// Save the current set of reachable DHT nodes to disk.
func Save(filename string, dht *dht.DHT) error {
d := doc{
NodeID: dht.NodeID(),
}
nodes := dht.ListReachableNodes()
for i := range nodes {
d.Nodes = append(d.Nodes, node{
NodeID: nodes[i].NodeID.String(),
Addr: nodes[i].Addr.String(),
})
}
b, err := json.Marshal(&d)
if err != nil {
return err
}
tfilename := filename + ".tmp"
defer os.Remove(tfilename)
err = ioutil.WriteFile(tfilename, b, 0644)
if err != nil {
return err
}
return os.Rename(tfilename, filename)
}
// Loads the node database into the running DHT. Call this just after running the DHT.
func (ds *DHTStorage) LoadDHT(d *dht.DHT) error {
db, err := ds.getDB()
if err != nil {
return err
}
defer db.Close()
err = ds.createTablesWith(db)
if err != nil {
return err
}
r, err := db.Query(`SELECT hostname,node_id FROM dht_routers`)
if err != nil {
return err
}
defer r.Close()
for r.Next() {
var hostname string
var node_id interface{}
err = r.Scan(&hostname, &node_id)
if err != nil {
return err
}
node_id_s, ok := node_id.([]byte)
if !ok {
node_id_s = []byte{}
}
node_id_bin, err := hex.DecodeString(string(node_id_s))
if err != nil {
node_id_bin = []byte{}
}
unused(node_id)
d.AddNode(hostname, string(node_id_bin))
}
return nil
}
// Saves the node database into the DHT. Call this periodically or just before stopping the DHT.
// The current Node ID and port number are also saved.
func (ds *DHTStorage) SaveDHT(d *dht.DHT) error {
db, err := ds.getDB()
if err != nil {
return err
}
defer db.Close()
now := time.Now()
err = ds.createTablesWith(db)
if err != nil {
return err
}
tx, err := db.Begin()
if err != nil {
return err
}
_, err = tx.Exec(`UPDATE dht_routers SET old=1;`)
if err != nil {
return err
}
err = d.VisitNodes(func(addr string, nodeID []byte) error {
_, err := tx.Exec(`INSERT OR IGNORE INTO dht_routers
(hostname,first_seen,old) VALUES (?,?,0);`,
addr, now)
if err != nil {
return err
}
_, err = tx.Exec(`UPDATE dht_routers SET node_id=?, last_seen=?, old=0 WHERE hostname=?;`,
hex.EncodeToString(nodeID), now, addr)
if err != nil {
return err
}
return nil
})
if err != nil {
return err
}
_, err = tx.Exec(`DELETE FROM dht_routers WHERE old=1 AND last_seen < date('now','-2 hours');`)
if err != nil {
return err
}
_, err = tx.Exec(`UPDATE dht_routers SET first_seen=? WHERE first_seen IS NULL`, time.Now())
if err != nil {
return err
}
_, err = tx.Exec(`INSERT OR REPLACE INTO dht_settings (key,value) VALUES ('port',?)`, d.Port())
if err != nil {
return err
}
tx.Commit()
return nil
}