ipld-eth-server/pkg/geth/contract.go

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// VulcanizeDB
// Copyright © 2018 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package geth
import (
"errors"
"context"
"math/big"
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/common"
)
var (
ErrInvalidStateAttribute = errors.New("invalid state attribute")
)
func (blockChain *BlockChain) FetchContractData(abiJSON string, address string, method string, methodArgs []interface{}, result interface{}, blockNumber int64) error {
parsed, err := ParseAbi(abiJSON)
if err != nil {
return err
}
var input []byte
if methodArgs != nil {
input, err = parsed.Pack(method, methodArgs...)
} else {
input, err = parsed.Pack(method)
}
if err != nil {
return err
}
output, err := blockChain.callContract(address, input, big.NewInt(blockNumber))
if err != nil {
return err
}
return parsed.Unpack(result, method, output)
}
func (blockChain *BlockChain) callContract(contractHash string, input []byte, blockNumber *big.Int) ([]byte, error) {
to := common.HexToAddress(contractHash)
msg := ethereum.CallMsg{To: &to, Data: input}
return blockChain.client.CallContract(context.Background(), msg, blockNumber)
}