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package fasttemplate
import (
"fmt"
"io"
"log"
"net/url"
)
func ExampleTemplate() {
template := "http://{{host}}/?foo={{bar}}{{bar}}&q={{query}}&baz={{baz}}"
t := New(template, "{{", "}}")
// Substitution map.
// Since "baz" tag is missing in the map, it will be substituted
// by an empty string.
m := map[string]interface{}{
"host": "google.com", // string - convenient
"bar": []byte("foobar"), // byte slice - the fastest
// TagFunc - flexible value. TagFunc is called only if the given
// tag exists in the template.
"query": TagFunc(func(w io.Writer, tag string) (int, error) {
return w.Write([]byte(url.QueryEscape(tag + "=world")))
}),
}
s := t.ExecuteString(m)
fmt.Printf("%s", s)
// Output:
// http://google.com/?foo=foobarfoobar&q=query%3Dworld&baz=
}
func ExampleTagFunc() {
template := "foo[baz]bar"
t, err := NewTemplate(template, "[", "]")
if err != nil {
log.Fatalf("unexpected error when parsing template: %s", err)
}
bazSlice := [][]byte{[]byte("123"), []byte("456"), []byte("789")}
m := map[string]interface{}{
// Always wrap the function into TagFunc.
//
// "baz" tag function writes bazSlice contents into w.
"baz": TagFunc(func(w io.Writer, tag string) (int, error) {
var nn int
for _, x := range bazSlice {
n, err := w.Write(x)
if err != nil {
return nn, err
}
nn += n
}
return nn, nil
}),
}
s := t.ExecuteString(m)
fmt.Printf("%s", s)
// Output:
// foo123456789bar
}
func ExampleTemplate_ExecuteFuncString() {
template := "Hello, [user]! You won [prize]!!! [foobar]"
t, err := 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"]
}
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