skeleton repl

main.go

package main

import (
    "bufio"
    "fmt"
    "log"
    "os"
    "strings"

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

func main() {
    // Connect to the Ethereum network
    client, err := ethclient.Dial("https://ropsten.infura.io/v3/YOUR-PROJECT-ID")
    if err != nil {
        log.Fatal(err)
    }

    // Load the contract
    contractAbi, err := abi.JSON(strings.NewReader(string(contractABI)))
    if err != nil {
        log.Fatal(err)
    }

    contractAddress := common.HexToAddress("...")

    // Create an instance of the contract
    contract, err := bind.NewBoundContract(contractAddress, contractAbi, client, client, client)
    if err != nil {
        log.Fatal(err)
    }

    // Start REPL
    reader := bufio.NewReader(os.Stdin)
    for {
        fmt.Print("> ")
        input, err := reader.ReadString('\n')
        if err != nil {
            log.Fatal(err)
        }

        // Remove new line character from input
        input = strings.TrimSpace(input)

        // Call function on contract
        switch input {
        case "getNumber":
            number, err := contract.GetNumber(nil)
            if err != nil {
                fmt.Println(err)
            } else {
                fmt.Println(number)
            }
        case "setNumber":
            fmt.Print("Enter new number: ")
            newNumber, err := reader.ReadString('\n')
            if err != nil {
                log.Fatal(err)
            }
            newNumber = strings.TrimSpace(newNumber)

            tx, err := contract.SetNumber(nil, newNumber)
            if err != nil {
                fmt.Println(err)
            } else {
                fmt.Println("Transaction hash:", tx.Hash().Hex())
            }
        case "exit":
            os.Exit(0)
        default:
            fmt.Println("Invalid command")
        }
    }
}