Question

It noticed a weird thing with Go templates when I try to use Funcs and FuncMap. The following code works as expected:

buffer := bytes.NewBufferString("")

funcMap := template.FuncMap{
    "label": strings.Title,
}

t, _ := template.New("alex").Funcs(funcMap).Parse("{{label \"alex\"}}") 

t.Execute(buffer, "")

return string(buffer.Bytes()) //=> "Alex"

But when I try to put the template in a file, it does not work (Execute() says: "alex" is an incomplete or empty template):

t, _ := template.New("alex").Funcs(funcMap).ParseFiles("template.html") 

With template.html:

{{label \"alex\"}}

Any idea why ? Is this a bug ? Are there simpler ways to use methods/functions in templates ?

Answer 1

ParseFiles could probably use better documentation. A template object can have multiple templates in it and each one has a name. If you look at the implementation of ParseFiles, you see that it uses the filename as the template name inside of the template object. So, name your file the same as the template object, (probably not generally practical) or else use ExecuteTemplate instead of just Execute.