Golang : Get curl -I or head data from URL example
Problem :
Need a way to make a HEAD request from URL and extract a few fields of header data from the response.
Solution :
A HEAD request is similar to curl -I
command and in Golang, the similar task can be achieved with the net/http.Head()
function.
Here is an example of HEAD request in Golang :
package main
import (
"fmt"
"net/http"
)
func main() {
resp, err := http.Head("http://www.golang.org")
if err != nil {
fmt.Println(err)
return
}
fmt.Println(resp)
// you can isolate the data further
// READ http://golang.org/pkg/net/http/#Response
contentLength := resp.ContentLength
fmt.Println("Content Length : ", contentLength)
}
and the output :
&{200 OK 200 HTTP/1.1 1 1 map[Content-Type:[text/html; charset=utf-8] Date:[Mon, 20 Jul 2015 09:02:28 GMT] Server:[Google Frontend]
Content-Length:[7537] Alternate-Protocol:[80:quic,p=0]] 0xc208054500 7537 [] false map[] 0xc208032750
} Content Length : 7537
and compare the output to curl -I
command.
>curl -I https://www.golang.org
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Date: Mon, 20 Jul 2015 08:54:37 GMT
Server: Google Frontend
Content-Length: 7537
Alternate-Protocol: 443:quic,p=1
References :
See also : Golang : Set or Add HTTP Request Headers
By Adam Ng
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