[Back] We can use Go to access the Ethereum blocks. The following shows the details of the first five transactions in a given bloc:
Ethereum Block in Go |
Theory
package main
import (
"context"
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/ethclient"
"strconv"
"os"
)
func main() {
argCount := len(os.Args[1:])
client, _ := ethclient.Dial("https://mainnet.infura.io")
header, _ := client.HeaderByNumber(context.Background(), nil)
fmt.Printf("Current block: %s\n\n",header.Number.String())
blk:="1"
b,_:=strconv.ParseInt(blk, 10, 64)
if argCount>0 {
blk=os.Args[1]
b,_=strconv.ParseInt(blk, 10, 64)
}
if argCount==0 {
b,_=strconv.ParseInt(header.Number.String(), 10, 64)
}
fmt.Printf("Target block: %d\n",b)
blockNumber := big.NewInt(b)
block, _ := client.BlockByNumber(context.Background(), blockNumber)
i:=0
fmt.Printf("Listing the first five transactions ...\n\n")
for _, tx := range block.Transactions() {
fmt.Printf("Hash: %s\n",tx.Hash().Hex())
fmt.Printf("Value: %s\n",tx.Value().String())
fmt.Printf("Gas: %d\n",tx.Gas())
fmt.Printf("Gas price: %d\n",tx.GasPrice().Uint64())
fmt.Printf("Nonce: %d\n",tx.Nonce())
fmt.Printf("Tx: %s\n",tx.Data())
fmt.Printf("Tx: %s\n\n",tx.To().Hex())
i++
if (i>5) { break }
}
}
A sample run is:
Current block: 8001550 Target block: 8001550 Listing the first five transactions ... Hash: 0x0af855730aefbe90b29c22c9baa3deededdde56e008ce91b5c90b6dcea221f98 Value: 0 Gas: 120000 Gas price: 50000000000 Nonce: 31 Tx: ©œ»������������U±˜ˆ¾ÌɧÞEœOq».æ����������������������åš©KŒ D7¨� Tx: 0x8290333ceF9e6D528dD5618Fb97a76f268f3EDD4 Hash: 0x804d77148a44e41cd612033456afee631b9c178d4738b30279be37c3a8ddce40 Value: 0 Gas: 4300000 Gas price: 42000000000 Nonce: 24325 Tx: ©œ»������������Ï”ÀÉÖãa´d™0Ic�‚¨ í����������������������������Í)À Tx: 0xd0929d411954c47438dc1d871dd6081F5C5e149c Hash: 0x6e475b1b7336aebc28abd9ab15dc91838849aa2faf79b74b89caf08a45aa316f Value: 24488163890000000000 Gas: 90000 Gas price: 40000000000 Nonce: 120921 Tx: Tx: 0x104C42fDe4b9DF8761CDabEb2bd890C650c2bC24 Hash: 0x9ff35bf9ecb8a3f323f6011b022fa96dcb3303a3171fd3e63e07822e6b28d23e Value: 0 Gas: 106294 Gas price: 40000000000 Nonce: 1500977 Tx: ©œ»������������§Åñ)íC¡YÍÙò\o”ŸÀ]p�����������������������‘ ÷%W÷€� Tx: 0x1D287CC25dAD7cCaF76a26bc660c5F7C8E2a05BD Hash: 0x04651e0e2632f00b99731b6ee4e0bff872b86f3a1fb9c783d601f93e6ecd1bdc Value: 2595000000000000000 Gas: 90000 Gas price: 22900000000 Nonce: 80290 Tx: Tx: 0x52C9869e491AB3345480bd720382F31bF9dACbbC Hash: 0x72c4cd980f57c8d1090a978705870f7fed5159bff3b318d7ede46fce94165f3f Value: 2503252000000000000 Gas: 90000 Gas price: 22900000000 Nonce: 403902 Tx: Tx: 0xbd8D2dB142e1b34D944aC578693BE0d890e314a8