github.com/anakojm/hugo-katex@v0.0.0-20231023141351-42d6f5de9c0b/parser/lowercase_camel_json.go (about) 1 // Copyright 2019 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 "bytes" 18 "encoding/json" 19 "regexp" 20 "unicode" 21 "unicode/utf8" 22 23 "github.com/gohugoio/hugo/common/hreflect" 24 ) 25 26 // Regexp definitions 27 var ( 28 keyMatchRegex = regexp.MustCompile(`\"(\w+)\":`) 29 wordBarrierRegex = regexp.MustCompile(`(\w)([A-Z])`) 30 ) 31 32 // Code adapted from https://gist.github.com/piersy/b9934790a8892db1a603820c0c23e4a7 33 type LowerCaseCamelJSONMarshaller struct { 34 Value any 35 } 36 37 func (c LowerCaseCamelJSONMarshaller) MarshalJSON() ([]byte, error) { 38 marshalled, err := json.Marshal(c.Value) 39 40 converted := keyMatchRegex.ReplaceAllFunc( 41 marshalled, 42 func(match []byte) []byte { 43 // Attributes on the form XML, JSON etc. 44 if bytes.Equal(match, bytes.ToUpper(match)) { 45 return bytes.ToLower(match) 46 } 47 48 // Empty keys are valid JSON, only lowercase if we do not have an 49 // empty key. 50 if len(match) > 2 { 51 // Decode first rune after the double quotes 52 r, width := utf8.DecodeRune(match[1:]) 53 r = unicode.ToLower(r) 54 utf8.EncodeRune(match[1:width+1], r) 55 } 56 return match 57 }, 58 ) 59 60 return converted, err 61 } 62 63 type ReplacingJSONMarshaller struct { 64 Value any 65 66 KeysToLower bool 67 OmitEmpty bool 68 } 69 70 func (c ReplacingJSONMarshaller) MarshalJSON() ([]byte, error) { 71 converted, err := json.Marshal(c.Value) 72 73 if c.KeysToLower { 74 converted = keyMatchRegex.ReplaceAllFunc( 75 converted, 76 func(match []byte) []byte { 77 return bytes.ToLower(match) 78 }, 79 ) 80 } 81 82 if c.OmitEmpty { 83 // It's tricky to do this with a regexp, so convert it to a map, remove zero values and convert back. 84 var m map[string]interface{} 85 err = json.Unmarshal(converted, &m) 86 if err != nil { 87 return nil, err 88 } 89 var removeZeroVAlues func(m map[string]any) 90 removeZeroVAlues = func(m map[string]any) { 91 for k, v := range m { 92 if !hreflect.IsTruthful(v) { 93 delete(m, k) 94 } else { 95 switch v.(type) { 96 case map[string]interface{}: 97 removeZeroVAlues(v.(map[string]any)) 98 case []interface{}: 99 for _, vv := range v.([]interface{}) { 100 if m, ok := vv.(map[string]any); ok { 101 removeZeroVAlues(m) 102 } 103 } 104 } 105 106 } 107 108 } 109 } 110 removeZeroVAlues(m) 111 converted, err = json.Marshal(m) 112 113 } 114 115 return converted, err 116 }