github.com/gohugoio/hugo@v0.88.1/parser/frontmatter.go (about)

     1  // Copyright 2015 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 parser
    15  
    16  import (
    17  	"encoding/json"
    18  	"errors"
    19  	"io"
    20  
    21  	"github.com/gohugoio/hugo/parser/metadecoders"
    22  
    23  	toml "github.com/pelletier/go-toml/v2"
    24  
    25  	yaml "gopkg.in/yaml.v2"
    26  )
    27  
    28  const (
    29  	yamlDelimLf = "---\n"
    30  	tomlDelimLf = "+++\n"
    31  )
    32  
    33  func InterfaceToConfig(in interface{}, format metadecoders.Format, w io.Writer) error {
    34  	if in == nil {
    35  		return errors.New("input was nil")
    36  	}
    37  
    38  	switch format {
    39  	case metadecoders.YAML:
    40  		b, err := yaml.Marshal(in)
    41  		if err != nil {
    42  			return err
    43  		}
    44  
    45  		_, err = w.Write(b)
    46  		return err
    47  
    48  	case metadecoders.TOML:
    49  		enc := toml.NewEncoder(w)
    50  		enc.SetIndentTables(true)
    51  		return enc.Encode(in)
    52  	case metadecoders.JSON:
    53  		b, err := json.MarshalIndent(in, "", "   ")
    54  		if err != nil {
    55  			return err
    56  		}
    57  
    58  		_, err = w.Write(b)
    59  		if err != nil {
    60  			return err
    61  		}
    62  
    63  		_, err = w.Write([]byte{'\n'})
    64  		return err
    65  
    66  	default:
    67  		return errors.New("unsupported Format provided")
    68  	}
    69  }
    70  
    71  func InterfaceToFrontMatter(in interface{}, format metadecoders.Format, w io.Writer) error {
    72  	if in == nil {
    73  		return errors.New("input was nil")
    74  	}
    75  
    76  	switch format {
    77  	case metadecoders.YAML:
    78  		_, err := w.Write([]byte(yamlDelimLf))
    79  		if err != nil {
    80  			return err
    81  		}
    82  
    83  		err = InterfaceToConfig(in, format, w)
    84  		if err != nil {
    85  			return err
    86  		}
    87  
    88  		_, err = w.Write([]byte(yamlDelimLf))
    89  		return err
    90  
    91  	case metadecoders.TOML:
    92  		_, err := w.Write([]byte(tomlDelimLf))
    93  		if err != nil {
    94  			return err
    95  		}
    96  
    97  		err = InterfaceToConfig(in, format, w)
    98  
    99  		if err != nil {
   100  			return err
   101  		}
   102  
   103  		_, err = w.Write([]byte("\n" + tomlDelimLf))
   104  		return err
   105  
   106  	default:
   107  		return InterfaceToConfig(in, format, w)
   108  	}
   109  }