Escaping "/" in template

i wanto to pass a string like this "avatars/avatar.png" but when i pass it to the template i get the character escaped.
So i wrote a func that i pass into template:

var tpl *template.Template

func init() {
	tpl = template.Must(template.ParseGlob("1Forum/static/html/*.html"))
	tpl = tpl.Funcs(template.FuncMap{
		"unescape": func(s string) string {
			unescaped, err := url.PathUnescape(s)
			if err != nil {
				return s
			}
			return unescaped
		},
	})
}

{{unescape .User.Avatar}}

But i continue to get "function "unescape" not defined". Isn't unescape defined?

"net/url" is imported.

> Isn't unescape defined?

Technically not. You do define it, but you do so too late. Whether a function is defined or not is checked during parsing, not execution. You have ParseGlob and then you do tpl.Func(...). That's out of order.

Instead do:

func init() {
    tpl = template.Must(template.New("t").Funcs(template.FuncMap{
        "unescape": func(s string) string {
            unescaped, err := url.PathUnescape(s)
            if err != nil {
                return s
            }
            return unescaped
        },
    }).ParseGlob("1Forum/static/html/*.html"))
}

Note that the escaping, which is a security feature, happens depending on what context you are using the data in, and unescape is likely not going to help you "cheat" your way around that because the escaping will be done on the output of unescape, rather than its input.

In other words, when you do {{unescape .}}, the parser may, depending on the context, turn that into {{unescape . | urlescaper}} (the urlescaper is an internal escaping function). To avoid this, when you have a known secure string that you want to use verbatim in the template, you should use a typed string instead of unescape.

See playground example.

For more info on the contexts, escaping, typed strings, etc. read the package's doc, it's all there clearly explained.

The error message "function "unescape" not defined" indicates that the custom function you defined is not accessible in the template context. To make the function available to your template, you need to pass it as a value to the Funcs method when defining your template:

tpl = 
template.Must(template.ParseGlob("1Forum/static/html/*.html"))
tpl = tpl.Funcs(template.FuncMap{
    "unescape": func(s string) string {
        unescaped, err := url.PathUnescape(s)
        if err != nil {
        return s
    }
    return unescaped
},

})

Make sure to pass the tpl value to the Execute method when rendering the template:

err := tpl.Execute(w, data)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}

This should make the unescape function available in your templates and you should be able to use it without encountering the "function "unescape" not defined" error.

I hope this helps.