oppi.li
1package data
2
3import (
4 "bytes"
5 "encoding/json"
6 "fmt"
7 "io"
8)
9
10// Helper type for extracting record $type from CBOR
11type GenericRecord struct {
12 Type string `json:"$type" cborgen:"$type"`
13}
14
15// Parses the top-level $type field from generic atproto JSON data
16func ExtractTypeJSON(b []byte) (string, error) {
17 var gr GenericRecord
18 if err := json.Unmarshal(b, &gr); err != nil {
19 return "", err
20 }
21
22 return gr.Type, nil
23}
24
25// Parses the top-level $type field from generic atproto CBOR data
26func ExtractTypeCBOR(b []byte) (string, error) {
27 var gr GenericRecord
28 if err := gr.UnmarshalCBOR(bytes.NewReader(b)); err != nil {
29 fmt.Printf("bad bytes: %x\n", b)
30 return "", err
31 }
32
33 return gr.Type, nil
34}
35
36// Parses top-level $type field from generic atproto CBOR.
37//
38// Returns that string field, and additional bytes (TODO: the parsed bytes, or remaining bytes?)
39func ExtractTypeCBORReader(r io.Reader) (string, []byte, error) {
40 buf := new(bytes.Buffer)
41 tr := io.TeeReader(r, buf)
42 var gr GenericRecord
43 if err := gr.UnmarshalCBOR(tr); err != nil {
44 return "", nil, err
45 }
46
47 return gr.Type, buf.Bytes(), nil
48}