github.com/SuCicada/su-hugo@v1.0.0/parser/metadecoders/format.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 metadecoders
    15  
    16  import (
    17  	"path/filepath"
    18  	"strings"
    19  
    20  	"github.com/gohugoio/hugo/media"
    21  )
    22  
    23  type Format string
    24  
    25  const (
    26  	// These are the supported metdata  formats in Hugo. Most of these are also
    27  	// supported as /data formats.
    28  	ORG  Format = "org"
    29  	JSON Format = "json"
    30  	TOML Format = "toml"
    31  	YAML Format = "yaml"
    32  	CSV  Format = "csv"
    33  	XML  Format = "xml"
    34  )
    35  
    36  // FormatFromString turns formatStr, typically a file extension without any ".",
    37  // into a Format. It returns an empty string for unknown formats.
    38  func FormatFromString(formatStr string) Format {
    39  	formatStr = strings.ToLower(formatStr)
    40  	if strings.Contains(formatStr, ".") {
    41  		// Assume a filename
    42  		formatStr = strings.TrimPrefix(filepath.Ext(formatStr), ".")
    43  	}
    44  	switch formatStr {
    45  	case "yaml", "yml":
    46  		return YAML
    47  	case "json":
    48  		return JSON
    49  	case "toml":
    50  		return TOML
    51  	case "org":
    52  		return ORG
    53  	case "csv":
    54  		return CSV
    55  	case "xml":
    56  		return XML
    57  	}
    58  
    59  	return ""
    60  }
    61  
    62  // FormatFromMediaType gets the Format given a MIME type, empty string
    63  // if unknown.
    64  func FormatFromMediaType(m media.Type) Format {
    65  	for _, suffix := range m.Suffixes() {
    66  		if f := FormatFromString(suffix); f != "" {
    67  			return f
    68  		}
    69  	}
    70  
    71  	return ""
    72  }
    73  
    74  // FormatFromContentString tries to detect the format (JSON, YAML, TOML or XML)
    75  // in the given string.
    76  // It return an empty string if no format could be detected.
    77  func (d Decoder) FormatFromContentString(data string) Format {
    78  	csvIdx := strings.IndexRune(data, d.Delimiter)
    79  	jsonIdx := strings.Index(data, "{")
    80  	yamlIdx := strings.Index(data, ":")
    81  	xmlIdx := strings.Index(data, "<")
    82  	tomlIdx := strings.Index(data, "=")
    83  
    84  	if isLowerIndexThan(csvIdx, jsonIdx, yamlIdx, xmlIdx, tomlIdx) {
    85  		return CSV
    86  	}
    87  
    88  	if isLowerIndexThan(jsonIdx, yamlIdx, xmlIdx, tomlIdx) {
    89  		return JSON
    90  	}
    91  
    92  	if isLowerIndexThan(yamlIdx, xmlIdx, tomlIdx) {
    93  		return YAML
    94  	}
    95  
    96  	if isLowerIndexThan(xmlIdx, tomlIdx) {
    97  		return XML
    98  	}
    99  
   100  	if tomlIdx != -1 {
   101  		return TOML
   102  	}
   103  
   104  	return ""
   105  }
   106  
   107  func isLowerIndexThan(first int, others ...int) bool {
   108  	if first == -1 {
   109  		return false
   110  	}
   111  	for _, other := range others {
   112  		if other != -1 && other < first {
   113  			return false
   114  		}
   115  	}
   116  
   117  	return true
   118  }