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 gohugoio#6821
bep · Jan 29, 2020 · d694d02 · d694d02
1 parent d8e6851
commit d694d02
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Showing 2 changed files with 71 additions and 24 deletions.
diff --git a/transform/livereloadinject/livereloadinject.go b/transform/livereloadinject/livereloadinject.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

diff --git a/transform/livereloadinject/livereloadinject_test.go b/transform/livereloadinject/livereloadinject_test.go
@@ -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>")
+	})
+
 }