message.go

package message

import (
	"errors"
	"strings"

	"github.com/ipfs/go-cid"
	"github.com/multiformats/go-multiaddr"
)

var ErrBadEncoding = errors.New("invalid message encoding")

// Message announces the availability of an IPNI advertisement..
type Message struct {
	// Cid identifies the advertisement being announced.
	Cid cid.Cid
	// Addrs contains a set of multiaddrs that specify where the announced
	// advertisement is available. See SetAddrs and GetAddrs.
	Addrs [][]byte
	// ExtraData is optional data indended for a certain recipients. For
	// example, a publisher may include its storage provider ID for validation
	// by a gateway.
	ExtraData []byte
	// The OrigPeer field may or may not be present in the serialized data, and
	// the CBOR serializer/deserializer is able to detect that. Only messages
	// that are re-published by an indexer, for consumption by othen indexers,
	// contain this field.
	OrigPeer string
}

// SetAddrs writes a slice of Multiaddr into the Message as a slice of []byte.
func (m *Message) SetAddrs(addrs []multiaddr.Multiaddr) {
	m.Addrs = make([][]byte, len(addrs))
	for i, a := range addrs {
		m.Addrs[i] = a.Bytes()
	}
}

// GetAddrs reads the slice of Multiaddr that is stored in the Message as a
// slice of []byte.
func (m *Message) GetAddrs() ([]multiaddr.Multiaddr, error) {
	addrs := make([]multiaddr.Multiaddr, 0, len(m.Addrs))
	for _, addrBytes := range m.Addrs {
		addr, err := multiaddr.NewMultiaddrBytes(addrBytes)
		if err != nil {
			if strings.Contains(err.Error(), "no protocol with code") {
				// Ignore unknown protocols.
				continue
			}
			return nil, err
		}
		addrs = append(addrs, addr)
	}
	return addrs, nil
}