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livereloadinject: Use more robust injection method
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@DominoPivot @bep
DominoPivot authored and bep committed Oct 29, 2023
1 parent a349aaf commit 9dc6080
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Showing 2 changed files with 80 additions and 61 deletions.
65 changes: 18 additions & 47 deletions transform/livereloadinject/livereloadinject.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,53 +14,38 @@
package livereloadinject

import (
"bytes"
"fmt"
"html"
"net/url"
"regexp"
"strings"

"github.com/gohugoio/hugo/common/loggers"

"github.com/gohugoio/hugo/transform"
)

const warnMessage = `"head" or "body" tag is required in html to append livereload script. ` +
"As a fallback, Hugo injects it somewhere but it might not work properly."

var warnScript = fmt.Sprintf(`<script data-no-instant defer>console.warn('%s');</script>`, warnMessage)

type tag struct {
markup []byte
appendScript bool
warnRequired bool
}

var tags = []tag{
{markup: []byte("<head"), appendScript: true},
{markup: []byte("<HEAD"), appendScript: true},
{markup: []byte("</body>")},
{markup: []byte("</BODY>")},
{markup: []byte("<html"), appendScript: true, warnRequired: true},
{markup: []byte("<HTML"), appendScript: true, warnRequired: true},
var ignoredSyntax = regexp.MustCompile(`(?s)^(?:\s+|<!--.*?-->|<\?.*?\?>)*`)
var tagsBeforeHead = []*regexp.Regexp{
regexp.MustCompile(`(?is)^<!doctype\s[^>]*>`),
regexp.MustCompile(`(?is)^<html(?:\s[^>]*)?>`),
regexp.MustCompile(`(?is)^<head(?:\s[^>]*)?>`),
}

// New creates a function that can be used
// to inject a script tag for the livereload JavaScript in a HTML document.
// New creates a function that can be used to inject a script tag for
// the livereload JavaScript at the start of an HTML document's head.
func New(baseURL url.URL) transform.Transformer {
return func(ft transform.FromTo) error {
b := ft.From().Bytes()
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
}

// We find the start of the head by reading past (in order)
// the doctype declaration, HTML start tag and head start tag,
// all of which are optional, and any whitespace, comments, or
// XML instructions in-between.
idx := 0
for _, tag := range tagsBeforeHead {
idx += len(ignoredSyntax.Find(b[idx:]))
idx += len(tag.Find(b[idx:]))
}

path := strings.TrimSuffix(baseURL.Path, "/")
Expand All @@ -72,23 +57,9 @@ func New(baseURL url.URL) transform.Transformer {
c := make([]byte, len(b))
copy(c, b)

if idx == -1 {
idx = len(b)
match = tag{warnRequired: true}
}

script := []byte(fmt.Sprintf(`<script src="%s" data-no-instant defer></script>`, html.EscapeString(src)))

i := idx
if match.appendScript {
i += bytes.Index(b[i:], []byte(">")) + 1
}

if match.warnRequired {
script = append(script, []byte(warnScript)...)
}

c = append(c[:i], append(script, c[i:]...)...)
c = append(c[:idx], append(script, c[idx:]...)...)

if _, err := ft.To().Write(c); err != nil {
loggers.Log().Warnf("Failed to inject LiveReload script:", err)
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76 changes: 62 additions & 14 deletions transform/livereloadinject/livereloadinject_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,32 +43,80 @@ func TestLiveReloadInject(t *testing.T) {
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("Inject after head tag", func(c *qt.C) {
c.Assert(apply("<!doctype html><html><head>after"), qt.Equals, "<!doctype html><html><head>"+expectBase+"after")
})

c.Run("Head upper", func(c *qt.C) {
c.Assert(apply("<html><HEAD>foo"), qt.Equals, "<html><HEAD>"+expectBase+"foo")
c.Run("Inject after head tag when doctype and html omitted", func(c *qt.C) {
c.Assert(apply("<head>after"), qt.Equals, "<head>"+expectBase+"after")
})

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

c.Run("Body upper", func(c *qt.C) {
c.Assert(apply("foo</BODY>"), qt.Equals, "foo"+expectBase+"</BODY>")
c.Run("Inject after doctype when head and html omitted", func(c *qt.C) {
c.Assert(apply("<!doctype html>after"), qt.Equals, "<!doctype html>"+expectBase+"after")
})

c.Run("Html upper", func(c *qt.C) {
c.Assert(apply("<html>foo"), qt.Equals, "<html>"+expectBase+warnScript+"foo")
c.Run("Inject before other elements if all else omitted", func(c *qt.C) {
c.Assert(apply("<title>after</title>"), qt.Equals, expectBase+"<title>after</title>")
})

c.Run("Html upper with attr", func(c *qt.C) {
c.Assert(apply(`<html lang="en">foo`), qt.Equals, `<html lang="en">`+expectBase+warnScript+"foo")
c.Run("Inject before text content if all else omitted", func(c *qt.C) {
c.Assert(apply("after"), qt.Equals, expectBase+"after")
})

c.Run("No match", func(c *qt.C) {
c.Assert(apply("<h1>No match</h1>"), qt.Equals, "<h1>No match</h1>"+expectBase+warnScript)
c.Run("Inject after HeAd tag MiXed CaSe", func(c *qt.C) {
c.Assert(apply("<HeAd>AfTer"), qt.Equals, "<HeAd>"+expectBase+"AfTer")
})

c.Run("Inject after HtMl tag MiXed CaSe", func(c *qt.C) {
c.Assert(apply("<HtMl>AfTer"), qt.Equals, "<HtMl>"+expectBase+"AfTer")
})

c.Run("Inject after doctype mixed case", func(c *qt.C) {
c.Assert(apply("<!DocType HtMl>AfTer"), qt.Equals, "<!DocType HtMl>"+expectBase+"AfTer")
})

c.Run("Inject after html tag with attributes", func(c *qt.C) {
c.Assert(apply(`<html lang="en">after`), qt.Equals, `<html lang="en">`+expectBase+"after")
})

c.Run("Inject after html tag with newline", func(c *qt.C) {
c.Assert(apply("<html\n>after"), qt.Equals, "<html\n>"+expectBase+"after")
})

c.Run("Skip comments and whitespace", func(c *qt.C) {
c.Assert(
apply(" <!--x--> <!doctype html>\n<?xml instruction ?> <head>after"),
qt.Equals,
" <!--x--> <!doctype html>\n<?xml instruction ?> <head>"+expectBase+"after",
)
})

c.Run("Do not search inside comment", func(c *qt.C) {
c.Assert(apply("<html><!--<head>-->"), qt.Equals, "<html><!--<head>-->"+expectBase)
})

c.Run("Do not search inside scripts", func(c *qt.C) {
c.Assert(apply("<html><script>`<head>`</script>"), qt.Equals, "<html>"+expectBase+"<script>`<head>`</script>")
})

c.Run("Do not search inside templates", func(c *qt.C) {
c.Assert(apply("<html><template><head></template>"), qt.Not(qt.Equals), "<html><template><head>"+expectBase+"</template>")
})

c.Run("Search from the start of the input", func(c *qt.C) {
c.Assert(apply("<head>after<head>"), qt.Equals, "<head>"+expectBase+"after<head>")
})

c.Run("Do not mistake header for head", func(c *qt.C) {
c.Assert(apply("<html><header>"), qt.Equals, "<html>"+expectBase+"<header>")
})

c.Run("Do not mistake custom elements for head", func(c *qt.C) {
c.Assert(apply("<html><head-custom>"), qt.Equals, "<html>"+expectBase+"<head-custom>")
})
}

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