ba129ebd42
Users can provide a function to transcode an encoded CBOR data item to JSON. If provided, then unmarshaling into a value whose type implements json.Unmarshaler, but not cbor.Unmarshaler, will first transcode the input bytes to JSON and then invoke UnmarshalJSON on the destination value. Signed-off-by: Ben Luddy <bluddy@redhat.com>
86 lines
2.0 KiB
Go
86 lines
2.0 KiB
Go
// Copyright (c) Faye Amacker. All rights reserved.
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// Licensed under the MIT License. See LICENSE in the project root for license information.
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package cbor_test
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import (
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"encoding/json"
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"fmt"
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"io"
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"reflect"
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"github.com/fxamacker/cbor/v2"
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)
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type TranscoderFunc func(io.Writer, io.Reader) error
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func (f TranscoderFunc) Transcode(w io.Writer, r io.Reader) error {
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return f(w, r)
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}
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func ExampleTranscoder_fromJSON() {
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enc, _ := cbor.EncOptions{
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JSONMarshalerTranscoder: TranscoderFunc(func(w io.Writer, r io.Reader) error {
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d := json.NewDecoder(r)
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for {
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token, err := d.Token()
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if err == io.EOF {
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return nil
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}
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if err != nil {
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return err
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}
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switch token {
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case json.Delim('['):
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if _, err := w.Write([]byte{0x9f}); err != nil {
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return err
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}
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case json.Delim('{'):
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if _, err := w.Write([]byte{0xbf}); err != nil {
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return err
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}
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case json.Delim(']'), json.Delim('}'):
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if _, err := w.Write([]byte{0xff}); err != nil {
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return err
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}
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default:
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b, err := cbor.Marshal(token)
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if err != nil {
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return err
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}
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if _, err := w.Write(b); err != nil {
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return err
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}
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}
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}
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}),
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}.EncMode()
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got, _ := enc.Marshal(json.RawMessage(`{"a": [true, "z", {"y": 3.14}], "b": {"c": null}}`))
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diag, _ := cbor.Diagnose(got)
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fmt.Println(diag)
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// Output: {_ "a": [_ true, "z", {_ "y": 3.14}], "b": {_ "c": null}}
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}
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func ExampleTranscoder_toJSON() {
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var dec cbor.DecMode
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dec, _ = cbor.DecOptions{
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DefaultMapType: reflect.TypeOf(map[string]any{}),
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JSONUnmarshalerTranscoder: TranscoderFunc(func(w io.Writer, r io.Reader) error {
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var tmp any
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if err := dec.NewDecoder(r).Decode(&tmp); err != nil {
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return err
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}
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return json.NewEncoder(w).Encode(tmp)
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}),
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}.DecMode()
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var got json.RawMessage
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if err := dec.Unmarshal(cbor.RawMessage{0xa2, 0x61, 'a', 0x01, 0x61, 'b', 0x83, 0xf4, 0xf5, 0xf6}, &got); err != nil {
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panic(err)
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}
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fmt.Println(string(got))
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// Output: {"a":1,"b":[false,true,null]}
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}
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