Go template function | 易学教程

问题

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 ?

回答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.

回答2:

Sonia's answer is technically correct but left me even more confused. Here's how I eventually got it working:

t, err := template.New("_base.html").Funcs(funcs).ParseFiles("../view/_base.html", "../view/home.html")
if err != nil {
    fmt.Fprint(w, "Error:", err)
    fmt.Println("Error:", err)
    return
}
err = t.Execute(w, data)
if err != nil {
    fmt.Fprint(w, "Error:", err)
    fmt.Println("Error:", err)
}

The name of the template is the bare filename of the template, not the complete path. Execute will execute the default template provided it's named to match, so there's no need to use ExecuteTemplate.

In this case, _base.html file is the outermost container, eg:

<!DOCTYPE html>
<html><body>
<h1>{{ template "title" }}</h1>
{{ template "content" }}
</body></html>

while home.html defines the specific parts:

{{ define "title" }}Home{{ end }}

{{ define "content" }}
Stuff
{{ end }}

来源：https://stackoverflow.com/questions/10199219/go-template-function

标签

go-templates