fasttemplate

Simple and fast template engine for Go

Programming language: Go

License: MIT License

Tags: Template Engines    

Latest version: v1.1.1

README

fasttemplate

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

Docs

See http://godoc.org/github.com/valyala/fasttemplate .

Usage

    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

Advanced usage

    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"]