induzo/gostorage

package ethereum

import (
    "context"
    "fmt"

    "github.com/ethereum/go-ethereum/ethclient"
)

// Config is a conf for the ethereum node
type Config struct {
    Host            string
    JSONRPCPort     string
    JSONRPCProtocol string
    WSProtocol      string
    WSPort          string
    NetworkID       int64
}

// NewRPCCli connects to ethereum node and return a connection backend
func NewRPCCli(ethConf Config) (*ethclient.Client, error) {
    cli, err := ethclient.Dial(
        ethConf.JSONRPCProtocol +
            "://" + ethConf.Host +
            ":" + ethConf.JSONRPCPort,
    )
    if err != nil {
        return nil, fmt.Errorf("NewRPCCli: rpc.Dial %v", err)
    }

    networkID, errNID := cli.NetworkID(context.Background())
    if errNID != nil {
        return nil, fmt.Errorf("NewRPCCli: NetworkID %v", errNID)
    }

    if networkID.Int64() != ethConf.NetworkID {
        return nil,
            fmt.Errorf(
                "NewRPCCli: NetworkID %d "+
                    "different from wanted NetworkID %d",
                networkID, ethConf.NetworkID,
            )
    }

    return cli, nil
}

// NewWSCli connects to ethereum node and return a connection backend
func NewWSCli(ethConf Config) (*ethclient.Client, error) {
    cli, err := ethclient.Dial(
        ethConf.WSProtocol +
            "://" + ethConf.Host +
            ":" + ethConf.WSPort,
    )
    if err != nil {
        return nil, fmt.Errorf("NewWSCli: rpc.Dial %v", err)
    }

    networkID, errNID := cli.NetworkID(context.Background())
    if errNID != nil {
        return nil, fmt.Errorf("NewWSCli: NetworkID %v", errNID)
    }

    if networkID.Int64() != ethConf.NetworkID {
        return nil,
            fmt.Errorf(
                "NewWSCli: NetworkID %d "+
                    "different from wanted NetworkID %d",
                networkID, ethConf.NetworkID,
            )
    }

    return cli, nil
}