Serving files from static url with Go / Negroni / Gorilla Mux

Question

So I am new to Go and trying it out to build a simple web server. One part I am having trouble with is that I want to serve static files with dynamic static urls (to enable long caching by the browser). For example, I might have this url:

/static/876dsf5g87s6df5gs876df5g/application.js

But I want to serve the file located at:

/build/application.js

How would I go about this with Go / Negroni / Gorilla Mux?

elithrar elithrar · Accepted Answer · 2015-04-04T06:39:44

Have you already decided on how to record/persist the "random" part of the URL? DB? In memory (i.e. not across restarts)? If not, crypto/sha1 the file(s) on start-up, and store the resultant SHA-1 hash in a map/slice.

Otherwise, a route like (assuming Gorilla) r.Handle("/static/{cache_id}/{filename}", YourFileHandler) would work.

package main

import (
    "log"
    "mime"
    "net/http"
    "path/filepath"

    "github.com/gorilla/mux"
)

func FileServer(w http.ResponseWriter, r *http.Request) {
    vars := mux.Vars(r)
    id := vars["cache_id"]

    // Logging for the example
    log.Println(id)

    // Check if the id is valid, else 404, 301 to the new URL, etc - goes here!
    // (this is where you'd look up the SHA-1 hash)

    // Assuming it's valid
    file := vars["filename"]

    // Logging for the example
    log.Println(file)

    // Super simple. Doesn't set any cache headers, check existence, avoid race conditions, etc.
    w.Header().Set("Content-Type", mime.TypeByExtension(filepath.Ext(file)))
    http.ServeFile(w, r, "/Users/matt/Desktop/"+file)
}

func IndexHandler(w http.ResponseWriter, r *http.Request) {
    w.Write([]byte("Hello!\n"))
}

func main() {

    r := mux.NewRouter()

    r.HandleFunc("/", IndexHandler)
    r.HandleFunc("/static/{cache_id}/{filename}", FileServer)

    log.Fatal(http.ListenAndServe(":4000", r))
}

That should work out of the box, but I can't promise it's production ready. Personally, I just use nginx to serve my static files and benefit from it's file handler cache, solid gzip implementation, etc, etc.

Serving files from static url with Go / Negroni / Gorilla Mux

2 Answers