path: root/ethclient/ethclient.go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

// Package ethclient provides a client for the Ethereum RPC API.
package ethclient

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"math/big"

	"github.com/ava-labs/avalanchego/ids"
	"github.com/ava-labs/coreth"
	"github.com/ava-labs/coreth/core/types"
	"github.com/ava-labs/coreth/rpc"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/rlp"
)

// Client defines typed wrappers for the Ethereum RPC API.
type Client struct {
	c *rpc.Client
}

// Dial connects a client to the given URL.
func Dial(rawurl string) (*Client, error) {
	return DialContext(context.Background(), rawurl)
}

func DialContext(ctx context.Context, rawurl string) (*Client, error) {
	c, err := rpc.DialContext(ctx, rawurl)
	if err != nil {
		return nil, err
	}
	return NewClient(c), nil
}

// NewClient creates a client that uses the given RPC client.
func NewClient(c *rpc.Client) *Client {
	return &Client{c}
}

func (ec *Client) Close() {
	ec.c.Close()
}

// Blockchain Access

// ChainId retrieves the current chain ID for transaction replay protection.
func (ec *Client) ChainID(ctx context.Context) (*big.Int, error) {
	var result hexutil.Big
	err := ec.c.CallContext(ctx, &result, "eth_chainId")
	if err != nil {
		return nil, err
	}
	return (*big.Int)(&result), err
}

// BlockByHash returns the given full block.
//
// Note that loading full blocks requires two requests. Use HeaderByHash
// if you don't need all transactions or uncle headers.
func (ec *Client) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
	return ec.getBlock(ctx, "eth_getBlockByHash", hash, true)
}

// BlockByNumber returns a block from the current canonical chain. If number is nil, the
// latest known block is returned.
//
// Note that loading full blocks requires two requests. Use HeaderByNumber
// if you don't need all transactions or uncle headers.
func (ec *Client) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
	return ec.getBlock(ctx, "eth_getBlockByNumber", toBlockNumArg(number), true)
}

// BlockNumber returns the most recent block number
func (ec *Client) BlockNumber(ctx context.Context) (uint64, error) {
	var result hexutil.Uint64
	err := ec.c.CallContext(ctx, &result, "eth_blockNumber")
	return uint64(result), err
}

type rpcBlock struct {
	Hash           common.Hash      `json:"hash"`
	Transactions   []rpcTransaction `json:"transactions"`
	UncleHashes    []common.Hash    `json:"uncles"`
	Version        uint32           `json:"version"`
	BlockExtraData string           `json:"blockExtraData"`
}

func (ec *Client) getBlock(ctx context.Context, method string, args ...interface{}) (*types.Block, error) {
	var raw json.RawMessage
	err := ec.c.CallContext(ctx, &raw, method, args...)
	if err != nil {
		return nil, err
	} else if len(raw) == 0 {
		return nil, coreth.NotFound
	}
	// Decode header and transactions.
	var head *types.Header
	var body rpcBlock
	if err := json.Unmarshal(raw, &head); err != nil {
		return nil, err
	}
	if err := json.Unmarshal(raw, &body); err != nil {
		return nil, err
	}

	var blockExtraData *[]byte
	if len(body.BlockExtraData) != 0 {
		blockExtraDataDecoded, err := hexutil.Decode(body.BlockExtraData)
		if err != nil {
			return nil, fmt.Errorf("problem parsing block extra data: %w", err)
		}
		blockExtraData = &blockExtraDataDecoded
	}

	// Quick-verify transaction and uncle lists. This mostly helps with debugging the server.
	if head.UncleHash == types.EmptyUncleHash && len(body.UncleHashes) > 0 {
		return nil, fmt.Errorf("server returned non-empty uncle list but block header indicates no uncles")
	}
	if head.UncleHash != types.EmptyUncleHash && len(body.UncleHashes) == 0 {
		return nil, fmt.Errorf("server returned empty uncle list but block header indicates uncles")
	}
	if head.TxHash == types.EmptyRootHash && len(body.Transactions) > 0 {
		return nil, fmt.Errorf("server returned non-empty transaction list but block header indicates no transactions")
	}
	if head.TxHash != types.EmptyRootHash && len(body.Transactions) == 0 {
		return nil, fmt.Errorf("server returned empty transaction list but block header indicates transactions")
	}
	// Load uncles because they are not included in the block response.
	var uncles []*types.Header
	if len(body.UncleHashes) > 0 {
		uncles = make([]*types.Header, len(body.UncleHashes))
		reqs := make([]rpc.BatchElem, len(body.UncleHashes))
		for i := range reqs {
			reqs[i] = rpc.BatchElem{
				Method: "eth_getUncleByBlockHashAndIndex",
				Args:   []interface{}{body.Hash, hexutil.EncodeUint64(uint64(i))},
				Result: &uncles[i],
			}
		}