How do you serve a static html file using a go web

问题:

How do you serve index.html (or some other static HTML file) using a go web server?

I just want a basic, static HTML file (like an article, for example) which I can serve from a go web server. The HTML should be modifiable outside of the go program, as it would be in the case while using HTML templates.

This is my web server which only hosts hard-coded text ("Hello world!").

package main

import (
  "fmt"
  "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
  fmt.Fprintf(w, "Hello world!")
}

func main() {
  http.HandleFunc("/", handler)
  http.ListenAndServe(":3000", nil)
}

回答1:

That task is very easy with Golang net/http package.

All You need to do is:

package main

import (
        "net/http"
)

func main() {
        http.Handle("/", http.FileServer(http.Dir("./static")))
        http.ListenAndServe(":3000", nil)
}

assuming that static files are in folder named static in the root directory of the project.

If it's in folder static, you'll have index.html file calling http://localhost:3000/ which will result in rendering that index file instead of listing all the files availible.

Additionally, calling any other file in that folder (for example http://localhost:3000/clients.html) will show that file, properly rendered by the browser (at least Chrome, Firefox and Safari :))

UPDATE: serving files from url different than "/"

If You want to serve files, say from folder ./public under url: localhost:3000/static You have to use additional function: func StripPrefix(prefix string, h Handler) Handler like this:

package main

import (
        "net/http"
)

func main() {
        http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("./public"))))
        http.ListenAndServe(":3000", nil)
}

Thanks to that, all your files from ./public are avalible under localhost:3000/static

Without http.StripPrefix function, if you would try to access file localhost:3000/static/test.html, the server would look for it in ./public/static/test.html

This is because the server treats the whole URI as a relative path to the file.

Fortunately, it's easily solved with the built-in function.

回答2:

NOT a FTP server: That is something different than what I intended, which would be to serve the index.html homepage, like a normal web server would. Like, when I go to mydomain.com in my browser, I want index.html rendered.

That is mainly what "Writing Web Applications" describes, and what a project like hugo (static html site generator) does.

It is about reading a file, and responsing with a ContentType "text/html":

func (server *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    err := server.renderFile(w, r.URL.Path)
    if err != nil {
        w.Header().Set("Content-Type", "text/html; charset=utf-8")
        w.WriteHeader(http.StatusNotFound)
        server.fn404(w, r)
    }
}

with renderFile() essentially reading and setting the right type:

 file, err = ioutil.ReadFile(server.MediaPath + filename)
 if ext != "" {
    w.Header().Set("Content-Type", mime.TypeByExtension(ext))
 }