73 lines
1.4 KiB
Go
73 lines
1.4 KiB
Go
package did
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import (
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"fmt"
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"strings"
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mbase "github.com/multiformats/go-multibase"
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varint "github.com/multiformats/go-varint"
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)
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const Prefix = "did:"
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const KeyPrefix = "did:key:"
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const Ed25519 = 0xed
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type DID struct {
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str string
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}
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// Undef can be used to represent a nil or undefined DID, using DID{}
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// directly is also acceptable.
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var Undef = DID{}
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func (d DID) Defined() bool {
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return d.str != ""
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}
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func (d DID) Bytes() []byte {
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if !d.Defined() {
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return nil
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}
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return []byte(d.str)
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}
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func (d DID) DID() DID {
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return d
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}
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func (d DID) String() string {
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key, _ := mbase.Encode(mbase.Base58BTC, []byte(d.str))
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return "did:key:" + key
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}
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func Decode(bytes []byte) (DID, error) {
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code, _, err := varint.FromUvarint(bytes)
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if err != nil {
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return Undef, err
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}
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if code == Ed25519 {
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return DID{str: string(bytes)}, nil
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}
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return Undef, fmt.Errorf("decoding DID: unsupported DID encoding: 0x%x", code)
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}
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func Parse(str string) (DID, error) {
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if !strings.HasPrefix(str, Prefix) {
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return Undef, fmt.Errorf("parsing DID: must start with 'did:'")
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}
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if strings.HasPrefix(str, KeyPrefix) {
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code, bytes, err := mbase.Decode(str[len(KeyPrefix):])
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if err != nil {
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return Undef, err
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}
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if code != mbase.Base58BTC {
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return Undef, fmt.Errorf("parsing DID key: not Base58BTC encoded")
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}
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return Decode(bytes)
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}
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return Undef, fmt.Errorf("parsing DID: unsupported method")
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}
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