24writeContract.go

package main

import (
	"context"
	"crypto/ecdsa"
	"fmt"
	"github.com/ethereum/go-ethereum/crypto"
	"log"
	"math/big"
	"os"

	"github.com/ethereum/go-ethereum/accounts/abi/bind"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/ethclient"

	store "github.com/crazygit/ethereum-development-with-go-book-code/contracts"
)

func main() {
	client, err := ethclient.Dial("https://ropsten.infura.io/v3/28d5693e8bee4b58a61f0c627d62331e")
	if err != nil {
		log.Fatal(err)
	}

	privateKey, err := crypto.HexToECDSA(os.Getenv("PRIVATE_KEY"))
	if err != nil {
		log.Fatal(err)
	}

	publicKey := privateKey.Public()
	publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
	if !ok {
		log.Fatal("cannot assert type: publicKey is not of type *ecdsa.PublicKey")
	}

	fromAddress := crypto.PubkeyToAddress(*publicKeyECDSA)
	nonce, err := client.PendingNonceAt(context.Background(), fromAddress)
	if err != nil {
		log.Fatal(err)
	}

	gasPrice, err := client.SuggestGasPrice(context.Background())
	if err != nil {
		log.Fatal(err)
	}
	chainID, err := client.ChainID(context.Background())
	if err != nil {
		log.Fatal(err)
	}
	auth, err := bind.NewKeyedTransactorWithChainID(privateKey, chainID)
	auth.Nonce = big.NewInt(int64(nonce))
	auth.Value = big.NewInt(0)      // in wei
	auth.GasLimit = uint64(1000000) // in units
	auth.GasPrice = gasPrice

	// 部署的合约地址
	address := common.HexToAddress("0xDe348Ff064D244e6b983B9198E0bFbb9D4C5CD69")
	instance, err := store.NewStore(address, client)
	if err != nil {
		log.Fatal(err)
	}

	key := [32]byte{}
	value := [32]byte{}
	copy(key[:], "foo")
	copy(value[:], "bar")

	tx, err := instance.SetItem(auth, key, value)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("tx sent: %s\n", tx.Hash().Hex())

	result, err := instance.Items(nil, key)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(string(result[:])) // "bar"
}