利用浏览器缓存静态文件

Question

I am not sure, how in Golang we can leverage browser caching for only static files like CSS, js and not HTML template file.

With .htaccess in Apache, it used to be easy, but I don't see any such thing in golang

I want to know, any hack or method available where I can cache static files like css, js

without using cloudflare - My app does not work with cloudflare.

Answer 1

Browser caching is controlled by headers sent by the server. This way it doesn’t depend on particular installed software.

You need to send headers Etag and Cache-Control. Like this

func Handler(w http.ResponseWriter, r *http.Request) {
    e := "SomeKey describing content - eg checksum"
    w.Header().Set("Etag", e)
    w.Header().Set("Cache-Control", "max-age=2592000") // 30 days

    if match := r.Header.Get("If-None-Match"); match != "" {
        if strings.Contains(match, e) {
            w.WriteHeader(http.StatusNotModified)
            return
        }
    }
    ...
}

Useful links:

• More details https://www.sanarias.com/blog/115LearningHTTPcachinginGo

• Middleware example https://github.com/dc0d/cache-control by Kaveh Shahbazian

• Intro to HTTP caching and headers http://dev.mobify.com/blog/beginners-guide-to-http-cache-headers/