Html/template still escaping template.URL in <a href>?

[blangenfeld]

I’m trying to render a template.URL in an <a href> context, but it always comes out with &s instead of ampersands. What am I missing?

Playground here

package main

import (
	"html/template"
	"os"
)

func main() {
	template.Must(template.New("Template").Parse(`
		Want:
			<a href="http://www.google.com?foo=bar&baz=qux">foo</a>
			
		Got:
			<a href="{{ . }}">foo</a>
	`)).Execute(os.Stdout, template.URL("http://www.google.com?foo=bar&baz=qux"))
}

Output:

		Want:
			<a href="http://www.google.com?foo=bar&baz=qux">foo</a>
			
		Got:
			<a href="http://www.google.com?foo=bar&amp;baz=qux">foo</a>

[radovskyb (Benjamin Radovsky)]

Hey @blangenfeld,

&'s being escaped to & is actually correct encoding.

Here’s a quick example based on your code to show you that the link actually gets rendered correctly (go to http://localhost:9000):

package main

import (
	"html/template"
	"log"
	"net/http"
)

var tmpl = template.Must(template.New("template").Parse(`
	Want: <a href="http://www.google.com?foo=bar&baz=qux">foo</a>
	<br />
	Got: <a href="{{.}}">foo</a>
`))

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-type", "text/html")

		err := tmpl.Execute(w, template.URL("http://www.google.com?foo=bar&baz=qux"))
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}
	})

	log.Fatal(http.ListenAndServe(":9000", nil))
}

If you actually wanted to write a link to os.Stdout without the & encoding, you could simply pass the whole link tag as html into a template instead of what’s just inside of the quotes:

t := template.Must(template.New("template").Parse(`{{.}}`))
err := t.Execute(os.Stdout, template.HTML(`<a href="http://www.google.com?foo=bar&baz=qux">foo</a>`))
if err != nil {
	log.Fatalln(err)
}

[mathew]

I found a post which goes into the technical details, citing the HTML 4 and 5 standards. Yes, encoding the ampersands is correct.

[joncalhoun]

This is a bit late, but here is a blog post that covers some of the encoding contexts used by Go: http://www.calhoun.io/an-intro-to-templates-in-go-part-1-of-3/

I find that it helps to have a broad overview of what Go encodes and when to expect it to avoid issues like this.