Is there a way to expand shortened URLs in Go [duplicate] - url

Question

So, I'm using the net/http package. I'm GETting a URL that I know for certain is redirecting. It may even redirect a couple of times before landing on the final URL. Redirection is handled automatically behind the scenes.
Is there an easy way to figure out what the final URL was without a hackish workaround that involves setting the CheckRedirect field on a http.Client object?
I guess I should mention that I think I came up with a workaround, but it's kind of hackish, as it involves using a global variable and setting the CheckRedirect field on a custom http.Client.
There's got to be a cleaner way to do it. I'm hoping for something like this:
package main
import (
"fmt"
"log"
"net/http"
)
func main() {
// Try to GET some URL that redirects. Could be 5 or 6 unseen redirections here.
resp, err := http.Get("http://some-server.com/a/url/that/redirects.html")
if err != nil {
log.Fatalf("http.Get => %v", err.Error())
}
// Find out what URL we ended up at
finalURL := magicFunctionThatTellsMeTheFinalURL(resp)
fmt.Printf("The URL you ended up at is: %v", finalURL)
}

Answer 1

package main
import (
"fmt"
"log"
"net/http"
)
func main() {
resp, err := http.Get("http://stackoverflow.com/q/16784419/727643")
if err != nil {
log.Fatalf("http.Get => %v", err.Error())
}
// Your magic function. The Request in the Response is the last URL the
// client tried to access.
finalURL := resp.Request.URL.String()
fmt.Printf("The URL you ended up at is: %v\n", finalURL)
}
Output:
The URL you ended up at is: http://stackoverflow.com/questions/16784419/in-golang-how-to-determine-the-final-url-after-a-series-of-redirects

Answer 2

I would add a note that http.Head method should be enough to retrieve the final URL. Theoretically it should be faster comparing to http.Get as a server is expected to send back just a header:
resp, err := http.Head("http://stackoverflow.com/q/16784419/727643")
...
finalURL := resp.Request.URL.String()
...