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"]