// getLocal attempts to retrieve the value from the datastore
func (dht *IpfsDHT) getLocal(key key.Key) ([]byte, error) {
log.Debug("getLocal %s", key)
v, err := dht.datastore.Get(key.DsKey())
if err != nil {
return nil, err
}
log.Debug("found in db")
byt, ok := v.([]byte)
if !ok {
return nil, errors.New("value stored in datastore not []byte")
}
rec := new(pb.Record)
err = proto.Unmarshal(byt, rec)
if err != nil {
return nil, err
}
// TODO: 'if paranoid'
if u.Debug {
err = dht.verifyRecordLocally(rec)
if err != nil {
log.Debugf("local record verify failed: %s (discarded)", err)
return nil, err
}
}
return rec.GetValue(), nil
}
func verify(ps peer.Peerstore, r *dhtpb.Record) error {
v := make(record.Validator)
v["pk"] = record.PublicKeyValidator
p := peer.ID(r.GetAuthor())
pk := ps.PubKey(p)
if pk == nil {
return fmt.Errorf("do not have public key for %s", p)
}
if err := record.CheckRecordSig(r, pk); err != nil {
return err
}
if err := v.VerifyRecord(r); err != nil {
return err
}
return nil
}
func (c *offlineRouting) GetValue(ctx context.Context, key key.Key) ([]byte, error) {
v, err := c.datastore.Get(key.DsKey())
if err != nil {
return nil, err
}
byt, ok := v.([]byte)
if !ok {
return nil, errors.New("value stored in datastore not []byte")
}
rec := new(pb.Record)
err = proto.Unmarshal(byt, rec)
if err != nil {
return nil, err
}
return rec.GetValue(), nil
}
// VerifyRecord checks a record and ensures it is still valid.
// It runs needed validators
func (v Validator) VerifyRecord(r *pb.Record) error {
// Now, check validity func
parts := strings.Split(r.GetKey(), "/")
if len(parts) < 3 {
log.Infof("Record key does not have validator: %s", key.Key(r.GetKey()))
return nil
}
val, ok := v[parts[1]]
if !ok {
log.Infof("Unrecognized key prefix: %s", parts[1])
return ErrInvalidRecordType
}
return val.Func(key.Key(r.GetKey()), r.GetValue())
}
// MakePutRecord creates and signs a dht record for the given key/value pair
func MakePutRecord(sk ci.PrivKey, key key.Key, value []byte, sign bool) (*pb.Record, error) {
record := new(pb.Record)
record.Key = proto.String(string(key))
record.Value = value
pkh, err := sk.GetPublic().Hash()
if err != nil {
return nil, err
}
record.Author = proto.String(string(pkh))
if sign {
blob := RecordBlobForSig(record)
sig, err := sk.Sign(blob)
if err != nil {
return nil, err
}
record.Signature = sig
}
return record, nil
}
// RecordBlobForSig returns the blob protected by the record signature
func RecordBlobForSig(r *pb.Record) []byte {
k := []byte(r.GetKey())
v := []byte(r.GetValue())
a := []byte(r.GetAuthor())
return bytes.Join([][]byte{k, v, a}, []byte{})
}