Go Golang to serve a specific html file

Question

http.Handle("/", http.FileServer(http.Dir("static")))

Serves the html file in static directory.

Is there any way in Go that we can specify the html file to serve?

Something like render_template in Flask

I want to do something like:

http.Handle("/hello", http.FileServer(http.Dir("static/hello.html")))

Answer 1

Maybe using a custom http.HandlerFunc would be easier:

Except in your case, your func would be the http.ServeFile one, for serving just one file.

See for instance " Go Web Applications: Serving Static Files ":

Add the following below your home handler(see below):

http.HandleFunc("/static/", func(w http.ResponseWriter, r *http.Request) {
   // do NOT do this. (see below)
    http.ServeFile(w, r, r.URL.Path[1:])
})

This is using the net/http package's ServeFile function to serve our content.
Effectively anything that makes a request starting with the /static/ path will be handled by this function.
One thing I found I had to do in order for the request to be handled correctly was trim the leading '/' using:

r.URL.Path[1:]

Actually, do not do that.
This won't be possible in Go 1.6, as sztanpet comments , with commit 9b67a5d :

If the provided file or directory name is a relative path, it is interpreted relative to the current directory and may ascend to parent directories .
If the provided name is constructed from user input, it should be sanitized before calling ServeFile .
As a precaution, ServeFile will reject requests where r.URL.Path contains a " .. " path element.

That will protect against the following "url":

/../file
/..
/../
/../foo
/..\\foo
/file/a
/file/a..
/file/a/..
/file/a\\..

Answer 2

You could use http.StripPrefix

Like this:

http.Handle("/hello/", http.StripPrefix("/hello/",http.FileServer(http.Dir("static"))))

Answer 3

Maybe I missed something here, but after a lot of confused searching, I put this together:

...

func downloadHandler(w http.ResponseWriter, r *http.Request) {
        r.ParseForm()
        StoredAs := r.Form.Get("StoredAs") // file name
        data, err := ioutil.ReadFile("files/"+StoredAs)
        if err != nil { fmt.Fprint(w, err) }
        http.ServeContent(w, r, StoredAs, time.Now(),   bytes.NewReader(data))
}

...

Where downloadHandler is invoked as part of a simple upload and download server:

func main() {
              http.HandleFunc("/upload", uploadHandler)
              http.HandleFunc("/download", downloadHandler)
              http.ListenAndServe(":3001", nil)
}   

Works fine with Firefox and Chrome. Doesn't even need a file type.