init: PoC

* only supports legacy transactions

pkg/block/block.go

@@ -0,0 +1,40 @@
+package block
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+)
+
+type FetchResponse struct {
+	Block             MinimalBlock         `json:"block"`
+	TransactionsCount int                  `json:"transactionsCount"`
+	Transactions      []MinimalTransaction `json:"transactions"`
+}
+
+type MinimalBlock struct {
+	Hash     common.Hash `json:"hash"`
+	Number   *big.Int    `json:"number"`
+	Bloom    types.Bloom `json:"logsBloom"`
+	GasLimit uint64      `json:"gasLimit"`
+	GasUsed  uint64      `json:"gasUsed"`
+	Time     uint64      `json:"timestamp"`
+}
+
+type MinimalTransaction struct {
+	Hash             common.Hash     `json:"hash"`
+	From             common.Address  `json:"from"`
+	To               *common.Address `json:"to"`
+	Gas              uint64          `json:"gas"`
+	GasPrice         *big.Int        `json:"gasPrice"`
+	Nonce            uint64          `json:"nonce"`
+	Value            *big.Int        `json:"value"`
+	InputData        string          `json:"input"`
+	TransactionIndex uint            `json:"transactionIndex"`
+	Status           uint64          `json:"status"`
+	GasUsed          uint64          `json:"gasUsed"`
+	Bloom            types.Bloom     `json:"logsBloom"`
+	Logs             []*types.Log    `json:"logs"`
+	ContractAddress  common.Address  `json:"contractAddress"`
+}

pkg/block/fetch.go

@@ -0,0 +1,92 @@
+package block
+
+import (
+	"context"
+	"encoding/hex"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/lmittmann/w3"
+	"github.com/lmittmann/w3/module/eth"
+	"github.com/lmittmann/w3/w3types"
+)
+
+type BlockFetcherOpts struct {
+	W3Client *w3.Client
+	Signer   types.Signer
+}
+
+type BlockFetcher struct {
+	opts BlockFetcherOpts
+}
+
+func NewBlockFetcher(o BlockFetcherOpts) *BlockFetcher {
+	return &BlockFetcher{o}
+}
+
+func (bf *BlockFetcher) FetchBlock(ctx context.Context, blockNumber *big.Int) (*FetchResponse, error) {
+	var (
+		block types.Block
+	)
+
+	if err := bf.opts.W3Client.CallCtx(ctx, eth.BlockByNumber(blockNumber).Returns(&block)); err != nil {
+		return &FetchResponse{}, err
+	}
+
+	var (
+		txsCount     = len(block.Transactions())
+		batchedCalls = make([]w3types.Caller, txsCount*2)
+		txs          = make([]types.Transaction, txsCount)
+		receipts     = make([]types.Receipt, txsCount)
+		minimalTxs   = make([]MinimalTransaction, txsCount)
+	)
+
+	for i, block := range block.Transactions() {
+		batchedCalls[i] = eth.Tx(block.Hash()).Returns(&txs[i])
+		batchedCalls[txsCount+i] = eth.TxReceipt(block.Hash()).Returns(&receipts[i])
+	}
+
+	if err := bf.opts.W3Client.CallCtx(ctx, batchedCalls...); err != nil {
+		return &FetchResponse{}, err
+	}
+
+	fetchResponse := &FetchResponse{
+		Block: MinimalBlock{
+			Hash:     block.Hash(),
+			Number:   block.Number(),
+			Bloom:    block.Bloom(),
+			GasLimit: block.GasLimit(),
+			GasUsed:  block.GasUsed(),
+			Time:     block.Time(),
+		},
+		TransactionsCount: txsCount,
+	}
+
+	for i := 0; i < txsCount; i++ {
+		msg, err := txs[i].AsMessage(bf.opts.Signer, nil)
+		if err != nil {
+			return &FetchResponse{}, err
+		}
+
+		minimalTxs[i] = MinimalTransaction{
+			Hash:             txs[i].Hash(),
+			From:             msg.From(),
+			To:               msg.To(),
+			Gas:              msg.Gas(),
+			GasPrice:         msg.GasPrice(),
+			Nonce:            msg.Nonce(),
+			Value:            txs[i].Value(),
+			InputData:        hex.EncodeToString(msg.Data()),
+			TransactionIndex: receipts[i].TransactionIndex,
+			Status:           receipts[i].Status,
+			GasUsed:          receipts[i].GasUsed,
+			Bloom:            receipts[i].Bloom,
+			Logs:             receipts[i].Logs,
+			ContractAddress:  receipts[i].ContractAddress,
+		}
+	}
+
+	fetchResponse.Transactions = minimalTxs
+
+	return fetchResponse, nil
+}