模板和自定义功能;恐慌：功能未定义 [英] Template and custom function; panic: function not defined
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问题描述
使用 html / template 我想在模板中使用我自己的函数之一。不幸的是，我无法使用go模板的功能图功能。我得到的是以下错误：
Using html/template I am trying to use one of my own functions inside a template. Unfortunately I am unable to use the function map feature of go's templates. All I get is the following error:
% go run test.go
panic: template: tmpl.html:5: function "humanSize" not defined
[...]
如下所示（ test.go ）：
The reduced testcase looks as follows (test.go):
package main
import (
"html/template"
"io/ioutil"
"net/http"
"strconv"
)
var funcMap = template.FuncMap{
"humanSize": humanSize,
}
var tmplGet = template.Must(template.ParseFiles("tmpl.html")).Funcs(funcMap)
func humanSize(s int64) string {
return strconv.FormatInt(s/int64(1000), 10) + " KB"
}
func getPageHandler(w http.ResponseWriter, r *http.Request) {
files, _ := ioutil.ReadDir(".")
if err := tmplGet.Execute(w, files); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
func main() {
http.HandleFunc("/", getPageHandler)
http.ListenAndServe(":8080", nil)
}
我有以下简单模板（ tmpl.html ）：
And I have the following simple template (tmpl.html):
<html><body>
{{range .}}
<div>
<span>{{.Name}}</span>
<span>{{humanSize .Size}}</span>
</div>
{{end}}
</body></html>
这是1.1.1。
推荐答案
.Funcs 定义。
IIRC, template functions map must be defined by .Funcs before parsing the template. The below code seems to work.
package main
import (
"html/template"
"io/ioutil"
"net/http"
"strconv"
)
var funcMap = template.FuncMap{
"humanSize": humanSize,
}
const tmpl = `
<html><body>
{{range .}}
<div>
<span>{{.Name}}</span>
<span>{{humanSize .Size}}</span>
</div>
{{end}}
</body></html>`
var tmplGet = template.Must(template.New("").Funcs(funcMap).Parse(tmpl))
func humanSize(s int64) string {
return strconv.FormatInt(s/int64(1000), 10) + " KB"
}
func getPageHandler(w http.ResponseWriter, r *http.Request) {
files, err := ioutil.ReadDir(".")
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
if err := tmplGet.Execute(w, files); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}
func main() {
http.HandleFunc("/", getPageHandler)
http.ListenAndServe(":8080", nil)
}
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