func selectRecord(recs []*pb.IpnsEntry, vals [][]byte) (int, error) {
var best_seq uint64
best_i := -1
for i, r := range recs {
if r == nil || r.GetSequence() < best_seq {
continue
}
if best_i == -1 || r.GetSequence() > best_seq {
best_seq = r.GetSequence()
best_i = i
} else if r.GetSequence() == best_seq {
rt, err := u.ParseRFC3339(string(r.GetValidity()))
if err != nil {
continue
}
bestt, err := u.ParseRFC3339(string(recs[best_i].GetValidity()))
if err != nil {
continue
}
if rt.After(bestt) {
best_i = i
} else if rt == bestt {
if bytes.Compare(vals[i], vals[best_i]) > 0 {
best_i = i
}
}
}
}
if best_i == -1 {
return 0, errors.New("no usable records in given set")
}
return best_i, nil
}
// ValidateIpnsRecord implements ValidatorFunc and verifies that the
// given 'val' is an IpnsEntry and that that entry is valid.
func ValidateIpnsRecord(k key.Key, val []byte) error {
entry := new(pb.IpnsEntry)
err := proto.Unmarshal(val, entry)
if err != nil {
return err
}
switch entry.GetValidityType() {
case pb.IpnsEntry_EOL:
t, err := u.ParseRFC3339(string(entry.GetValidity()))
if err != nil {
log.Debug("Failed parsing time for ipns record EOL")
return err
}
if time.Now().After(t) {
return ErrExpiredRecord
}
default:
return ErrUnrecognizedValidity
}
return nil
}
func (dht *IpfsDHT) checkLocalDatastore(k key.Key) (*pb.Record, error) {
log.Debugf("%s handleGetValue looking into ds", dht.self)
dskey := k.DsKey()
iVal, err := dht.datastore.Get(dskey)
log.Debugf("%s handleGetValue looking into ds GOT %v", dht.self, iVal)
if err == ds.ErrNotFound {
return nil, nil
}
// if we got an unexpected error, bail.
if err != nil {
return nil, err
}
// if we have the value, send it back
log.Debugf("%s handleGetValue success!", dht.self)
byts, ok := iVal.([]byte)
if !ok {
return nil, fmt.Errorf("datastore had non byte-slice value for %v", dskey)
}
rec := new(pb.Record)
err = proto.Unmarshal(byts, rec)
if err != nil {
log.Debug("Failed to unmarshal dht record from datastore")
return nil, err
}
// if its our record, dont bother checking the times on it
if peer.ID(rec.GetAuthor()) == dht.self {
return rec, nil
}
var recordIsBad bool
recvtime, err := u.ParseRFC3339(rec.GetTimeReceived())
if err != nil {
log.Info("either no receive time set on record, or it was invalid: ", err)
recordIsBad = true
}
if time.Now().Sub(recvtime) > MaxRecordAge {
log.Debug("old record found, tossing.")
recordIsBad = true
}
// NOTE: we do not verify the record here beyond checking these timestamps.
// we put the burden of checking the records on the requester as checking a record
// may be computationally expensive
if recordIsBad {
err := dht.datastore.Delete(dskey)
if err != nil {
log.Error("Failed to delete bad record from datastore: ", err)
}
return nil, nil // can treat this as not having the record at all
}
return rec, nil
}