ethclient: add initial implementation of the typed RPC client
ethclient implements the proposed Ethereum Go API. There are no tests at the moment, a suite that excercises all implementations of the API will be added later.
This commit is contained in:
Felix Lange
parent
8d9141ed9a
commit
46621fd2c3
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// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package ethclient provides a client for the Ethereum RPC API.
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package ethclient
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import (
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"encoding/json"
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"fmt"
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"math/big"
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"github.com/ethereum/go-ethereum"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/core/vm"
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"github.com/ethereum/go-ethereum/rlp"
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"github.com/ethereum/go-ethereum/rpc"
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"golang.org/x/net/context"
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)
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// Client defines typed wrappers for the Ethereum RPC API.
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type Client struct {
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c *rpc.Client
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}
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// Dial connects a client to the given URL.
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func Dial(rawurl string) (*Client, error) {
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c, err := rpc.Dial(rawurl)
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if err != nil {
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return nil, err
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}
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return NewClient(c), nil
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}
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// NewClient creates a client that uses the given RPC client.
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func NewClient(c *rpc.Client) *Client {
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return &Client{c}
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}
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// Blockchain Access
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// BlockByHash returns the given full block.
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//
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// Note that loading full blocks requires two requests. Use HeaderByHash
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// if you don't need all transactions or uncle headers.
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func (ec *Client) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
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return ec.getBlock(ctx, "eth_getBlockByHash", hash, true)
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}
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// BlockByNumber returns a block from the current canonical chain. If number is nil, the
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// latest known block is returned.
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//
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// Note that loading full blocks requires two requests. Use HeaderByNumber
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// if you don't need all transactions or uncle headers.
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func (ec *Client) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
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return ec.getBlock(ctx, "eth_getBlockByNumber", toBlockNumArg(number), true)
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}
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type rpcBlock struct {
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Hash common.Hash `json:"hash"`
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Transactions []*types.Transaction `json:"transactions"`
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UncleHashes []common.Hash `json:"uncles"`
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}
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func (ec *Client) getBlock(ctx context.Context, method string, args ...interface{}) (*types.Block, error) {
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var raw json.RawMessage
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err := ec.c.CallContext(ctx, &raw, method, args...)
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if err != nil {
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return nil, err
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}
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// Decode header and transactions.
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var head *types.Header
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var body rpcBlock
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if err := json.Unmarshal(raw, &head); err != nil {
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return nil, err
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}
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if err := json.Unmarshal(raw, &body); err != nil {
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return nil, err
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}
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// Quick-verify transaction and uncle lists. This mostly helps with debugging the server.
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if head.UncleHash == types.EmptyUncleHash && len(body.UncleHashes) > 0 {
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return nil, fmt.Errorf("server returned non-empty uncle list but block header indicates no uncles")
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}
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if head.UncleHash != types.EmptyUncleHash && len(body.UncleHashes) == 0 {
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return nil, fmt.Errorf("server returned empty uncle list but block header indicates uncles")
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}
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if head.TxHash == types.EmptyRootHash && len(body.Transactions) > 0 {
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return nil, fmt.Errorf("server returned non-empty transaction list but block header indicates no transactions")
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}
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if head.TxHash != types.EmptyRootHash && len(body.Transactions) == 0 {
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return nil, fmt.Errorf("server returned empty transaction list but block header indicates transactions")
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}
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// Load uncles because they are not included in the block response.
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var uncles []*types.Header
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if len(body.UncleHashes) > 0 {
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uncles = make([]*types.Header, len(body.UncleHashes))
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reqs := make([]rpc.BatchElem, len(body.UncleHashes))
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for i := range reqs {
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reqs[i] = rpc.BatchElem{
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Method: "eth_getUncleByBlockHashAndIndex",
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Args: []interface{}{body.Hash, fmt.Sprintf("%#x", i)},
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Result: &uncles[i],
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}
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}
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if err := ec.c.BatchCallContext(ctx, reqs); err != nil {
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return nil, err
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}
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for i := range reqs {
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if reqs[i].Error != nil {
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return nil, reqs[i].Error
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}
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}
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}
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return types.NewBlockWithHeader(head).WithBody(body.Transactions, uncles), nil
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}
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// HeaderByHash returns the block header with the given hash.
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func (ec *Client) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
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var head *types.Header
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err := ec.c.CallContext(ctx, &head, "eth_getBlockByHash", hash, false)
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return head, err
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}
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// HeaderByNumber returns a block header from the current canonical chain. If number is
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// nil, the latest known header is returned.
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func (ec *Client) HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error) {
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var head *types.Header
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err := ec.c.CallContext(ctx, &head, "eth_getBlockByNumber", toBlockNumArg(number), false)
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return head, err
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}
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// TransactionByHash returns the transaction with the given hash.
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func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (*types.Transaction, error) {
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var tx *types.Transaction
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err := ec.c.CallContext(ctx, &tx, "eth_getTransactionByHash", hash, false)
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if err == nil {
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if _, r, _ := tx.SignatureValues(); r == nil {
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return nil, fmt.Errorf("server returned transaction without signature")
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}
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}
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return tx, err
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}
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// TransactionCount returns the total number of transactions in the given block.
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func (ec *Client) TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error) {
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var num rpc.HexNumber
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err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByHash", blockHash)
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return num.Uint(), err
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}
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// TransactionInBlock returns a single transaction at index in the given block.
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func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
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var tx *types.Transaction
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err := ec.c.CallContext(ctx, &tx, "eth_getTransactionByBlockHashAndIndex", blockHash, index)
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if err == nil {
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if _, r, _ := tx.SignatureValues(); r == nil {
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return nil, fmt.Errorf("server returned transaction without signature")
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}
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}
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return tx, err
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}
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// TransactionReceipt returns the receipt of a transaction by transaction hash.
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// Note that the receipt is not available for pending transactions.
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func (ec *Client) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
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var r *types.Receipt
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err := ec.c.CallContext(ctx, &r, "eth_getTransactionReceipt", txHash)
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if err == nil && r != nil && len(r.PostState) == 0 {
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return nil, fmt.Errorf("server returned receipt without post state")
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}
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return r, err
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}
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func toBlockNumArg(number *big.Int) string {
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if number == nil {
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return "latest"
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}
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return fmt.Sprintf("%#x", number)
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}
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// SubscribeNewHead subscribes to notifications about the current blockchain head
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// on the given channel.
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func (ec *Client) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (ethereum.Subscription, error) {
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return ec.c.EthSubscribe(ctx, ch, "newBlocks", map[string]struct{}{})
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}
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// State Access
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// BalanceAt returns the wei balance of the given account.
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// The block number can be nil, in which case the balance is taken from the latest known block.
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func (ec *Client) BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error) {
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var result rpc.HexNumber
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err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, toBlockNumArg(blockNumber))
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return (*big.Int)(&result), err
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}
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// StorageAt returns the value of key in the contract storage of the given account.
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// The block number can be nil, in which case the value is taken from the latest known block.
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func (ec *Client) StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
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var result rpc.HexBytes
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err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, toBlockNumArg(blockNumber))
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return result, err
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}
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// CodeAt returns the contract code of the given account.
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// The block number can be nil, in which case the code is taken from the latest known block.
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func (ec *Client) CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error) {
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var result rpc.HexBytes
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err := ec.c.CallContext(ctx, &result, "eth_getCode", account, toBlockNumArg(blockNumber))
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return result, err
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}
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// NonceAt returns the account nonce of the given account.
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// The block number can be nil, in which case the nonce is taken from the latest known block.
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func (ec *Client) NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error) {
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var result rpc.HexNumber
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err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, toBlockNumArg(blockNumber))
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return result.Uint64(), err
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}
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// Filters
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// FilterLogs executes a filter query.
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func (ec *Client) FilterLogs(ctx context.Context, q ethereum.FilterQuery) ([]vm.Log, error) {
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var result []vm.Log
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err := ec.c.CallContext(ctx, &result, "eth_getFilterLogs", toFilterArg(q))
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return result, err
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}
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// SubscribeFilterLogs subscribes to the results of a streaming filter query.
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func (ec *Client) SubscribeFilterLogs(ctx context.Context, q ethereum.FilterQuery, ch chan<- vm.Log) (ethereum.Subscription, error) {
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return ec.c.EthSubscribe(ctx, ch, "logs", toFilterArg(q))
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}
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func toFilterArg(q ethereum.FilterQuery) interface{} {
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arg := map[string]interface{}{
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"fromBlock": toBlockNumArg(q.FromBlock),
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"endBlock": toBlockNumArg(q.ToBlock),
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"addresses": q.Addresses,
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"topics": q.Topics,
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}
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if q.FromBlock == nil {
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arg["fromBlock"] = "0x0"
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}
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return arg
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}
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// Pending State
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// PendingBalanceAt returns the wei balance of the given account in the pending state.
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func (ec *Client) PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error) {
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var result rpc.HexNumber
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err := ec.c.CallContext(ctx, &result, "eth_getBalance", account, "pending")
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return (*big.Int)(&result), err
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}
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// PendingStorageAt returns the value of key in the contract storage of the given account in the pending state.
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func (ec *Client) PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error) {
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var result rpc.HexBytes
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err := ec.c.CallContext(ctx, &result, "eth_getStorageAt", account, key, "pending")
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return result, err
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}
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// PendingCodeAt returns the contract code of the given account in the pending state.
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func (ec *Client) PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error) {
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var result rpc.HexBytes
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err := ec.c.CallContext(ctx, &result, "eth_getCode", account, "pending")
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return result, err
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}
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// PendingNonceAt returns the account nonce of the given account in the pending state.
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// This is the nonce that should be used for the next transaction.
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func (ec *Client) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
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var result rpc.HexNumber
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err := ec.c.CallContext(ctx, &result, "eth_getTransactionCount", account, "pending")
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return result.Uint64(), err
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}
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// PendingTransactionCount returns the total number of transactions in the pending state.
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func (ec *Client) PendingTransactionCount(ctx context.Context) (uint, error) {
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var num rpc.HexNumber
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err := ec.c.CallContext(ctx, &num, "eth_getBlockTransactionCountByNumber", "pending")
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return num.Uint(), err
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}
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// TODO: SubscribePendingTransactions (needs server side)
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// Contract Calling
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// CallContract executes a message call transaction, which is directly executed in the VM
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// of the node, but never mined into the blockchain.
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//
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// blockNumber selects the block height at which the call runs. It can be nil, in which
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// case the code is taken from the latest known block. Note that state from very old
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// blocks might not be available.
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func (ec *Client) CallContract(ctx context.Context, msg ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
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var hex string
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err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), toBlockNumArg(blockNumber))
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if err != nil {
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return nil, err
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}
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return common.FromHex(hex), nil
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}
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// PendingCallContract executes a message call transaction using the EVM.
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// The state seen by the contract call is the pending state.
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func (ec *Client) PendingCallContract(ctx context.Context, msg ethereum.CallMsg) ([]byte, error) {
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var hex string
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err := ec.c.CallContext(ctx, &hex, "eth_call", toCallArg(msg), "pending")
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if err != nil {
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return nil, err
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}
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return common.FromHex(hex), nil
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}
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// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
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// execution of a transaction.
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func (ec *Client) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
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var hex rpc.HexNumber
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if err := ec.c.CallContext(ctx, &hex, "eth_gasPrice"); err != nil {
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return nil, err
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}
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return (*big.Int)(&hex), nil
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}
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// EstimateGas tries to estimate the gas needed to execute a specific transaction based on
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// the current pending state of the backend blockchain. There is no guarantee that this is
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// the true gas limit requirement as other transactions may be added or removed by miners,
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// but it should provide a basis for setting a reasonable default.
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func (ec *Client) EstimateGas(ctx context.Context, msg ethereum.CallMsg) (*big.Int, error) {
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var hex rpc.HexNumber
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err := ec.c.CallContext(ctx, &hex, "eth_estimateGas", toCallArg(msg))
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if err != nil {
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return nil, err
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}
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return (*big.Int)(&hex), nil
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}
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// SendTransaction injects a signed transaction into the pending pool for execution.
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//
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// If the transaction was a contract creation use the TransactionReceipt method to get the
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// contract address after the transaction has been mined.
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func (ec *Client) SendTransaction(ctx context.Context, tx *types.Transaction) error {
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data, err := rlp.EncodeToBytes(tx)
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if err != nil {
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return err
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}
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return ec.c.CallContext(ctx, nil, "eth_sendRawTransaction", common.ToHex(data))
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}
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func toCallArg(msg ethereum.CallMsg) interface{} {
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arg := map[string]interface{}{
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"from": msg.From,
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"to": msg.To,
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}
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if len(msg.Data) > 0 {
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arg["data"] = fmt.Sprintf("%#x", msg.Data)
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}
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if msg.Value != nil {
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arg["value"] = fmt.Sprintf("%#x", msg.Value)
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}
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if msg.Gas != nil {
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arg["gas"] = fmt.Sprintf("%#x", msg.Gas)
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}
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if msg.GasPrice != nil {
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arg["gasPrice"] = fmt.Sprintf("%#x", msg.GasPrice)
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}
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return arg
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}
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@ -0,0 +1,17 @@
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package ethclient
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import "github.com/ethereum/go-ethereum"
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// Verify that Client implements the ethereum interfaces.
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var (
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_ = ethereum.ChainReader(&Client{})
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_ = ethereum.ChainStateReader(&Client{})
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_ = ethereum.ChainHeadEventer(&Client{})
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_ = ethereum.ContractCaller(&Client{})
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_ = ethereum.GasEstimator(&Client{})
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_ = ethereum.GasPricer(&Client{})
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_ = ethereum.LogFilterer(&Client{})
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_ = ethereum.PendingStateReader(&Client{})
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// _ = ethereum.PendingStateEventer(&Client{})
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_ = ethereum.PendingContractCaller(&Client{})
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)
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