github.com/graemephi/kahugo@v0.62.3-0.20211121071557-d78c0423784d/transform/metainject/hugogenerator.go (about)

     1  // Copyright 2018 The Hugo Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package metainject
    15  
    16  import (
    17  	"bytes"
    18  	"fmt"
    19  	"regexp"
    20  
    21  	"github.com/gohugoio/hugo/common/hugo"
    22  	"github.com/gohugoio/hugo/helpers"
    23  	"github.com/gohugoio/hugo/transform"
    24  )
    25  
    26  var (
    27  	metaTagsCheck    = regexp.MustCompile(`(?i)<meta\s+name=['|"]?generator['|"]?`)
    28  	hugoGeneratorTag = fmt.Sprintf(`<meta name="generator" content="Hugo %s" />`, hugo.CurrentVersion)
    29  )
    30  
    31  // HugoGenerator injects a meta generator tag for Hugo if none present.
    32  func HugoGenerator(ft transform.FromTo) error {
    33  	b := ft.From().Bytes()
    34  	if metaTagsCheck.Match(b) {
    35  		if _, err := ft.To().Write(b); err != nil {
    36  			helpers.DistinctWarnLog.Println("Failed to inject Hugo generator tag:", err)
    37  		}
    38  		return nil
    39  	}
    40  
    41  	head := "<head>"
    42  	replace := []byte(fmt.Sprintf("%s\n\t%s", head, hugoGeneratorTag))
    43  	newcontent := bytes.Replace(b, []byte(head), replace, 1)
    44  
    45  	if len(newcontent) == len(b) {
    46  		head := "<HEAD>"
    47  		replace := []byte(fmt.Sprintf("%s\n\t%s", head, hugoGeneratorTag))
    48  		newcontent = bytes.Replace(b, []byte(head), replace, 1)
    49  	}
    50  
    51  	if _, err := ft.To().Write(newcontent); err != nil {
    52  		helpers.DistinctWarnLog.Println("Failed to inject Hugo generator tag:", err)
    53  	}
    54  
    55  	return nil
    56  }