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transform/livereloadinject: Inject livereload script right after head…

… if possible

We used to insert the livereload script right before the closing body.

This dord  not work when combined with tools such as Turbolinks.

This commit changes it So we try to inject the script as early as possible.

Fixes #6821
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bep committed Jan 29, 2020
1 parent 281abb1 commit 8f08cdd0ac6a2decd5aa5c9c12c0b2c264f9a989
Showing with 71 additions and 24 deletions.
  1. +41 −12 transform/livereloadinject/livereloadinject.go
  2. +30 −12 transform/livereloadinject/livereloadinject_test.go
@@ -21,25 +21,54 @@ import (
"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()
endBodyTag := "</body>"
match := []byte(endBodyTag)
replaceTemplate := `<script data-no-instant>document.write('<script src="/livereload.js?port=%d&mindelay=10&v=2"></' + 'script>')</script>%s`
replace := []byte(fmt.Sprintf(replaceTemplate, port, endBodyTag))

newcontent := bytes.Replace(b, match, replace, 1)
if len(newcontent) == len(b) {
endBodyTag = "</BODY>"
replace := []byte(fmt.Sprintf(replaceTemplate, port, endBodyTag))
match := []byte(endBodyTag)
newcontent = bytes.Replace(b, match, replace, 1)
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
}
}

if _, err := ft.To().Write(newcontent); err != nil {
c := make([]byte, len(b))
copy(c, b)

if idx == -1 {
_, err := ft.To().Write(c)
return err
}

script := []byte(fmt.Sprintf(`<script data-no-instant>document.write('<script src="/livereload.js?port=%d&mindelay=10&v=2"></' + 'script>')</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
@@ -15,27 +15,45 @@ package livereloadinject

import (
"bytes"
"fmt"
"strings"
"testing"

qt "github.com/frankban/quicktest"
"github.com/gohugoio/hugo/transform"
)

func TestLiveReloadInject(t *testing.T) {
doTestLiveReloadInject(t, "</body>")
doTestLiveReloadInject(t, "</BODY>")
}
c := qt.New(t)

func doTestLiveReloadInject(t *testing.T, bodyEndTag string) {
out := new(bytes.Buffer)
in := strings.NewReader(bodyEndTag)
expectBase := `<script data-no-instant>document.write('<script src="/livereload.js?port=1313&mindelay=10&v=2"></' + 'script>')</script>`
apply := func(s string) string {
out := new(bytes.Buffer)
in := strings.NewReader(s)

tr := transform.New(New(1313))
tr.Apply(out, in)
tr := transform.New(New(1313))
tr.Apply(out, in)

expected := fmt.Sprintf(`<script data-no-instant>document.write('<script src="/livereload.js?port=1313&mindelay=10&v=2"></' + 'script>')</script>%s`, bodyEndTag)
if out.String() != expected {
t.Errorf("Expected %s got %s", expected, out.String())
return out.String()
}

c.Run("Head lower", func(c *qt.C) {
c.Assert(apply("<html><head>foo"), qt.Equals, "<html><head>"+expectBase+"foo")
})

c.Run("Head upper", func(c *qt.C) {
c.Assert(apply("<html><HEAD>foo"), qt.Equals, "<html><HEAD>"+expectBase+"foo")
})

c.Run("Body lower", func(c *qt.C) {
c.Assert(apply("foo</body>"), qt.Equals, "foo"+expectBase+"</body>")
})

c.Run("Body upper", func(c *qt.C) {
c.Assert(apply("foo</BODY>"), qt.Equals, "foo"+expectBase+"</BODY>")
})

c.Run("No match", func(c *qt.C) {
c.Assert(apply("<h1>No match</h1>"), qt.Equals, "<h1>No match</h1>")
})

}

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