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A simple golang script to parse the ffldb database files created by btcd.
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package main | |
import ( | |
"encoding/binary" | |
"flag" | |
"fmt" | |
_ "github.com/btcsuite/btcd/database/ffldb" | |
"github.com/btcsuite/btcd/chaincfg/chainhash" | |
"github.com/btcsuite/btcd/database" | |
"github.com/btcsuite/btcd/wire" | |
"github.com/btcsuite/btcutil" | |
) | |
func main() { | |
dbPath := flag.String( | |
"dbpath", | |
"/home/ubuntu/.btcd/mainnet/blocks_ffldb", | |
"the btcd blocks ffldb file path", | |
) | |
startHeight := flag.Int( | |
"start", 0, "specify the blocks starting height", | |
) | |
endHeight := flag.Int( | |
"end", 0, "specify the blocks ending height. inclusive", | |
) | |
flag.Parse() | |
blocks, err := FetchBlocks( | |
*dbPath, int32(*startHeight), int32(*endHeight), | |
) | |
if err != nil { | |
fmt.Println(err) | |
return | |
} | |
for _, b := range blocks { | |
fmt.Printf("found %v\n", b.Height()) | |
} | |
fmt.Printf("found %v blocks\n", len(blocks)) | |
} | |
var ( | |
// heightIndexBucketName is the name of the db bucket used to house to | |
// the block height -> block hash index. | |
heightIndexBucketName = []byte("heightidx") | |
) | |
// FetchBlocks opens the database and parses the blocks. | |
func FetchBlocks(dbPath string, start, end int32) ([]*btcutil.Block, error) { | |
// load btcd db file | |
db, err := database.Open("ffldb", dbPath, wire.MainNet) | |
if err != nil { | |
return nil, err | |
} | |
defer db.Close() | |
return dbFetchBlocks(db, start, end) | |
} | |
func dbFetchBlocks(db database.DB, start, end int32) ([]*btcutil.Block, error) { | |
var blocks []*btcutil.Block | |
var err error | |
err = db.View(func(tx database.Tx) error { | |
blocks, err = bulkFetchBlocks(tx, start, end) | |
return err | |
}) | |
if err != nil { | |
return nil, err | |
} | |
return blocks, nil | |
} | |
// bulkFetchBlocks uses an existing database bucket to retrieve a | |
// collection of block hashes for the provided height range. | |
// Note that the start and end values are inclusive. For instance, start=0, | |
// end=10 will fetch for block 0 till block 10, a total of 11 blocks. | |
func bulkFetchBlocks(tx database.Tx, | |
start, end int32) ([]*btcutil.Block, error) { | |
meta := tx.Metadata() | |
heightIndexBucket := meta.Bucket(heightIndexBucketName) | |
// make a slice to avoid copy | |
blocks := make([]*btcutil.Block, end-start+1) | |
// fetchHash is a closure to fetch block hash by a given height. | |
fetchHash := func(height int32) (*chainhash.Hash, error) { | |
var serializedHeight [4]byte | |
binary.LittleEndian.PutUint32( | |
serializedHeight[:], uint32(height), | |
) | |
hashBytes := heightIndexBucket.Get(serializedHeight[:]) | |
if hashBytes == nil { | |
return nil, fmt.Errorf( | |
"no block at height %d exists", height, | |
) | |
} | |
var hash chainhash.Hash | |
copy(hash[:], hashBytes) | |
return &hash, nil | |
} | |
fetchBlock := func(hash *chainhash.Hash) (*btcutil.Block, error) { | |
// Use the View function of the database to perform a managed | |
// read-only transaction and fetch the block stored. | |
blockBytes, err := tx.FetchBlock(hash) | |
if err != nil { | |
return nil, err | |
} | |
block, err := btcutil.NewBlockFromBytes(blockBytes) | |
if err != nil { | |
return nil, err | |
} | |
return block, nil | |
} | |
for i := range blocks { | |
// Calculate the height and encode | |
height := start + int32(i) | |
hash, err := fetchHash(height) | |
if err != nil { | |
return nil, err | |
} | |
block, err := fetchBlock(hash) | |
if err != nil { | |
return nil, err | |
} | |
// assign the height | |
block.SetHeight(height) | |
blocks[i] = block | |
} | |
return blocks, nil | |
} |
Get the following error when running this on the testnet:
block data for block 683e86bd5c6d110d91b94b97137ba6bfe02dbbdb8e3dff722a669b5d69d77af6 is for the wrong network - got 303307798, want 3669344250
how can this script be changed to support test net?
Get the following error when running this on the testnet:
block data for block 683e86bd5c6d110d91b94b97137ba6bfe02dbbdb8e3dff722a669b5d69d77af6 is for the wrong network - got 303307798, want 3669344250
how can this script be changed to support test net?
I think you only need to point the dbpath
to your testnet files, not mainnet/blocks_ffldb
but testnet/blocks_ffldb
.
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For instance, the following command will parse the block height from 0 to 9, a total of 10 blocks.