ref: c91dbe4ce9c30623ba6e686fd17efae935aa0cc5
dir: /transform/livereloadinject/livereloadinject.go/
// Copyright 2018 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package livereloadinject
import (
"bytes"
"fmt"
"github.com/gohugoio/hugo/helpers"
"github.com/gohugoio/hugo/transform"
)
type tag struct {
markup []byte
appendScript bool
}
var tags = []tag{
tag{markup: []byte("<head>"), appendScript: true},
tag{markup: []byte("<HEAD>"), appendScript: true},
tag{markup: []byte("</body>")},
tag{markup: []byte("</BODY>")},
}
// New creates a function that can be used
// to inject a script tag for the livereload JavaScript in a HTML document.
func New(port int) transform.Transformer {
return func(ft transform.FromTo) error {
b := ft.From().Bytes()
var idx = -1
var match tag
// We used to insert the livereload script right before the closing body.
// This does not work when combined with tools such as Turbolinks.
// So we try to inject the script as early as possible.
for _, t := range tags {
idx = bytes.Index(b, t.markup)
if idx != -1 {
match = t
break
}
}
c := make([]byte, len(b))
copy(c, b)
if idx == -1 {
_, err := ft.To().Write(c)
return err
}
script := []byte(fmt.Sprintf(`<script src="/livereload.js?port=%d&mindelay=10&v=2" data-no-instant defer></script>`, port))
i := idx
if match.appendScript {
i += len(match.markup)
}
c = append(c[:i], append(script, c[i:]...)...)
if _, err := ft.To().Write(c); err != nil {
helpers.DistinctWarnLog.Println("Failed to inject LiveReload script:", err)
}
return nil
}
}