headers
   • Handle encoding
   • Configure caching
   • Monitor support
   • Handle errors

4. Maintenance:

   • Monitor usage
   • Update resources
   • Regular testing
   • Document changes
   • Review performance