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package main
import (
var (
headerPrefix = []byte("h") // headerPrefix + num (uint64 big endian) + hash -> header
numSuffix = []byte("n") // headerPrefix + num (uint64 big endian) + numSuffix -> hash
func main() {
// Connection to leveldb
db, _ := leveldb.OpenFile("/home/kara/.ethereum/geth/chaindata", nil)
// 40 to bytes (Big endian)
blockNumber := make([]byte, 8)
binary.BigEndian.PutUint64(blockNumber, uint64(40))
fmt.Printf("Details of Blocknumber:- \nHex: %x \nBytes: %d\n\n\n", blockNumber, blockNumber)
// create key to get hash (headerPrefix + num (uint64 big endian) + numSuffix)
hashKey := append(headerPrefix, blockNumber...) // adding prefix
hashKey = append(hashKey, numSuffix...) // adding suffix
fmt.Printf("Details of leveldb key for Block Hash:- \nType: %T \nHex: %x \nbytes: %v \nLength: %d\n\n\n", hashKey,hashKey,hashKey, len(hashKey))
// Getting hash using hashKey
blockHash, _ := db.Get(hashKey, nil)
fmt.Printf("Details of Block hash:- \nType: %T \nHex: %x \nBytes: %v\n\n\n", blockHash, blockHash,blockHash)
//Create key to get header (headerPrefix + num (uint64 big endian) + hash)
headerKey := append(headerPrefix, blockNumber...) // adding prefix
headerKey = append(headerKey, blockHash...) // adding suffix
fmt.Printf("Details of leveldb key for Block Header:- \nType: %T \nHex: %x \nVytes: %v \nLength: %d\n\n\n", headerKey,headerKey,headerKey, len(headerKey))
//get Block Header data from db
blockHeaderData, _ := db.Get(headerKey, nil)
fmt.Printf("Details of Raw Block Header:- \nType: %T \nHex: %x \nBytes: %v \nLength: %d\n\n\n", blockHeaderData,blockHeaderData,blockHeaderData, len(blockHeaderData))
//new Blockheader type
blockHeader := new(types.Header)
fmt.Printf("Details of new Header Type:- \nType: %T \nHex: %x \nValue: %v\n\n\n", blockHeader,blockHeader,blockHeader)
// Read blockHeaderData in a tmp variable
tmpByteData := bytes.NewReader(blockHeaderData)
fmt.Printf("Details of tmpByteData:- \nType: %T \nHex: %x \nValue: %v\n\n\n", tmpByteData,tmpByteData,tmpByteData)
//Decode tmpByteData to new blockHeader
rlp.Decode(tmpByteData, blockHeader)
fmt.Printf("Details of Header for block number 40:- \nType: %T \nHex: %x \nValue: %v\n\n\n", blockHeader,blockHeader,blockHeader)
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