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How to store + decode objects in golang using leveldb + gob
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package main | |
import ( | |
"bytes" | |
"encoding/gob" | |
"fmt" | |
"time" | |
"github.com/syndtr/goleveldb/leveldb" | |
) | |
type Node struct { | |
id string | |
body string | |
CreatedAt time.Time | |
UpdatedAt time.Time | |
} | |
var ( | |
NodeStorage *leveldb.DB | |
NodeMemory = make(map[string]*Node) | |
) | |
func main() { | |
var err error | |
NodeStorage, err = leveldb.OpenFile("level", nil) | |
if err != nil { | |
fmt.Println(err.Error()) | |
return | |
} | |
now := time.Now() | |
n := Node{"42", "body", now, now} | |
err = n.Save() | |
if err != nil { | |
fmt.Println(err.Error()) | |
return | |
} | |
nn, err := FindNode("42") | |
nn.body = "another body" | |
nn.Save() | |
nn2, err := FindNode("42") | |
fmt.Println(nn2) | |
} | |
func FindNode(nodeId string) (node *Node, err error) { | |
node, inMem := NodeMemory[nodeId] | |
if !inMem { | |
var data []byte | |
data, err = NodeStorage.Get([]byte(nodeId), nil) | |
if err != nil { | |
return | |
} | |
dec := gob.NewDecoder(bytes.NewReader(data)) | |
dec.Decode(node) | |
} | |
return | |
} | |
func (n *Node) Delete() (node Node, err error) { | |
err = NodeStorage.Delete([]byte(n.id), nil) | |
if err != nil { | |
return | |
} | |
delete(NodeMemory, n.id) | |
node = *n | |
return | |
} | |
func (n *Node) Save() (err error) { | |
n.UpdatedAt = time.Now() | |
var data bytes.Buffer | |
enc := gob.NewEncoder(&data) | |
enc.Encode(*n) | |
err = NodeStorage.Put([]byte(n.id), data.Bytes(), nil) | |
if err != nil { | |
return | |
} | |
if _, inMemory := NodeMemory[n.id]; !inMemory { | |
NodeMemory[n.id] = n | |
} | |
return | |
} |
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dec.Decode(node)
should be written asdec.Decode(&node)