[Golang] Access HTTP Request Header by XHR getAllResponseHeaders()
source link: http://siongui.github.io/2016/01/25/go-http-request-header-by-xhr-getAllResponseHeaders/
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Introduction
Access HTTP Request Header in Golang code running on your browser. This can be done by getAllResponseHeaders() method in XMLHttpRequest (XHR) request, as discussed in [4]. According to my test, many important fields such as Accept-Language, however, are missing, which makes this technique useless. I suggest you use another technique [6] to access HTTP request headers.
Install GopherJS and XHR binding
Run the following command to install GopherJS and GopherJS bindings for the XMLHttpRequest API:
$ go get -u github.com/gopherjs/gopherjs $ go get -u honnef.co/go/js/xhr
Source Code
HTML file for demo: (index.html)
<!doctype html>
<html>
<head>
<title>Golang - access HTTP Request Header
by XHR getAllResponseHeaders()</title>
</head>
<body>
<script src="demo.js"></script>
</body>
</html>
The Golang code for retrieving HTTP request headers via getAllResponseHeaders():
getAllResponseHeaders.go | repository | view raw
package main
import "honnef.co/go/js/xhr"
func main() {
req := xhr.NewRequest("GET", "/")
err := req.Send(nil)
if err != nil { println(err) }
headers := req.ResponseHeaders()
println(headers)
}
Compile Go code to JavaScript by:
$ gopherjs build getAllResponseHeaders.go -o demo.js
Put demo.js together with the index.html in the same directory. You need a simple HTTP server to run this demo. Use GopherJS serve command to serve the above files, and open your browser console to see the output. My output is:
Date: Sun, 24 Jan 2016 20:11:53 GMT Last-Modified: Fri, 22 Jan 2016 12:59:37 GMT Accept-Ranges: bytes Content-Length: 145 Content-Type: text/html; charset=utf-8
Appendix
If you want to use GopherJS native API only without XHR binding, you can use the following code:
getAllResponseHeaders-raw.go | repository | view raw
package main
import "github.com/gopherjs/gopherjs/js"
func main() {
req := js.Global.Get("XMLHttpRequest").New()
req.Call("addEventListener", "load", func() {
headers := req.Call("getAllResponseHeaders").String()
println(headers)
})
req.Call("open", "GET", "/", true)
req.Call("send")
}
Tested on: Ubuntu Linux 15.10, Go 1.5.3, Chromium Version 47.0.2526.106 Ubuntu 15.10 (64-bit).
References:
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