1package message
 2
 3import (
 4	"encoding/base64"
 5	"encoding/json"
 6)
 7
 8type Attachment struct {
 9	FilePath string `json:"file_path"`
10	FileName string `json:"file_name"`
11	MimeType string `json:"mime_type"`
12	Content  []byte `json:"content"`
13}
14
15// MarshalJSON implements the [json.Marshaler] interface.
16func (a Attachment) MarshalJSON() ([]byte, error) {
17	// Encode the content as a base64 string
18	type Alias Attachment
19	return json.Marshal(&struct {
20		Content string `json:"content"`
21		*Alias
22	}{
23		Content: base64.StdEncoding.EncodeToString(a.Content),
24		Alias:   (*Alias)(&a),
25	})
26}
27
28// UnmarshalJSON implements the [json.Unmarshaler] interface.
29func (a *Attachment) UnmarshalJSON(data []byte) error {
30	// Decode the content from a base64 string
31	type Alias Attachment
32	aux := &struct {
33		Content string `json:"content"`
34		*Alias
35	}{
36		Alias: (*Alias)(a),
37	}
38	if err := json.Unmarshal(data, &aux); err != nil {
39		return err
40	}
41	content, err := base64.StdEncoding.DecodeString(aux.Content)
42	if err != nil {
43		return err
44	}
45	a.Content = content
46	return nil
47}