|
| 1 | +package datauri |
| 2 | + |
| 3 | +import ( |
| 4 | + "encoding" |
| 5 | + "encoding/base64" |
| 6 | + "errors" |
| 7 | + "mime" |
| 8 | + "net/url" |
| 9 | + "strings" |
| 10 | +) |
| 11 | + |
| 12 | +var ( |
| 13 | + ErrInvalidDataURI = errors.New("invalid data uri") |
| 14 | +) |
| 15 | + |
| 16 | +func Parse(dataURI string) (*DataURI, error) { |
| 17 | + withoutPrefix := "" |
| 18 | + if strings.HasPrefix(dataURI, "data:") { |
| 19 | + withoutPrefix = strings.TrimPrefix(dataURI, "data:") |
| 20 | + } else { |
| 21 | + withoutPrefix = ",;base64," + dataURI |
| 22 | + } |
| 23 | + |
| 24 | + parts := strings.SplitN(withoutPrefix, ",", 2) |
| 25 | + if len(parts) != 2 { |
| 26 | + return nil, ErrInvalidDataURI |
| 27 | + } |
| 28 | + |
| 29 | + meta, raw := parts[0], parts[1] |
| 30 | + isBase64 := strings.Contains(meta, ";base64") |
| 31 | + if isBase64 { |
| 32 | + meta = strings.Replace(meta, ";base64", "", 1) |
| 33 | + } |
| 34 | + |
| 35 | + mediaType, params, err := mime.ParseMediaType(meta) |
| 36 | + if err != nil { |
| 37 | + mediaType = "" |
| 38 | + } |
| 39 | + |
| 40 | + d := &DataURI{ |
| 41 | + MediaType: mediaType, |
| 42 | + Params: params, |
| 43 | + } |
| 44 | + |
| 45 | + if isBase64 { |
| 46 | + data, err := base64.StdEncoding.DecodeString(raw) |
| 47 | + if err != nil { |
| 48 | + return nil, errors.Join(ErrInvalidDataURI, err) |
| 49 | + } |
| 50 | + d.Data = data |
| 51 | + |
| 52 | + return d, nil |
| 53 | + } |
| 54 | + |
| 55 | + s, err := url.PathUnescape(raw) |
| 56 | + if err != nil { |
| 57 | + return nil, errors.Join(ErrInvalidDataURI, err) |
| 58 | + } |
| 59 | + |
| 60 | + d.Data = []byte(s) |
| 61 | + |
| 62 | + return d, nil |
| 63 | +} |
| 64 | + |
| 65 | +type DataURI struct { |
| 66 | + MediaType string |
| 67 | + Params map[string]string |
| 68 | + Data []byte |
| 69 | +} |
| 70 | + |
| 71 | +func (d DataURI) IsZero() bool { |
| 72 | + return len(d.Data) == 0 |
| 73 | +} |
| 74 | + |
| 75 | +func (DataURI) OpenAPISchemaFormat() string { |
| 76 | + return "data-uri" |
| 77 | +} |
| 78 | + |
| 79 | +func (d *DataURI) Encoded(base64Encoded bool) string { |
| 80 | + s := &strings.Builder{} |
| 81 | + s.WriteString("data:") |
| 82 | + s.WriteString(strings.ReplaceAll(mime.FormatMediaType(d.MediaType, d.Params), "; ", ";")) |
| 83 | + |
| 84 | + if base64Encoded { |
| 85 | + s.WriteString(";base64,") |
| 86 | + s.WriteString(base64.StdEncoding.EncodeToString(d.Data)) |
| 87 | + } else { |
| 88 | + s.WriteString(",") |
| 89 | + s.WriteString(url.PathEscape(string(d.Data))) |
| 90 | + } |
| 91 | + return s.String() |
| 92 | +} |
| 93 | + |
| 94 | +func (d DataURI) String() string { |
| 95 | + return d.Encoded(true) |
| 96 | +} |
| 97 | + |
| 98 | +var _ encoding.TextMarshaler = (*DataURI)(nil) |
| 99 | + |
| 100 | +func (d DataURI) MarshalText() ([]byte, error) { |
| 101 | + return []byte(d.Encoded(true)), nil |
| 102 | +} |
| 103 | + |
| 104 | +var _ encoding.TextUnmarshaler = (*DataURI)(nil) |
| 105 | + |
| 106 | +func (d *DataURI) UnmarshalText(text []byte) error { |
| 107 | + dd, err := Parse(string(text)) |
| 108 | + if err != nil { |
| 109 | + return err |
| 110 | + } |
| 111 | + *d = *dd |
| 112 | + return nil |
| 113 | +} |
0 commit comments