2 files changed, 115 insertions, 0 deletions
diff --git a/transform/metainject/hugogenerator.go b/transform/metainject/hugogenerator.go
new file mode 100644
index 000000000..513b21228
--- /dev/null
+++ b/transform/metainject/hugogenerator.go
@@ -0,0 +1,54 @@
+// 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 metainject
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+
+	"github.com/gohugoio/hugo/helpers"
+	"github.com/gohugoio/hugo/transform"
+)
+
+var metaTagsCheck = regexp.MustCompile(`(?i)<meta\s+name=['|"]?generator['|"]?`)
+var hugoGeneratorTag = fmt.Sprintf(`<meta name="generator" content="Hugo %s" />`, helpers.CurrentHugoVersion)
+
+// HugoGenerator injects a meta generator tag for Hugo if none present.
+func HugoGenerator(ft transform.FromTo) error {
+	b := ft.From().Bytes()
+	if metaTagsCheck.Match(b) {
+		if _, err := ft.To().Write(b); err != nil {
+			helpers.DistinctWarnLog.Println("Failed to inject Hugo generator tag:", err)
+		}
+		return nil
+	}
+
+	head := "<head>"
+	replace := []byte(fmt.Sprintf("%s\n\t%s", head, hugoGeneratorTag))
+	newcontent := bytes.Replace(b, []byte(head), replace, 1)
+
+	if len(newcontent) == len(b) {
+		head := "<HEAD>"
+		replace := []byte(fmt.Sprintf("%s\n\t%s", head, hugoGeneratorTag))
+		newcontent = bytes.Replace(b, []byte(head), replace, 1)
+	}
+
+	if _, err := ft.To().Write(newcontent); err != nil {
+		helpers.DistinctWarnLog.Println("Failed to inject Hugo generator tag:", err)
+	}
+
+	return nil
+
+}
diff --git a/transform/metainject/hugogenerator_test.go b/transform/metainject/hugogenerator_test.go
new file mode 100644
index 000000000..ffb4c1425
--- /dev/null
+++ b/transform/metainject/hugogenerator_test.go
@@ -0,0 +1,61 @@
+// 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 metainject
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/gohugoio/hugo/transform"
+)
+
+func TestHugoGeneratorInject(t *testing.T) {
+	hugoGeneratorTag = "META"
+	for i, this := range []struct {
+		in     string
+		expect string
+	}{
+		{`<head>
+	<foo />
+</head>`, `<head>
+	META
+	<foo />
+</head>`},
+		{`<HEAD>
+	<foo />
+</HEAD>`, `<HEAD>
+	META
+	<foo />
+</HEAD>`},
+		{`<head><meta name="generator" content="Jekyll" /></head>`, `<head><meta name="generator" content="Jekyll" /></head>`},
+		{`<head><meta name='generator' content='Jekyll' /></head>`, `<head><meta name='generator' content='Jekyll' /></head>`},
+		{`<head><meta name=generator content=Jekyll /></head>`, `<head><meta name=generator content=Jekyll /></head>`},
+		{`<head><META     NAME="GENERATOR" content="Jekyll" /></head>`, `<head><META     NAME="GENERATOR" content="Jekyll" /></head>`},
+		{"", ""},
+		{"</head>", "</head>"},
+		{"<head>", "<head>\n\tMETA"},
+	} {
+		in := strings.NewReader(this.in)
+		out := new(bytes.Buffer)
+
+		tr := transform.New(HugoGenerator)
+		tr.Apply(out, in)
+
+		if out.String() != this.expect {
+			t.Errorf("[%d] Expected \n%q got \n%q", i, this.expect, out.String())
+		}
+	}
+
+}