Simple and fast template engine for Go.
Fasttemplate performs only a single task - it substitutes template placeholders with user-defined values. At high speed :)
Take a look at quicktemplate if you need fast yet powerful html template engine.
Please note that fasttemplate doesn't do any escaping on template values unlike html/template do. So values must be properly escaped before passing them to fasttemplate.
Fasttemplate is faster than text/template, strings.Replace, strings.Replacer and fmt.Fprintf on placeholders' substitution.
Below are benchmark results comparing fasttemplate performance to text/template, strings.Replace, strings.Replacer and fmt.Fprintf:
$ go test -bench=. -benchmem
PASS
BenchmarkFmtFprintf-4 2000000 790 ns/op 0 B/op 0 allocs/op
BenchmarkStringsReplace-4 500000 3474 ns/op 2112 B/op 14 allocs/op
BenchmarkStringsReplacer-4 500000 2657 ns/op 2256 B/op 23 allocs/op
BenchmarkTextTemplate-4 500000 3333 ns/op 336 B/op 19 allocs/op
BenchmarkFastTemplateExecuteFunc-4 5000000 349 ns/op 0 B/op 0 allocs/op
BenchmarkFastTemplateExecute-4 3000000 383 ns/op 0 B/op 0 allocs/op
BenchmarkFastTemplateExecuteFuncString-4 3000000 549 ns/op 144 B/op 1 allocs/op
BenchmarkFastTemplateExecuteString-4 3000000 572 ns/op 144 B/op 1 allocs/op
BenchmarkFastTemplateExecuteTagFunc-4 2000000 743 ns/op 144 B/op 3 allocs/op
See http://godoc.org/github.com/valyala/fasttemplate .
template := "http://{{host}}/?q={{query}}&foo={{bar}}{{bar}}"
t := fasttemplate.New(template, "{{", "}}")
s := t.ExecuteString(map[string]interface{}{
"host": "google.com",
"query": url.QueryEscape("hello=world"),
"bar": "foobar",
})
fmt.Printf("%s", s)
// Output:
// http://google.com/?q=hello%3Dworld&foo=foobarfoobar template := "Hello, [user]! You won [prize]!!! [foobar]"
t, err := fasttemplate.NewTemplate(template, "[", "]")
if err != nil {
log.Fatalf("unexpected error when parsing template: %s", err)
}
s := t.ExecuteFuncString(func(w io.Writer, tag string) (int, error) {
switch tag {
case "user":
return w.Write([]byte("John"))
case "prize":
return w.Write([]byte("$100500"))
default:
return w.Write([]byte(fmt.Sprintf("[unknown tag %q]", tag)))
}
})
fmt.Printf("%s", s)
// Output:
// Hello, John! You won $100500!!! [unknown tag "foobar"]