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 (

 func main() {
 resp, err := http.Head("http://www.golang.org")

 if err != nil {

 // 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

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.