Merge pull request #20 from vulcanize/graphql

Graphql

README.md

@@ -66,15 +66,23 @@ The corresponding CLI flags can be found with the `./ipld-eth-server serve --hel
     ipcPath = "~/.vulcanize/vulcanize.ipc" # $SERVER_IPC_PATH
     wsPath = "127.0.0.1:8081" # $SERVER_WS_PATH
     httpPath = "127.0.0.1:8082" # $SERVER_HTTP_PATH
+    graphql = true # $SERVER_GRAPHQL
+    graphqlEndpoint = "" # $SERVER_GRAPHQL_ENDPOINT
 
 [ethereum]
     chainID = "1" # $ETH_CHAIN_ID
     defaultSender = "" # $ETH_DEFAULT_SENDER_ADDR
+    rpcGasCap = "1000000000000" # $ETH_RPC_GAS_CAP
+    httpPath = "127.0.0.1:8545" # $ETH_HTTP_PATH
+    nodeID = "arch1" # $ETH_NODE_ID
+    clientName = "Geth" # $ETH_CLIENT_NAME
+    genesisBlock = "0xd4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3" # $ETH_GENESIS_BLOCK
+    networkID = "1" # $ETH_NETWORK_ID
 ```
 
-The `database` fields are for connecting to a Postgres database that has been/is being populated by [ipld-eth-indexer](https://github.com/vulcanize/ipld-eth-indexer).
+The `database` fields are for connecting to a Postgres database that has been/is being populated by [ipld-eth-indexer](https://github.com/vulcanize/ipld-eth-indexer)  
 The `server` fields set the paths for exposing the ipld-eth-server endpoints  
-The `ethereum` fields set the chainID and default sender address to use for EVM simulation
+The `ethereum` fields set the chainID and default sender address to use for EVM simulation, and can optionally be used to configure a remote eth node to forward cache misses to  
 
 
 ### Endpoints

cmd/serve.go

@@ -20,6 +20,8 @@ import (
 	"os/signal"
 	"sync"
 
+	"github.com/vulcanize/ipld-eth-server/pkg/graphql"
+
 	"github.com/ethereum/go-ethereum/rpc"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
@@ -28,7 +30,6 @@ import (
 	"github.com/vulcanize/ipld-eth-indexer/pkg/eth"
 
 	srpc "github.com/vulcanize/ipld-eth-server/pkg/rpc"
-
 	s "github.com/vulcanize/ipld-eth-server/pkg/serve"
 	v "github.com/vulcanize/ipld-eth-server/version"
 )
@@ -70,10 +71,17 @@ func serve() {
 	if err := startServers(server, serverConfig); err != nil {
 		logWithCommand.Fatal(err)
 	}
+	graphQL, err := startGraphQL(server)
+	if err != nil {
+		logWithCommand.Fatal(err)
+	}
 
 	shutdown := make(chan os.Signal)
 	signal.Notify(shutdown, os.Interrupt)
 	<-shutdown
+	if graphQL != nil {
+		graphQL.Stop()
+	}
 	server.Stop()
 	wg.Wait()
 }
@@ -91,14 +99,32 @@ func startServers(server s.Server, settings *s.Config) error {
 	}
 	logWithCommand.Info("starting up HTTP server")
 	_, _, err = srpc.StartHTTPEndpoint(settings.HTTPEndpoint, server.APIs(), []string{"eth"}, nil, []string{"*"}, rpc.HTTPTimeouts{})
-
 	return err
 }
 
+func startGraphQL(server s.Server) (graphQLServer *graphql.Service, err error) {
+	viper.BindEnv("server.graphql", "SERVER_GRAPHQL")
+	if viper.GetBool("server.graphql") {
+		logWithCommand.Info("starting up GraphQL server")
+		viper.BindEnv("server.graphqlEndpoint", "SERVER_GRAPHQL_ENDPOINT")
+		endPoint := viper.GetString("server.graphqlEndpoint")
+		if endPoint != "" {
+			graphQLServer, err = graphql.New(server.Backend(), endPoint, nil, []string{"*"}, rpc.HTTPTimeouts{})
+			if err != nil {
+				return
+			}
+			err = graphQLServer.Start(nil)
+		}
+	}
+	return
+}
+
 func init() {
 	rootCmd.AddCommand(serveCmd)
 
 	// flags for all config variables
+	serveCmd.PersistentFlags().Bool("server-graphql", false, "turn on the graphql server")
+	serveCmd.PersistentFlags().String("server-graphql-endpoint", "", "endpoint url for graphql server")
 	serveCmd.PersistentFlags().String("server-ws-path", "", "vdb server ws path")
 	serveCmd.PersistentFlags().String("server-http-path", "", "vdb server http path")
 	serveCmd.PersistentFlags().String("server-ipc-path", "", "vdb server ipc path")
@@ -113,6 +139,8 @@ func init() {
 	serveCmd.PersistentFlags().String("eth-rpc-gas-cap", "", "rpc gas cap (for eth_Call execution)")
 
 	// and their bindings
+	viper.BindPFlag("server.graphql", serveCmd.PersistentFlags().Lookup("server-graphql"))
+	viper.BindPFlag("server.graphqlEndpoint", serveCmd.PersistentFlags().Lookup("server-graphql-endpoint"))
 	viper.BindPFlag("server.wsPath", serveCmd.PersistentFlags().Lookup("server-ws-path"))
 	viper.BindPFlag("server.httpPath", serveCmd.PersistentFlags().Lookup("server-http-path"))
 	viper.BindPFlag("server.ipcPath", serveCmd.PersistentFlags().Lookup("server-ipc-path"))

environments/example.toml

@@ -12,6 +12,8 @@
     ipcPath = "~/.vulcanize/vulcanize.ipc" # $SERVER_IPC_PATH
     wsPath = "127.0.0.1:8081" # $SERVER_WS_PATH
     httpPath = "127.0.0.1:8082" # $SERVER_HTTP_PATH
+    graphql = true # $SERVER_GRAPHQL
+    graphqlEndpoint = "127.0.0.1:8083" # $SERVER_GRAPHQL_ENDPOINT
 
 [ethereum]
     chainID = "1" # $ETH_CHAIN_ID

go.mod

@@ -4,6 +4,7 @@ go 1.13
 
 require (
 	github.com/ethereum/go-ethereum v1.9.11
+	github.com/graph-gophers/graphql-go v0.0.0-20201003130358-c5bdf3b1108e
 	github.com/ipfs/go-block-format v0.0.2
 	github.com/ipfs/go-cid v0.0.5
 	github.com/ipfs/go-ipfs-blockstore v1.0.0

go.sum

@@ -224,6 +224,8 @@ github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/ad
 github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/graph-gophers/graphql-go v0.0.0-20191115155744-f33e81362277/go.mod h1:9CQHMSxwO4MprSdzoIEobiHpoLtHm77vfxsvsIN5Vuc=
+github.com/graph-gophers/graphql-go v0.0.0-20201003130358-c5bdf3b1108e h1:IpssFbpfPSx/3c7x601Npx+UOQ4tqd0Rk4sObCQ+zlQ=
+github.com/graph-gophers/graphql-go v0.0.0-20201003130358-c5bdf3b1108e/go.mod h1:9CQHMSxwO4MprSdzoIEobiHpoLtHm77vfxsvsIN5Vuc=
 github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=
 github.com/grpc-ecosystem/go-grpc-middleware v1.0.0/go.mod h1:FiyG127CGDf3tlThmgyCl78X/SZQqEOJBCDaAfeWzPs=
 github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0/go.mod h1:8NvIoxWQoOIhqOTXgfV/d3M/q6VIi02HzZEHgUlZvzk=

pkg/eth/api.go

@@ -145,11 +145,7 @@ func (pea *PublicEthAPI) getLogs(ctx context.Context, crit ethereum.FilterQuery)
 	startingBlock := crit.FromBlock
 	endingBlock := crit.ToBlock
 	if startingBlock == nil {
-		startingBlockInt, err := pea.B.Retriever.RetrieveFirstBlockNumber()
+		startingBlock = common.Big0
-		if err != nil {
-			return nil, err
-		}
-		startingBlock = big.NewInt(startingBlockInt)
 	}
 	if endingBlock == nil {
 		endingBlockInt, err := pea.B.Retriever.RetrieveLastBlockNumber()

pkg/eth/backend.go

@@ -21,6 +21,9 @@ import (
 	"errors"
 	"math/big"
 
+	"github.com/ethereum/go-ethereum/core/bloombits"
+	"github.com/ethereum/go-ethereum/event"
+
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/common/math"
@@ -36,7 +39,6 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 	ipfsethdb "github.com/vulcanize/pg-ipfs-ethdb"
 
-	"github.com/vulcanize/ipld-eth-indexer/pkg/ipfs"
 	"github.com/vulcanize/ipld-eth-indexer/pkg/postgres"
 	"github.com/vulcanize/ipld-eth-server/pkg/shared"
 )
@@ -53,6 +55,12 @@ const (
 	RetrieveCanonicalHeaderByNumber = `SELECT cid, data FROM eth.header_cids
 									INNER JOIN public.blocks ON (header_cids.mh_key = blocks.key)
 									WHERE id = (SELECT canonical_header($1))`
+	RetrieveTD = `SELECT td FROM eth.header_cids
+			WHERE header_cids.block_hash = $1`
+	RetrieveRPCTransaction = `SELECT blocks.data, block_hash, block_number, index FROM public.blocks, eth.transaction_cids, eth.header_cids
+			WHERE blocks.key = transaction_cids.mh_key
+			AND transaction_cids.header_id = header_cids.id
+			AND transaction_cids.tx_hash = $1`
 )
 
 type Backend struct {
@@ -92,6 +100,11 @@ func NewEthBackend(db *postgres.DB, c *Config) (*Backend, error) {
 	}, nil
 }
 
+// ChainDb returns the backend's underlying chain database
+func (b *Backend) ChainDb() ethdb.Database {
+	return b.EthDB
+}
+
 // HeaderByNumber gets the canonical header for the provided block number
 func (b *Backend) HeaderByNumber(ctx context.Context, blockNumber rpc.BlockNumber) (*types.Header, error) {
 	var err error
@@ -133,12 +146,43 @@ func (b *Backend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.He
 	return header, rlp.DecodeBytes(headerRLP, header)
 }
 
+// HeaderByNumberOrHash gets the header for the provided block hash or number
+func (b *Backend) HeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Header, error) {
+	if blockNr, ok := blockNrOrHash.Number(); ok {
+		return b.HeaderByNumber(ctx, blockNr)
+	}
+	if hash, ok := blockNrOrHash.Hash(); ok {
+		header, err := b.HeaderByHash(ctx, hash)
+		if err != nil {
+			return nil, err
+		}
+		if header == nil {
+			return nil, errors.New("header for hash not found")
+		}
+		if blockNrOrHash.RequireCanonical && b.GetCanonicalHash(header.Number.Uint64()) != hash {
+			return nil, errors.New("hash is not currently canonical")
+		}
+		return header, nil
+	}
+	return nil, errors.New("invalid arguments; neither block nor hash specified")
+}
+
+// rpcMarshalHeader uses the generalized output filler, then adds the total difficulty field, which requires
+// a `PublicEthAPI`.
+func (pea *PublicEthAPI) rpcMarshalHeader(header *types.Header) (map[string]interface{}, error) {
+	fields := RPCMarshalHeader(header)
+	td, err := pea.B.GetTd(header.Hash())
+	if err != nil {
+		return nil, err
+	}
+	fields["totalDifficulty"] = (*hexutil.Big)(td)
+	return fields, nil
+}
+
 // GetTd gets the total difficulty at the given block hash
 func (b *Backend) GetTd(blockHash common.Hash) (*big.Int, error) {
-	pgStr := `SELECT td FROM eth.header_cids
-			WHERE header_cids.block_hash = $1`
 	var tdStr string
-	err := b.DB.Get(&tdStr, pgStr, blockHash.String())
+	err := b.DB.Get(&tdStr, RetrieveTD, blockHash.String())
 	if err != nil {
 		return nil, err
 	}
@@ -149,21 +193,38 @@ func (b *Backend) GetTd(blockHash common.Hash) (*big.Int, error) {
 	return td, nil
 }
 
-// GetLogs returns all the logs for the given block hash
+// CurrentBlock returns the current block
-func (b *Backend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
+func (b *Backend) CurrentBlock() *types.Block {
-	_, receiptBytes, err := b.IPLDRetriever.RetrieveReceiptsByBlockHash(hash)
+	block, _ := b.BlockByNumber(context.Background(), rpc.LatestBlockNumber)
+	return block
+}
+
+// BlockByNumberOrHash returns block by number or hash
+func (b *Backend) BlockByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Block, error) {
+	if blockNr, ok := blockNrOrHash.Number(); ok {
+		return b.BlockByNumber(ctx, blockNr)
+	}
+	if hash, ok := blockNrOrHash.Hash(); ok {
+		header, err := b.HeaderByHash(ctx, hash)
 		if err != nil {
 			return nil, err
 		}
-	logs := make([][]*types.Log, len(receiptBytes))
+		if header == nil {
-	for i, rctBytes := range receiptBytes {
+			return nil, errors.New("header for hash not found")
-		var rct types.Receipt
+		}
-		if err := rlp.DecodeBytes(rctBytes, &rct); err != nil {
+		if blockNrOrHash.RequireCanonical && b.GetCanonicalHash(header.Number.Uint64()) != hash {
+			return nil, errors.New("hash is not currently canonical")
+		}
+		block, err := b.BlockByHash(ctx, hash)
+		if err != nil {
 			return nil, err
 		}
-		logs[i] = rct.Logs
+		if block == nil {
+			return nil, errors.New("header found, but block body is missing")
 		}
-	return logs, nil
+		return block, nil
+	}
+	return nil, errors.New("invalid arguments; neither block nor hash specified")
 }
 
 // BlockByNumber returns the requested canonical block.
@@ -354,11 +415,7 @@ func (b *Backend) GetTransaction(ctx context.Context, txHash common.Hash) (*type
 		BlockNumber uint64 `db:"block_number"`
 		Index       uint64 `db:"index"`
 	}
-	pgStr := `SELECT blocks.data, block_hash, block_number, index FROM public.blocks, eth.transaction_cids, eth.header_cids
+	if err := b.DB.Get(&tempTxStruct, RetrieveRPCTransaction, txHash.String()); err != nil {
-			WHERE blocks.key = transaction_cids.mh_key
-			AND transaction_cids.header_id = header_cids.id
-			AND transaction_cids.tx_hash = $1`
-	if err := b.DB.Get(&tempTxStruct, pgStr, txHash.String()); err != nil {
 		return nil, common.Hash{}, 0, 0, err
 	}
 	var transaction types.Transaction
@@ -368,88 +425,38 @@ func (b *Backend) GetTransaction(ctx context.Context, txHash common.Hash) (*type
 	return &transaction, common.HexToHash(tempTxStruct.BlockHash), tempTxStruct.BlockNumber, tempTxStruct.Index, nil
 }
 
-// extractLogsOfInterest returns logs from the receipt IPLD
+// GetReceipts retrieves receipts for provided block hash
-func extractLogsOfInterest(rctIPLDs []ipfs.BlockModel, wantedTopics [][]string) ([]*types.Log, error) {
+func (b *Backend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
-	var logs []*types.Log
+	_, receiptBytes, err := b.IPLDRetriever.RetrieveReceiptsByBlockHash(hash)
-	for _, rctIPLD := range rctIPLDs {
-		rctRLP := rctIPLD
-		var rct types.Receipt
-		if err := rlp.DecodeBytes(rctRLP.Data, &rct); err != nil {
-			return nil, err
-		}
-		for _, log := range rct.Logs {
-			if wanted := wantedLog(wantedTopics, log.Topics); wanted == true {
-				logs = append(logs, log)
-			}
-		}
-	}
-	return logs, nil
-}
-
-// returns true if the log matches on the filter
-func wantedLog(wantedTopics [][]string, actualTopics []common.Hash) bool {
-	// actualTopics will always have length <= 4
-	// wantedTopics will always have length 4
-	matches := 0
-	for i, actualTopic := range actualTopics {
-		// If we have topics in this filter slot, count as a match if the actualTopic matches one of the ones in this filter slot
-		if len(wantedTopics[i]) > 0 {
-			matches += sliceContainsHash(wantedTopics[i], actualTopic)
-		} else {
-			// Filter slot is empty, not matching any topics at this slot => counts as a match
-			matches++
-		}
-	}
-	if matches == len(actualTopics) {
-		return true
-	}
-	return false
-}
-
-// returns 1 if the slice contains the hash, 0 if it does not
-func sliceContainsHash(slice []string, hash common.Hash) int {
-	for _, str := range slice {
-		if str == hash.String() {
-			return 1
-		}
-	}
-	return 0
-}
-
-// rpcMarshalHeader uses the generalized output filler, then adds the total difficulty field, which requires
-// a `PublicEthAPI`.
-func (pea *PublicEthAPI) rpcMarshalHeader(header *types.Header) (map[string]interface{}, error) {
-	fields := RPCMarshalHeader(header)
-	td, err := pea.B.GetTd(header.Hash())
 	if err != nil {
 		return nil, err
 	}
-	fields["totalDifficulty"] = (*hexutil.Big)(td)
+	rcts := make(types.Receipts, 0, len(receiptBytes))
-	return fields, nil
+	for i, rctBytes := range receiptBytes {
+		rct := new(types.Receipt)
+		if err := rlp.DecodeBytes(rctBytes, rct); err != nil {
+			return nil, err
+		}
+		rcts[i] = rct
+	}
+	return rcts, nil
 }
 
-// RPCMarshalHeader converts the given header to the RPC output.
+// GetLogs returns all the logs for the given block hash
-// This function is eth/internal so we have to make our own version here...
+func (b *Backend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
-func RPCMarshalHeader(head *types.Header) map[string]interface{} {
+	_, receiptBytes, err := b.IPLDRetriever.RetrieveReceiptsByBlockHash(hash)
-	return map[string]interface{}{
+	if err != nil {
-		"number":           (*hexutil.Big)(head.Number),
+		return nil, err
-		"hash":             head.Hash(),
-		"parentHash":       head.ParentHash,
-		"nonce":            head.Nonce,
-		"mixHash":          head.MixDigest,
-		"sha3Uncles":       head.UncleHash,
-		"logsBloom":        head.Bloom,
-		"stateRoot":        head.Root,
-		"miner":            head.Coinbase,
-		"difficulty":       (*hexutil.Big)(head.Difficulty),
-		"extraData":        hexutil.Bytes(head.Extra),
-		"size":             hexutil.Uint64(head.Size()),
-		"gasLimit":         hexutil.Uint64(head.GasLimit),
-		"gasUsed":          hexutil.Uint64(head.GasUsed),
-		"timestamp":        hexutil.Uint64(head.Time),
-		"transactionsRoot": head.TxHash,
-		"receiptsRoot":     head.ReceiptHash,
 	}
+	logs := make([][]*types.Log, len(receiptBytes))
+	for i, rctBytes := range receiptBytes {
+		var rct types.Receipt
+		if err := rlp.DecodeBytes(rctBytes, &rct); err != nil {
+			return nil, err
+		}
+		logs[i] = rct.Logs
+	}
+	return logs, nil
 }
 
 // rpcMarshalBlock uses the generalized output filler, then adds the total difficulty field, which requires
@@ -467,110 +474,6 @@ func (pea *PublicEthAPI) rpcMarshalBlock(b *types.Block, inclTx bool, fullTx boo
 	return fields, err
 }
 
-// RPCMarshalBlock converts the given block to the RPC output which depends on fullTx. If inclTx is true transactions are
-// returned. When fullTx is true the returned block contains full transaction details, otherwise it will only contain
-// transaction hashes.
-func RPCMarshalBlock(block *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
-	fields := RPCMarshalHeader(block.Header())
-	fields["size"] = hexutil.Uint64(block.Size())
-
-	if inclTx {
-		formatTx := func(tx *types.Transaction) (interface{}, error) {
-			return tx.Hash(), nil
-		}
-		if fullTx {
-			formatTx = func(tx *types.Transaction) (interface{}, error) {
-				return NewRPCTransactionFromBlockHash(block, tx.Hash()), nil
-			}
-		}
-		txs := block.Transactions()
-		transactions := make([]interface{}, len(txs))
-		var err error
-		for i, tx := range txs {
-			if transactions[i], err = formatTx(tx); err != nil {
-				return nil, err
-			}
-		}
-		fields["transactions"] = transactions
-	}
-	uncles := block.Uncles()
-	uncleHashes := make([]common.Hash, len(uncles))
-	for i, uncle := range uncles {
-		uncleHashes[i] = uncle.Hash()
-	}
-	fields["uncles"] = uncleHashes
-
-	return fields, nil
-}
-
-// NewRPCTransactionFromBlockHash returns a transaction that will serialize to the RPC representation.
-func NewRPCTransactionFromBlockHash(b *types.Block, hash common.Hash) *RPCTransaction {
-	for idx, tx := range b.Transactions() {
-		if tx.Hash() == hash {
-			return newRPCTransactionFromBlockIndex(b, uint64(idx))
-		}
-	}
-	return nil
-}
-
-// newRPCTransactionFromBlockIndex returns a transaction that will serialize to the RPC representation.
-func newRPCTransactionFromBlockIndex(b *types.Block, index uint64) *RPCTransaction {
-	txs := b.Transactions()
-	if index >= uint64(len(txs)) {
-		return nil
-	}
-	return NewRPCTransaction(txs[index], b.Hash(), b.NumberU64(), index)
-}
-
-// RPCTransaction represents a transaction that will serialize to the RPC representation of a transaction
-type RPCTransaction struct {
-	BlockHash        *common.Hash    `json:"blockHash"`
-	BlockNumber      *hexutil.Big    `json:"blockNumber"`
-	From             common.Address  `json:"from"`
-	Gas              hexutil.Uint64  `json:"gas"`
-	GasPrice         *hexutil.Big    `json:"gasPrice"`
-	Hash             common.Hash     `json:"hash"`
-	Input            hexutil.Bytes   `json:"input"`
-	Nonce            hexutil.Uint64  `json:"nonce"`
-	To               *common.Address `json:"to"`
-	TransactionIndex *hexutil.Uint64 `json:"transactionIndex"`
-	Value            *hexutil.Big    `json:"value"`
-	V                *hexutil.Big    `json:"v"`
-	R                *hexutil.Big    `json:"r"`
-	S                *hexutil.Big    `json:"s"`
-}
-
-// NewRPCTransaction returns a transaction that will serialize to the RPC
-// representation, with the given location metadata set (if available).
-func NewRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber uint64, index uint64) *RPCTransaction {
-	var signer types.Signer = types.FrontierSigner{}
-	if tx.Protected() {
-		signer = types.NewEIP155Signer(tx.ChainId())
-	}
-	from, _ := types.Sender(signer, tx)
-	v, r, s := tx.RawSignatureValues()
-
-	result := &RPCTransaction{
-		From:     from,
-		Gas:      hexutil.Uint64(tx.Gas()),
-		GasPrice: (*hexutil.Big)(tx.GasPrice()),
-		Hash:     tx.Hash(),
-		Input:    hexutil.Bytes(tx.Data()), // somehow this is ending up `nil`
-		Nonce:    hexutil.Uint64(tx.Nonce()),
-		To:       tx.To(),
-		Value:    (*hexutil.Big)(tx.Value()),
-		V:        (*hexutil.Big)(v),
-		R:        (*hexutil.Big)(r),
-		S:        (*hexutil.Big)(s),
-	}
-	if blockHash != (common.Hash{}) {
-		result.BlockHash = &blockHash
-		result.BlockNumber = (*hexutil.Big)(new(big.Int).SetUint64(blockNumber))
-		result.TransactionIndex = (*hexutil.Uint64)(&index)
-	}
-	return result
-}
-
 // StateAndHeaderByNumberOrHash returns the statedb and header for the provided block number or hash
 func (b *Backend) StateAndHeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*state.StateDB, *types.Header, error) {
 	if blockNr, ok := blockNrOrHash.Number(); ok {
@@ -652,3 +555,36 @@ func (b *Backend) GetHeader(hash common.Hash, height uint64) *types.Header {
 	}
 	return header
 }
+
+// RPCGasCap returns the configured gas cap for the rpc server
+func (b *Backend) RPCGasCap() *big.Int {
+	return b.Config.RPCGasCap
+}
+
+func (b *Backend) SubscribeNewTxsEvent(chan<- core.NewTxsEvent) event.Subscription {
+	panic("implement me")
+}
+
+func (b *Backend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
+	panic("implement me")
+}
+
+func (b *Backend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
+	panic("implement me")
+}
+
+func (b *Backend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
+	panic("implement me")
+}
+
+func (b *Backend) SubscribePendingLogsEvent(ch chan<- []*types.Log) event.Subscription {
+	panic("implement me")
+}
+
+func (b *Backend) BloomStatus() (uint64, uint64) {
+	panic("implement me")
+}
+
+func (b *Backend) ServiceFilter(ctx context.Context, session *bloombits.MatcherSession) {
+	panic("implement me")
+}

pkg/eth/backend_utils.go

@@ -0,0 +1,185 @@
+// VulcanizeDB
+// Copyright © 2019 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 eth
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/vulcanize/ipld-eth-indexer/pkg/ipfs"
+)
+
+// RPCMarshalHeader converts the given header to the RPC output.
+// This function is eth/internal so we have to make our own version here...
+func RPCMarshalHeader(head *types.Header) map[string]interface{} {
+	return map[string]interface{}{
+		"number":           (*hexutil.Big)(head.Number),
+		"hash":             head.Hash(),
+		"parentHash":       head.ParentHash,
+		"nonce":            head.Nonce,
+		"mixHash":          head.MixDigest,
+		"sha3Uncles":       head.UncleHash,
+		"logsBloom":        head.Bloom,
+		"stateRoot":        head.Root,
+		"miner":            head.Coinbase,
+		"difficulty":       (*hexutil.Big)(head.Difficulty),
+		"extraData":        hexutil.Bytes(head.Extra),
+		"size":             hexutil.Uint64(head.Size()),
+		"gasLimit":         hexutil.Uint64(head.GasLimit),
+		"gasUsed":          hexutil.Uint64(head.GasUsed),
+		"timestamp":        hexutil.Uint64(head.Time),
+		"transactionsRoot": head.TxHash,
+		"receiptsRoot":     head.ReceiptHash,
+	}
+}
+
+// RPCMarshalBlock converts the given block to the RPC output which depends on fullTx. If inclTx is true transactions are
+// returned. When fullTx is true the returned block contains full transaction details, otherwise it will only contain
+// transaction hashes.
+func RPCMarshalBlock(block *types.Block, inclTx bool, fullTx bool) (map[string]interface{}, error) {
+	fields := RPCMarshalHeader(block.Header())
+	fields["size"] = hexutil.Uint64(block.Size())
+
+	if inclTx {
+		formatTx := func(tx *types.Transaction) (interface{}, error) {
+			return tx.Hash(), nil
+		}
+		if fullTx {
+			formatTx = func(tx *types.Transaction) (interface{}, error) {
+				return NewRPCTransactionFromBlockHash(block, tx.Hash()), nil
+			}
+		}
+		txs := block.Transactions()
+		transactions := make([]interface{}, len(txs))
+		var err error
+		for i, tx := range txs {
+			if transactions[i], err = formatTx(tx); err != nil {
+				return nil, err
+			}
+		}
+		fields["transactions"] = transactions
+	}
+	uncles := block.Uncles()
+	uncleHashes := make([]common.Hash, len(uncles))
+	for i, uncle := range uncles {
+		uncleHashes[i] = uncle.Hash()
+	}
+	fields["uncles"] = uncleHashes
+
+	return fields, nil
+}
+
+// NewRPCTransactionFromBlockHash returns a transaction that will serialize to the RPC representation.
+func NewRPCTransactionFromBlockHash(b *types.Block, hash common.Hash) *RPCTransaction {
+	for idx, tx := range b.Transactions() {
+		if tx.Hash() == hash {
+			return newRPCTransactionFromBlockIndex(b, uint64(idx))
+		}
+	}
+	return nil
+}
+
+// NewRPCTransaction returns a transaction that will serialize to the RPC
+// representation, with the given location metadata set (if available).
+func NewRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber uint64, index uint64) *RPCTransaction {
+	var signer types.Signer = types.FrontierSigner{}
+	if tx.Protected() {
+		signer = types.NewEIP155Signer(tx.ChainId())
+	}
+	from, _ := types.Sender(signer, tx)
+	v, r, s := tx.RawSignatureValues()
+
+	result := &RPCTransaction{
+		From:     from,
+		Gas:      hexutil.Uint64(tx.Gas()),
+		GasPrice: (*hexutil.Big)(tx.GasPrice()),
+		Hash:     tx.Hash(),
+		Input:    hexutil.Bytes(tx.Data()), // somehow this is ending up `nil`
+		Nonce:    hexutil.Uint64(tx.Nonce()),
+		To:       tx.To(),
+		Value:    (*hexutil.Big)(tx.Value()),
+		V:        (*hexutil.Big)(v),
+		R:        (*hexutil.Big)(r),
+		S:        (*hexutil.Big)(s),
+	}
+	if blockHash != (common.Hash{}) {
+		result.BlockHash = &blockHash
+		result.BlockNumber = (*hexutil.Big)(new(big.Int).SetUint64(blockNumber))
+		result.TransactionIndex = (*hexutil.Uint64)(&index)
+	}
+	return result
+}
+
+// newRPCTransactionFromBlockIndex returns a transaction that will serialize to the RPC representation.
+func newRPCTransactionFromBlockIndex(b *types.Block, index uint64) *RPCTransaction {
+	txs := b.Transactions()
+	if index >= uint64(len(txs)) {
+		return nil
+	}
+	return NewRPCTransaction(txs[index], b.Hash(), b.NumberU64(), index)
+}
+
+// extractLogsOfInterest returns logs from the receipt IPLD
+func extractLogsOfInterest(rctIPLDs []ipfs.BlockModel, wantedTopics [][]string) ([]*types.Log, error) {
+	var logs []*types.Log
+	for _, rctIPLD := range rctIPLDs {
+		rctRLP := rctIPLD
+		var rct types.Receipt
+		if err := rlp.DecodeBytes(rctRLP.Data, &rct); err != nil {
+			return nil, err
+		}
+		for _, log := range rct.Logs {
+			if wanted := wantedLog(wantedTopics, log.Topics); wanted == true {
+				logs = append(logs, log)
+			}
+		}
+	}
+	return logs, nil
+}
+
+// returns true if the log matches on the filter
+func wantedLog(wantedTopics [][]string, actualTopics []common.Hash) bool {
+	// actualTopics will always have length <= 4
+	// wantedTopics will always have length 4
+	matches := 0
+	for i, actualTopic := range actualTopics {
+		// If we have topics in this filter slot, count as a match if the actualTopic matches one of the ones in this filter slot
+		if len(wantedTopics[i]) > 0 {
+			matches += sliceContainsHash(wantedTopics[i], actualTopic)
+		} else {
+			// Filter slot is empty, not matching any topics at this slot => counts as a match
+			matches++
+		}
+	}
+	if matches == len(actualTopics) {
+		return true
+	}
+	return false
+}
+
+// returns 1 if the slice contains the hash, 0 if it does not
+func sliceContainsHash(slice []string, hash common.Hash) int {
+	for _, str := range slice {
+		if str == hash.String() {
+			return 1
+		}
+	}
+	return 0
+}

pkg/eth/interfaces.go

@@ -0,0 +1,47 @@
+// VulcanizeDB
+// Copyright © 2019 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 eth
+
+import (
+	"context"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/bloombits"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+// FilterBackend is the geth interface we need to satisfy to use their filters
+type FilterBackend interface {
+	ChainDb() ethdb.Database
+	HeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*types.Header, error)
+	HeaderByHash(ctx context.Context, blockHash common.Hash) (*types.Header, error)
+	GetReceipts(ctx context.Context, blockHash common.Hash) (types.Receipts, error)
+	GetLogs(ctx context.Context, blockHash common.Hash) ([][]*types.Log, error)
+
+	SubscribeNewTxsEvent(chan<- core.NewTxsEvent) event.Subscription
+	SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription
+	SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription
+	SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription
+	SubscribePendingLogsEvent(ch chan<- []*types.Log) event.Subscription
+
+	BloomStatus() (uint64, uint64)
+	ServiceFilter(ctx context.Context, session *bloombits.MatcherSession)
+}

pkg/eth/ipld_retriever.go

@@ -96,8 +96,8 @@ const (
 )
 
 type ipldResult struct {
-	cid  string `db:"cid"`
+	CID  string `db:"cid"`
-	data []byte `db:"data"`
+	Data []byte `db:"data"`
 }
 type IPLDRetriever struct {
 	db *postgres.DB
@@ -122,8 +122,8 @@ func (r *IPLDRetriever) RetrieveHeadersByHashes(hashes []common.Hash) ([]string,
 	cids := make([]string, len(headerResults))
 	headers := make([][]byte, len(headerResults))
 	for i, res := range headerResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		headers[i] = res.data
+		headers[i] = res.Data
 	}
 	return cids, headers, nil
 }
@@ -138,8 +138,8 @@ func (r *IPLDRetriever) RetrieveHeadersByBlockNumber(number uint64) ([]string, [
 	cids := make([]string, len(headerResults))
 	headers := make([][]byte, len(headerResults))
 	for i, res := range headerResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		headers[i] = res.data
+		headers[i] = res.Data
 	}
 	return cids, headers, nil
 }
@@ -147,7 +147,7 @@ func (r *IPLDRetriever) RetrieveHeadersByBlockNumber(number uint64) ([]string, [
 // RetrieveHeaderByHash returns the cid and rlp bytes for the header corresponding to the provided block hash
 func (r *IPLDRetriever) RetrieveHeaderByHash(hash common.Hash) (string, []byte, error) {
 	headerResult := new(ipldResult)
-	return headerResult.cid, headerResult.data, r.db.Get(headerResult, RetrieveHeaderByHashPgStr, hash.Hex())
+	return headerResult.CID, headerResult.Data, r.db.Get(headerResult, RetrieveHeaderByHashPgStr, hash.Hex())
 }
 
 // RetrieveUnclesByHashes returns the cids and rlp bytes for the uncles corresponding to the provided uncle hashes
@@ -163,8 +163,8 @@ func (r *IPLDRetriever) RetrieveUnclesByHashes(hashes []common.Hash) ([]string,
 	cids := make([]string, len(uncleResults))
 	uncles := make([][]byte, len(uncleResults))
 	for i, res := range uncleResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		uncles[i] = res.data
+		uncles[i] = res.Data
 	}
 	return cids, uncles, nil
 }
@@ -178,8 +178,8 @@ func (r *IPLDRetriever) RetrieveUnclesByBlockHash(hash common.Hash) ([]string, [
 	cids := make([]string, len(uncleResults))
 	uncles := make([][]byte, len(uncleResults))
 	for i, res := range uncleResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		uncles[i] = res.data
+		uncles[i] = res.Data
 	}
 	return cids, uncles, nil
 }
@@ -193,8 +193,8 @@ func (r *IPLDRetriever) RetrieveUnclesByBlockNumber(number uint64) ([]string, []
 	cids := make([]string, len(uncleResults))
 	uncles := make([][]byte, len(uncleResults))
 	for i, res := range uncleResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		uncles[i] = res.data
+		uncles[i] = res.Data
 	}
 	return cids, uncles, nil
 }
@@ -202,7 +202,7 @@ func (r *IPLDRetriever) RetrieveUnclesByBlockNumber(number uint64) ([]string, []
 // RetrieveUncleByHash returns the cid and rlp bytes for the uncle corresponding to the provided uncle hash
 func (r *IPLDRetriever) RetrieveUncleByHash(hash common.Hash) (string, []byte, error) {
 	uncleResult := new(ipldResult)
-	return uncleResult.cid, uncleResult.data, r.db.Get(uncleResult, RetrieveUncleByHashPgStr, hash.Hex())
+	return uncleResult.CID, uncleResult.Data, r.db.Get(uncleResult, RetrieveUncleByHashPgStr, hash.Hex())
 }
 
 // RetrieveTransactionsByHashes returns the cids and rlp bytes for the transactions corresponding to the provided tx hashes
@@ -218,8 +218,8 @@ func (r *IPLDRetriever) RetrieveTransactionsByHashes(hashes []common.Hash) ([]st
 	cids := make([]string, len(txResults))
 	txs := make([][]byte, len(txResults))
 	for i, res := range txResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		txs[i] = res.data
+		txs[i] = res.Data
 	}
 	return cids, txs, nil
 }
@@ -233,8 +233,8 @@ func (r *IPLDRetriever) RetrieveTransactionsByBlockHash(hash common.Hash) ([]str
 	cids := make([]string, len(txResults))
 	txs := make([][]byte, len(txResults))
 	for i, res := range txResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		txs[i] = res.data
+		txs[i] = res.Data
 	}
 	return cids, txs, nil
 }
@@ -248,8 +248,8 @@ func (r *IPLDRetriever) RetrieveTransactionsByBlockNumber(number uint64) ([]stri
 	cids := make([]string, len(txResults))
 	txs := make([][]byte, len(txResults))
 	for i, res := range txResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		txs[i] = res.data
+		txs[i] = res.Data
 	}
 	return cids, txs, nil
 }
@@ -257,7 +257,7 @@ func (r *IPLDRetriever) RetrieveTransactionsByBlockNumber(number uint64) ([]stri
 // RetrieveTransactionByTxHash returns the cid and rlp bytes for the transaction corresponding to the provided tx hash
 func (r *IPLDRetriever) RetrieveTransactionByTxHash(hash common.Hash) (string, []byte, error) {
 	txResult := new(ipldResult)
-	return txResult.cid, txResult.data, r.db.Get(txResult, RetrieveTransactionByHashPgStr, hash.Hex())
+	return txResult.CID, txResult.Data, r.db.Get(txResult, RetrieveTransactionByHashPgStr, hash.Hex())
 }
 
 // RetrieveReceiptsByTxHashes returns the cids and rlp bytes for the receipts corresponding to the provided tx hashes
@@ -273,8 +273,8 @@ func (r *IPLDRetriever) RetrieveReceiptsByTxHashes(hashes []common.Hash) ([]stri
 	cids := make([]string, len(rctResults))
 	rcts := make([][]byte, len(rctResults))
 	for i, res := range rctResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		rcts[i] = res.data
+		rcts[i] = res.Data
 	}
 	return cids, rcts, nil
 }
@@ -288,8 +288,8 @@ func (r *IPLDRetriever) RetrieveReceiptsByBlockHash(hash common.Hash) ([]string,
 	cids := make([]string, len(rctResults))
 	rcts := make([][]byte, len(rctResults))
 	for i, res := range rctResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		rcts[i] = res.data
+		rcts[i] = res.Data
 	}
 	return cids, rcts, nil
 }
@@ -303,8 +303,8 @@ func (r *IPLDRetriever) RetrieveReceiptsByBlockNumber(number uint64) ([]string,
 	cids := make([]string, len(rctResults))
 	rcts := make([][]byte, len(rctResults))
 	for i, res := range rctResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
-		rcts[i] = res.data
+		rcts[i] = res.Data
 	}
 	return cids, rcts, nil
 }
@@ -312,7 +312,7 @@ func (r *IPLDRetriever) RetrieveReceiptsByBlockNumber(number uint64) ([]string,
 // RetrieveReceiptByHash returns the cid and rlp bytes for the receipt corresponding to the provided tx hash
 func (r *IPLDRetriever) RetrieveReceiptByHash(hash common.Hash) (string, []byte, error) {
 	rctResult := new(ipldResult)
-	return rctResult.cid, rctResult.data, r.db.Get(rctResult, RetrieveReceiptByTxHashPgStr, hash.Hex())
+	return rctResult.CID, rctResult.Data, r.db.Get(rctResult, RetrieveReceiptByTxHashPgStr, hash.Hex())
 }
 
 // RetrieveAccountByAddressAndBlockHash returns the cid and rlp bytes for the account corresponding to the provided address and block hash
@@ -323,13 +323,13 @@ func (r *IPLDRetriever) RetrieveAccountByAddressAndBlockHash(address common.Addr
 		return "", nil, err
 	}
 	var i []interface{}
-	if err := rlp.DecodeBytes(accountResult.data, &i); err != nil {
+	if err := rlp.DecodeBytes(accountResult.Data, &i); err != nil {
 		return "", nil, fmt.Errorf("error decoding state leaf node rlp: %s", err.Error())
 	}
 	if len(i) != 2 {
 		return "", nil, fmt.Errorf("eth IPLDRetriever expected state leaf node rlp to decode into two elements")
 	}
-	return accountResult.cid, i[1].([]byte), nil
+	return accountResult.CID, i[1].([]byte), nil
 }
 
 // RetrieveAccountByAddressAndBlockNumber returns the cid and rlp bytes for the account corresponding to the provided address and block number
@@ -343,9 +343,9 @@ func (r *IPLDRetriever) RetrieveAccountByAddressAndBlockNumber(address common.Ad
 	cids := make([]string, len(accountResults))
 	accounts := make([][]byte, len(accountResults))
 	for i, res := range accountResults {
-		cids[i] = res.cid
+		cids[i] = res.CID
 		var iface []interface{}
-		if err := rlp.DecodeBytes(res.data, &iface); err != nil {
+		if err := rlp.DecodeBytes(res.Data, &iface); err != nil {
 			return nil, nil, fmt.Errorf("error decoding state leaf node rlp: %s", err.Error())
 		}
 		if len(iface) != 2 {

pkg/eth/types.go

@@ -20,11 +20,30 @@ import (
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/statediff"
 	"github.com/vulcanize/ipld-eth-indexer/pkg/eth"
 	"github.com/vulcanize/ipld-eth-indexer/pkg/ipfs"
 )
 
+// RPCTransaction represents a transaction that will serialize to the RPC representation of a transaction
+type RPCTransaction struct {
+	BlockHash        *common.Hash    `json:"blockHash"`
+	BlockNumber      *hexutil.Big    `json:"blockNumber"`
+	From             common.Address  `json:"from"`
+	Gas              hexutil.Uint64  `json:"gas"`
+	GasPrice         *hexutil.Big    `json:"gasPrice"`
+	Hash             common.Hash     `json:"hash"`
+	Input            hexutil.Bytes   `json:"input"`
+	Nonce            hexutil.Uint64  `json:"nonce"`
+	To               *common.Address `json:"to"`
+	TransactionIndex *hexutil.Uint64 `json:"transactionIndex"`
+	Value            *hexutil.Big    `json:"value"`
+	V                *hexutil.Big    `json:"v"`
+	R                *hexutil.Big    `json:"r"`
+	S                *hexutil.Big    `json:"s"`
+}
+
 // IPLDs is used to package raw IPLD block data fetched from IPFS and returned by the server
 // Returned by IPLDFetcher and ResponseFilterer
 type IPLDs struct {

pkg/graphql/graphiql.go

@@ -0,0 +1,114 @@
+// VulcanizeDB
+// Copyright © 2020 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 graphql
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+)
+
+// GraphiQL is an in-browser IDE for exploring GraphiQL APIs.
+// This handler returns GraphiQL when requested.
+//
+// For more information, see https://github.com/graphql/graphiql.
+type GraphiQL struct{}
+
+func respond(w http.ResponseWriter, body []byte, code int) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("X-Content-Type-Options", "nosniff")
+	w.WriteHeader(code)
+	_, _ = w.Write(body)
+}
+
+func errorJSON(msg string) []byte {
+	buf := bytes.Buffer{}
+	fmt.Fprintf(&buf, `{"error": "%s"}`, msg)
+	return buf.Bytes()
+}
+
+func (h GraphiQL) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "GET" {
+		respond(w, errorJSON("only GET requests are supported"), http.StatusMethodNotAllowed)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html")
+	w.Write(graphiql)
+}
+
+var graphiql = []byte(`
+<!DOCTYPE html>
+<html>
+	<head>
+		<link
+                rel="icon"
+                type="image/png"
+                href="data:image/png;base64,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"
+        />
+        <link
+                rel="stylesheet"
+                href="https://cdnjs.cloudflare.com/ajax/libs/graphiql/0.13.0/graphiql.css"
+                integrity="sha384-Qua2xoKBxcHOg1ivsKWo98zSI5KD/UuBpzMIg8coBd4/jGYoxeozCYFI9fesatT0"
+                crossorigin="anonymous"
+        />
+        <script
+                src="https://cdnjs.cloudflare.com/ajax/libs/fetch/3.0.0/fetch.min.js"
+                integrity="sha384-5B8/4F9AQqp/HCHReGLSOWbyAOwnJsPrvx6C0+VPUr44Olzi99zYT1xbVh+ZanQJ"
+                crossorigin="anonymous"
+        ></script>
+        <script
+                src="https://cdnjs.cloudflare.com/ajax/libs/react/16.8.5/umd/react.production.min.js"
+                integrity="sha384-dOCiLz3nZfHiJj//EWxjwSKSC6Z1IJtyIEK/b/xlHVNdVLXDYSesoxiZb94bbuGE"
+                crossorigin="anonymous"
+        ></script>
+        <script
+                src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.8.5/umd/react-dom.production.min.js"
+                integrity="sha384-QI+ql5f+khgo3mMdCktQ3E7wUKbIpuQo8S5rA/3i1jg2rMsloCNyiZclI7sFQUGN"
+                crossorigin="anonymous"
+        ></script>
+        <script
+                src="https://cdnjs.cloudflare.com/ajax/libs/graphiql/0.13.0/graphiql.min.js"
+                integrity="sha384-roSmzNmO4zJK9X4lwggDi4/oVy+9V4nlS1+MN8Taj7tftJy1GvMWyAhTNXdC/fFR"
+                crossorigin="anonymous"
+        ></script>
+	</head>
+	<body style="width: 100%; height: 100%; margin: 0; overflow: hidden;">
+		<div id="graphiql" style="height: 100vh;">Loading...</div>
+		<script>
+			function fetchGQL(params) {
+				return fetch("/graphql", {
+					method: "post",
+					body: JSON.stringify(params),
+					credentials: "include",
+				}).then(function (resp) {
+					return resp.text();
+				}).then(function (body) {
+					try {
+						return JSON.parse(body);
+					} catch (error) {
+						return body;
+					}
+				});
+			}
+			ReactDOM.render(
+				React.createElement(GraphiQL, {fetcher: fetchGQL}),
+				document.getElementById("graphiql")
+			)
+		</script>
+	</body>
+</html>
+`)

pkg/graphql/graphql.go

@@ -0,0 +1,942 @@
+// VulcanizeDB
+// Copyright © 2020 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 graphql provides a GraphQL interface to Ethereum node data.
+package graphql
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/eth/filters"
+	"github.com/ethereum/go-ethereum/rpc"
+
+	"github.com/vulcanize/ipld-eth-server/pkg/eth"
+)
+
+var (
+	errBlockInvariant = errors.New("block objects must be instantiated with at least one of num or hash")
+)
+
+// Account represents an Ethereum account at a particular block.
+type Account struct {
+	backend       *eth.Backend
+	address       common.Address
+	blockNrOrHash rpc.BlockNumberOrHash
+}
+
+// getState fetches the StateDB object for an account.
+func (a *Account) getState(ctx context.Context) (*state.StateDB, error) {
+	state, _, err := a.backend.StateAndHeaderByNumberOrHash(ctx, a.blockNrOrHash)
+	return state, err
+}
+
+func (a *Account) Address(ctx context.Context) (common.Address, error) {
+	return a.address, nil
+}
+
+func (a *Account) Balance(ctx context.Context) (hexutil.Big, error) {
+	state, err := a.getState(ctx)
+	if err != nil {
+		return hexutil.Big{}, err
+	}
+	return hexutil.Big(*state.GetBalance(a.address)), nil
+}
+
+func (a *Account) TransactionCount(ctx context.Context) (hexutil.Uint64, error) {
+	state, err := a.getState(ctx)
+	if err != nil {
+		return 0, err
+	}
+	return hexutil.Uint64(state.GetNonce(a.address)), nil
+}
+
+func (a *Account) Code(ctx context.Context) (hexutil.Bytes, error) {
+	state, err := a.getState(ctx)
+	if err != nil {
+		return hexutil.Bytes{}, err
+	}
+	return hexutil.Bytes(state.GetCode(a.address)), nil
+}
+
+func (a *Account) Storage(ctx context.Context, args struct{ Slot common.Hash }) (common.Hash, error) {
+	state, err := a.getState(ctx)
+	if err != nil {
+		return common.Hash{}, err
+	}
+	return state.GetState(a.address, args.Slot), nil
+}
+
+// Log represents an individual log message. All arguments are mandatory.
+type Log struct {
+	backend     *eth.Backend
+	transaction *Transaction
+	log         *types.Log
+}
+
+func (l *Log) Transaction(ctx context.Context) *Transaction {
+	return l.transaction
+}
+
+func (l *Log) Account(ctx context.Context, args BlockNumberArgs) *Account {
+	return &Account{
+		backend:       l.backend,
+		address:       l.log.Address,
+		blockNrOrHash: args.NumberOrLatest(),
+	}
+}
+
+func (l *Log) Index(ctx context.Context) int32 {
+	return int32(l.log.Index)
+}
+
+func (l *Log) Topics(ctx context.Context) []common.Hash {
+	return l.log.Topics
+}
+
+func (l *Log) Data(ctx context.Context) hexutil.Bytes {
+	return hexutil.Bytes(l.log.Data)
+}
+
+// Transaction represents an Ethereum transaction.
+// backend and hash are mandatory; all others will be fetched when required.
+type Transaction struct {
+	backend *eth.Backend
+	hash    common.Hash
+	tx      *types.Transaction
+	block   *Block
+	index   uint64
+}
+
+// resolve returns the internal transaction object, fetching it if needed.
+func (t *Transaction) resolve(ctx context.Context) (*types.Transaction, error) {
+	if t.tx == nil {
+		tx, blockHash, _, index := rawdb.ReadTransaction(t.backend.ChainDb(), t.hash)
+		if tx != nil {
+			t.tx = tx
+			blockNrOrHash := rpc.BlockNumberOrHashWithHash(blockHash, false)
+			t.block = &Block{
+				backend:      t.backend,
+				numberOrHash: &blockNrOrHash,
+			}
+			t.index = index
+		}
+	}
+	return t.tx, nil
+}
+
+func (t *Transaction) Hash(ctx context.Context) common.Hash {
+	return t.hash
+}
+
+func (t *Transaction) InputData(ctx context.Context) (hexutil.Bytes, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return hexutil.Bytes{}, err
+	}
+	return hexutil.Bytes(tx.Data()), nil
+}
+
+func (t *Transaction) Gas(ctx context.Context) (hexutil.Uint64, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return 0, err
+	}
+	return hexutil.Uint64(tx.Gas()), nil
+}
+
+func (t *Transaction) GasPrice(ctx context.Context) (hexutil.Big, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return hexutil.Big{}, err
+	}
+	return hexutil.Big(*tx.GasPrice()), nil
+}
+
+func (t *Transaction) Value(ctx context.Context) (hexutil.Big, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return hexutil.Big{}, err
+	}
+	return hexutil.Big(*tx.Value()), nil
+}
+
+func (t *Transaction) Nonce(ctx context.Context) (hexutil.Uint64, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return 0, err
+	}
+	return hexutil.Uint64(tx.Nonce()), nil
+}
+
+func (t *Transaction) To(ctx context.Context, args BlockNumberArgs) (*Account, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return nil, err
+	}
+	to := tx.To()
+	if to == nil {
+		return nil, nil
+	}
+	return &Account{
+		backend:       t.backend,
+		address:       *to,
+		blockNrOrHash: args.NumberOrLatest(),
+	}, nil
+}
+
+func (t *Transaction) From(ctx context.Context, args BlockNumberArgs) (*Account, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return nil, err
+	}
+	var signer types.Signer = types.HomesteadSigner{}
+	if tx.Protected() {
+		signer = types.NewEIP155Signer(tx.ChainId())
+	}
+	from, _ := types.Sender(signer, tx)
+
+	return &Account{
+		backend:       t.backend,
+		address:       from,
+		blockNrOrHash: args.NumberOrLatest(),
+	}, nil
+}
+
+func (t *Transaction) Block(ctx context.Context) (*Block, error) {
+	if _, err := t.resolve(ctx); err != nil {
+		return nil, err
+	}
+	return t.block, nil
+}
+
+func (t *Transaction) Index(ctx context.Context) (*int32, error) {
+	if _, err := t.resolve(ctx); err != nil {
+		return nil, err
+	}
+	if t.block == nil {
+		return nil, nil
+	}
+	index := int32(t.index)
+	return &index, nil
+}
+
+// getReceipt returns the receipt associated with this transaction, if any.
+func (t *Transaction) getReceipt(ctx context.Context) (*types.Receipt, error) {
+	if _, err := t.resolve(ctx); err != nil {
+		return nil, err
+	}
+	if t.block == nil {
+		return nil, nil
+	}
+	receipts, err := t.block.resolveReceipts(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return receipts[t.index], nil
+}
+
+func (t *Transaction) Status(ctx context.Context) (*hexutil.Uint64, error) {
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil {
+		return nil, err
+	}
+	ret := hexutil.Uint64(receipt.Status)
+	return &ret, nil
+}
+
+func (t *Transaction) GasUsed(ctx context.Context) (*hexutil.Uint64, error) {
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil {
+		return nil, err
+	}
+	ret := hexutil.Uint64(receipt.GasUsed)
+	return &ret, nil
+}
+
+func (t *Transaction) CumulativeGasUsed(ctx context.Context) (*hexutil.Uint64, error) {
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil {
+		return nil, err
+	}
+	ret := hexutil.Uint64(receipt.CumulativeGasUsed)
+	return &ret, nil
+}
+
+func (t *Transaction) CreatedContract(ctx context.Context, args BlockNumberArgs) (*Account, error) {
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil || receipt.ContractAddress == (common.Address{}) {
+		return nil, err
+	}
+	return &Account{
+		backend:       t.backend,
+		address:       receipt.ContractAddress,
+		blockNrOrHash: args.NumberOrLatest(),
+	}, nil
+}
+
+func (t *Transaction) Logs(ctx context.Context) (*[]*Log, error) {
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil {
+		return nil, err
+	}
+	ret := make([]*Log, 0, len(receipt.Logs))
+	for _, log := range receipt.Logs {
+		ret = append(ret, &Log{
+			backend:     t.backend,
+			transaction: t,
+			log:         log,
+		})
+	}
+	return &ret, nil
+}
+
+func (t *Transaction) R(ctx context.Context) (hexutil.Big, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return hexutil.Big{}, err
+	}
+	_, r, _ := tx.RawSignatureValues()
+	return hexutil.Big(*r), nil
+}
+
+func (t *Transaction) S(ctx context.Context) (hexutil.Big, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return hexutil.Big{}, err
+	}
+	_, _, s := tx.RawSignatureValues()
+	return hexutil.Big(*s), nil
+}
+
+func (t *Transaction) V(ctx context.Context) (hexutil.Big, error) {
+	tx, err := t.resolve(ctx)
+	if err != nil || tx == nil {
+		return hexutil.Big{}, err
+	}
+	v, _, _ := tx.RawSignatureValues()
+	return hexutil.Big(*v), nil
+}
+
+type BlockType int
+
+// Block represents an Ethereum block.
+// backend, and numberOrHash are mandatory. All other fields are lazily fetched
+// when required.
+type Block struct {
+	backend      *eth.Backend
+	numberOrHash *rpc.BlockNumberOrHash
+	hash         common.Hash
+	header       *types.Header
+	block        *types.Block
+	receipts     []*types.Receipt
+}
+
+// resolve returns the internal Block object representing this block, fetching
+// it if necessary.
+func (b *Block) resolve(ctx context.Context) (*types.Block, error) {
+	if b.block != nil {
+		return b.block, nil
+	}
+	if b.numberOrHash == nil {
+		latest := rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber)
+		b.numberOrHash = &latest
+	}
+	var err error
+	b.block, err = b.backend.BlockByNumberOrHash(ctx, *b.numberOrHash)
+	if b.block != nil && b.header == nil {
+		b.header = b.block.Header()
+		if hash, ok := b.numberOrHash.Hash(); ok {
+			b.hash = hash
+		}
+	}
+	return b.block, err
+}
+
+// resolveHeader returns the internal Header object for this block, fetching it
+// if necessary. Call this function instead of `resolve` unless you need the
+// additional data (transactions and uncles).
+func (b *Block) resolveHeader(ctx context.Context) (*types.Header, error) {
+	if b.numberOrHash == nil && b.hash == (common.Hash{}) {
+		return nil, errBlockInvariant
+	}
+	var err error
+	if b.header == nil {
+		if b.hash != (common.Hash{}) {
+			b.header, err = b.backend.HeaderByHash(ctx, b.hash)
+		} else {
+			b.header, err = b.backend.HeaderByNumberOrHash(ctx, *b.numberOrHash)
+		}
+	}
+	return b.header, err
+}
+
+// resolveReceipts returns the list of receipts for this block, fetching them
+// if necessary.
+func (b *Block) resolveReceipts(ctx context.Context) ([]*types.Receipt, error) {
+	if b.receipts == nil {
+		hash := b.hash
+		if hash == (common.Hash{}) {
+			header, err := b.resolveHeader(ctx)
+			if err != nil {
+				return nil, err
+			}
+			hash = header.Hash()
+		}
+		receipts, err := b.backend.GetReceipts(ctx, hash)
+		if err != nil {
+			return nil, err
+		}
+		b.receipts = []*types.Receipt(receipts)
+	}
+	return b.receipts, nil
+}
+
+func (b *Block) Number(ctx context.Context) (hexutil.Uint64, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return 0, err
+	}
+
+	return hexutil.Uint64(header.Number.Uint64()), nil
+}
+
+func (b *Block) Hash(ctx context.Context) (common.Hash, error) {
+	if b.hash == (common.Hash{}) {
+		header, err := b.resolveHeader(ctx)
+		if err != nil {
+			return common.Hash{}, err
+		}
+		b.hash = header.Hash()
+	}
+	return b.hash, nil
+}
+
+func (b *Block) GasLimit(ctx context.Context) (hexutil.Uint64, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return 0, err
+	}
+	return hexutil.Uint64(header.GasLimit), nil
+}
+
+func (b *Block) GasUsed(ctx context.Context) (hexutil.Uint64, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return 0, err
+	}
+	return hexutil.Uint64(header.GasUsed), nil
+}
+
+func (b *Block) Parent(ctx context.Context) (*Block, error) {
+	// If the block header hasn't been fetched, and we'll need it, fetch it.
+	if b.numberOrHash == nil && b.header == nil {
+		if _, err := b.resolveHeader(ctx); err != nil {
+			return nil, err
+		}
+	}
+	if b.header != nil && b.header.Number.Uint64() > 0 {
+		num := rpc.BlockNumberOrHashWithNumber(rpc.BlockNumber(b.header.Number.Uint64() - 1))
+		return &Block{
+			backend:      b.backend,
+			numberOrHash: &num,
+			hash:         b.header.ParentHash,
+		}, nil
+	}
+	return nil, nil
+}
+
+func (b *Block) Difficulty(ctx context.Context) (hexutil.Big, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return hexutil.Big{}, err
+	}
+	return hexutil.Big(*header.Difficulty), nil
+}
+
+func (b *Block) Timestamp(ctx context.Context) (hexutil.Uint64, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return 0, err
+	}
+	return hexutil.Uint64(header.Time), nil
+}
+
+func (b *Block) Nonce(ctx context.Context) (hexutil.Bytes, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return hexutil.Bytes{}, err
+	}
+	return hexutil.Bytes(header.Nonce[:]), nil
+}
+
+func (b *Block) MixHash(ctx context.Context) (common.Hash, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return common.Hash{}, err
+	}
+	return header.MixDigest, nil
+}
+
+func (b *Block) TransactionsRoot(ctx context.Context) (common.Hash, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return common.Hash{}, err
+	}
+	return header.TxHash, nil
+}
+
+func (b *Block) StateRoot(ctx context.Context) (common.Hash, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return common.Hash{}, err
+	}
+	return header.Root, nil
+}
+
+func (b *Block) ReceiptsRoot(ctx context.Context) (common.Hash, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return common.Hash{}, err
+	}
+	return header.ReceiptHash, nil
+}
+
+func (b *Block) OmmerHash(ctx context.Context) (common.Hash, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return common.Hash{}, err
+	}
+	return header.UncleHash, nil
+}
+
+func (b *Block) OmmerCount(ctx context.Context) (*int32, error) {
+	block, err := b.resolve(ctx)
+	if err != nil || block == nil {
+		return nil, err
+	}
+	count := int32(len(block.Uncles()))
+	return &count, err
+}
+
+func (b *Block) Ommers(ctx context.Context) (*[]*Block, error) {
+	block, err := b.resolve(ctx)
+	if err != nil || block == nil {
+		return nil, err
+	}
+	ret := make([]*Block, 0, len(block.Uncles()))
+	for _, uncle := range block.Uncles() {
+		blockNumberOrHash := rpc.BlockNumberOrHashWithHash(uncle.Hash(), false)
+		ret = append(ret, &Block{
+			backend:      b.backend,
+			numberOrHash: &blockNumberOrHash,
+			header:       uncle,
+		})
+	}
+	return &ret, nil
+}
+
+func (b *Block) ExtraData(ctx context.Context) (hexutil.Bytes, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return hexutil.Bytes{}, err
+	}
+	return hexutil.Bytes(header.Extra), nil
+}
+
+func (b *Block) LogsBloom(ctx context.Context) (hexutil.Bytes, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return hexutil.Bytes{}, err
+	}
+	return hexutil.Bytes(header.Bloom.Bytes()), nil
+}
+
+func (b *Block) TotalDifficulty(ctx context.Context) (hexutil.Big, error) {
+	h := b.hash
+	if h == (common.Hash{}) {
+		header, err := b.resolveHeader(ctx)
+		if err != nil {
+			return hexutil.Big{}, err
+		}
+		h = header.Hash()
+	}
+	td, err := b.backend.GetTd(h)
+	if err != nil {
+		return hexutil.Big{}, err
+	}
+	return hexutil.Big(*td), nil
+}
+
+// BlockNumberArgs encapsulates arguments to accessors that specify a block number.
+type BlockNumberArgs struct {
+	// TODO: Ideally we could use input unions to allow the query to specify the
+	// block parameter by hash, block number, or tag but input unions aren't part of the
+	// standard GraphQL schema SDL yet, see: https://github.com/graphql/graphql-spec/issues/488
+	Block *hexutil.Uint64
+}
+
+// NumberOr returns the provided block number argument, or the "current" block number or hash if none
+// was provided.
+func (a BlockNumberArgs) NumberOr(current rpc.BlockNumberOrHash) rpc.BlockNumberOrHash {
+	if a.Block != nil {
+		blockNr := rpc.BlockNumber(*a.Block)
+		return rpc.BlockNumberOrHashWithNumber(blockNr)
+	}
+	return current
+}
+
+// NumberOrLatest returns the provided block number argument, or the "latest" block number if none
+// was provided.
+func (a BlockNumberArgs) NumberOrLatest() rpc.BlockNumberOrHash {
+	return a.NumberOr(rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber))
+}
+
+func (b *Block) Miner(ctx context.Context, args BlockNumberArgs) (*Account, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return &Account{
+		backend:       b.backend,
+		address:       header.Coinbase,
+		blockNrOrHash: args.NumberOrLatest(),
+	}, nil
+}
+
+func (b *Block) TransactionCount(ctx context.Context) (*int32, error) {
+	block, err := b.resolve(ctx)
+	if err != nil || block == nil {
+		return nil, err
+	}
+	count := int32(len(block.Transactions()))
+	return &count, err
+}
+
+func (b *Block) Transactions(ctx context.Context) (*[]*Transaction, error) {
+	block, err := b.resolve(ctx)
+	if err != nil || block == nil {
+		return nil, err
+	}
+	ret := make([]*Transaction, 0, len(block.Transactions()))
+	for i, tx := range block.Transactions() {
+		ret = append(ret, &Transaction{
+			backend: b.backend,
+			hash:    tx.Hash(),
+			tx:      tx,
+			block:   b,
+			index:   uint64(i),
+		})
+	}
+	return &ret, nil
+}
+
+func (b *Block) TransactionAt(ctx context.Context, args struct{ Index int32 }) (*Transaction, error) {
+	block, err := b.resolve(ctx)
+	if err != nil || block == nil {
+		return nil, err
+	}
+	txs := block.Transactions()
+	if args.Index < 0 || int(args.Index) >= len(txs) {
+		return nil, nil
+	}
+	tx := txs[args.Index]
+	return &Transaction{
+		backend: b.backend,
+		hash:    tx.Hash(),
+		tx:      tx,
+		block:   b,
+		index:   uint64(args.Index),
+	}, nil
+}
+
+func (b *Block) OmmerAt(ctx context.Context, args struct{ Index int32 }) (*Block, error) {
+	block, err := b.resolve(ctx)
+	if err != nil || block == nil {
+		return nil, err
+	}
+	uncles := block.Uncles()
+	if args.Index < 0 || int(args.Index) >= len(uncles) {
+		return nil, nil
+	}
+	uncle := uncles[args.Index]
+	blockNumberOrHash := rpc.BlockNumberOrHashWithHash(uncle.Hash(), false)
+	return &Block{
+		backend:      b.backend,
+		numberOrHash: &blockNumberOrHash,
+		header:       uncle,
+	}, nil
+}
+
+// BlockFilterCriteria encapsulates criteria passed to a `logs` accessor inside
+// a block.
+type BlockFilterCriteria struct {
+	Addresses *[]common.Address // restricts matches to events created by specific contracts
+
+	// The Topic list restricts matches to particular event topics. Each event has a list
+	// of topics. Topics matches a prefix of that list. An empty element slice matches any
+	// topic. Non-empty elements represent an alternative that matches any of the
+	// contained topics.
+	//
+	// Examples:
+	// {} or nil          matches any topic list
+	// {{A}}              matches topic A in first position
+	// {{}, {B}}          matches any topic in first position, B in second position
+	// {{A}, {B}}         matches topic A in first position, B in second position
+	// {{A, B}}, {C, D}}  matches topic (A OR B) in first position, (C OR D) in second position
+	Topics *[][]common.Hash
+}
+
+// runFilter accepts a filter and executes it, returning all its results as
+// `Log` objects.
+func runFilter(ctx context.Context, be *eth.Backend, filter *filters.Filter) ([]*Log, error) {
+	logs, err := filter.Logs(ctx)
+	if err != nil || logs == nil {
+		return nil, err
+	}
+	ret := make([]*Log, 0, len(logs))
+	for _, log := range logs {
+		ret = append(ret, &Log{
+			backend:     be,
+			transaction: &Transaction{backend: be, hash: log.TxHash},
+			log:         log,
+		})
+	}
+	return ret, nil
+}
+
+func (b *Block) Logs(ctx context.Context, args struct{ Filter BlockFilterCriteria }) ([]*Log, error) {
+	var addresses []common.Address
+	if args.Filter.Addresses != nil {
+		addresses = *args.Filter.Addresses
+	}
+	var topics [][]common.Hash
+	if args.Filter.Topics != nil {
+		topics = *args.Filter.Topics
+	}
+	hash := b.hash
+	if hash == (common.Hash{}) {
+		header, err := b.resolveHeader(ctx)
+		if err != nil {
+			return nil, err
+		}
+		hash = header.Hash()
+	}
+	// Construct the range filter
+	filter := filters.NewBlockFilter(b.backend, hash, addresses, topics)
+
+	// Run the filter and return all the logs
+	return runFilter(ctx, b.backend, filter)
+}
+
+func (b *Block) Account(ctx context.Context, args struct {
+	Address common.Address
+}) (*Account, error) {
+	if b.numberOrHash == nil {
+		_, err := b.resolveHeader(ctx)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return &Account{
+		backend:       b.backend,
+		address:       args.Address,
+		blockNrOrHash: *b.numberOrHash,
+	}, nil
+}
+
+// CallData encapsulates arguments to `call` or `estimateGas`.
+// All arguments are optional.
+type CallData struct {
+	From     *common.Address // The Ethereum address the call is from.
+	To       *common.Address // The Ethereum address the call is to.
+	Gas      *hexutil.Uint64 // The amount of gas provided for the call.
+	GasPrice *hexutil.Big    // The price of each unit of gas, in wei.
+	Value    *hexutil.Big    // The value sent along with the call.
+	Data     *hexutil.Bytes  // Any data sent with the call.
+}
+
+// CallResult encapsulates the result of an invocation of the `call` accessor.
+type CallResult struct {
+	data    hexutil.Bytes  // The return data from the call
+	gasUsed hexutil.Uint64 // The amount of gas used
+	status  hexutil.Uint64 // The return status of the call - 0 for failure or 1 for success.
+}
+
+func (c *CallResult) Data() hexutil.Bytes {
+	return c.data
+}
+
+func (c *CallResult) GasUsed() hexutil.Uint64 {
+	return c.gasUsed
+}
+
+func (c *CallResult) Status() hexutil.Uint64 {
+	return c.status
+}
+
+func (b *Block) Call(ctx context.Context, args struct {
+	Data eth.CallArgs
+}) (*CallResult, error) {
+	if b.numberOrHash == nil {
+		_, err := b.resolve(ctx)
+		if err != nil {
+			return nil, err
+		}
+	}
+	result, gas, failed, err := eth.DoCall(ctx, b.backend, args.Data, *b.numberOrHash, nil, 5*time.Second, b.backend.RPCGasCap())
+	status := hexutil.Uint64(1)
+	if failed {
+		status = 0
+	}
+	return &CallResult{
+		data:    hexutil.Bytes(result),
+		gasUsed: hexutil.Uint64(gas),
+		status:  status,
+	}, err
+}
+
+// Resolver is the top-level object in the GraphQL hierarchy.
+type Resolver struct {
+	backend *eth.Backend
+}
+
+func (r *Resolver) Block(ctx context.Context, args struct {
+	Number *hexutil.Uint64
+	Hash   *common.Hash
+}) (*Block, error) {
+	var block *Block
+	if args.Number != nil {
+		number := rpc.BlockNumber(uint64(*args.Number))
+		numberOrHash := rpc.BlockNumberOrHashWithNumber(number)
+		block = &Block{
+			backend:      r.backend,
+			numberOrHash: &numberOrHash,
+		}
+	} else if args.Hash != nil {
+		numberOrHash := rpc.BlockNumberOrHashWithHash(*args.Hash, false)
+		block = &Block{
+			backend:      r.backend,
+			numberOrHash: &numberOrHash,
+		}
+	} else {
+		numberOrHash := rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber)
+		block = &Block{
+			backend:      r.backend,
+			numberOrHash: &numberOrHash,
+		}
+	}
+	// Resolve the header, return nil if it doesn't exist.
+	// Note we don't resolve block directly here since it will require an
+	// additional network request for light client.
+	h, err := block.resolveHeader(ctx)
+	if err != nil {
+		return nil, err
+	} else if h == nil {
+		return nil, nil
+	}
+	return block, nil
+}
+
+func (r *Resolver) Blocks(ctx context.Context, args struct {
+	From hexutil.Uint64
+	To   *hexutil.Uint64
+}) ([]*Block, error) {
+	from := rpc.BlockNumber(args.From)
+
+	var to rpc.BlockNumber
+	if args.To != nil {
+		to = rpc.BlockNumber(*args.To)
+	} else {
+		to = rpc.BlockNumber(r.backend.CurrentBlock().Number().Int64())
+	}
+	if to < from {
+		return []*Block{}, nil
+	}
+	ret := make([]*Block, 0, to-from+1)
+	for i := from; i <= to; i++ {
+		numberOrHash := rpc.BlockNumberOrHashWithNumber(i)
+		ret = append(ret, &Block{
+			backend:      r.backend,
+			numberOrHash: &numberOrHash,
+		})
+	}
+	return ret, nil
+}
+
+func (r *Resolver) Transaction(ctx context.Context, args struct{ Hash common.Hash }) (*Transaction, error) {
+	tx := &Transaction{
+		backend: r.backend,
+		hash:    args.Hash,
+	}
+	// Resolve the transaction; if it doesn't exist, return nil.
+	t, err := tx.resolve(ctx)
+	if err != nil {
+		return nil, err
+	} else if t == nil {
+		return nil, nil
+	}
+	return tx, nil
+}
+
+// FilterCriteria encapsulates the arguments to `logs` on the root resolver object.
+type FilterCriteria struct {
+	FromBlock *hexutil.Uint64   // beginning of the queried range, nil means genesis block
+	ToBlock   *hexutil.Uint64   // end of the range, nil means latest block
+	Addresses *[]common.Address // restricts matches to events created by specific contracts
+
+	// The Topic list restricts matches to particular event topics. Each event has a list
+	// of topics. Topics matches a prefix of that list. An empty element slice matches any
+	// topic. Non-empty elements represent an alternative that matches any of the
+	// contained topics.
+	//
+	// Examples:
+	// {} or nil          matches any topic list
+	// {{A}}              matches topic A in first position
+	// {{}, {B}}          matches any topic in first position, B in second position
+	// {{A}, {B}}         matches topic A in first position, B in second position
+	// {{A, B}}, {C, D}}  matches topic (A OR B) in first position, (C OR D) in second position
+	Topics *[][]common.Hash
+}
+
+func (r *Resolver) Logs(ctx context.Context, args struct{ Filter FilterCriteria }) ([]*Log, error) {
+	// Convert the RPC block numbers into internal representations
+	begin := rpc.LatestBlockNumber.Int64()
+	if args.Filter.FromBlock != nil {
+		begin = int64(*args.Filter.FromBlock)
+	}
+	end := rpc.LatestBlockNumber.Int64()
+	if args.Filter.ToBlock != nil {
+		end = int64(*args.Filter.ToBlock)
+	}
+	var addresses []common.Address
+	if args.Filter.Addresses != nil {
+		addresses = *args.Filter.Addresses
+	}
+	var topics [][]common.Hash
+	if args.Filter.Topics != nil {
+		topics = *args.Filter.Topics
+	}
+	// Construct the range filter
+	filter := filters.NewRangeFilter(filters.Backend(r.backend), begin, end, addresses, topics)
+	return runFilter(ctx, r.backend, filter)
+}

pkg/graphql/graphql_suite_test.go

@@ -0,0 +1,35 @@
+// VulcanizeDB
+// Copyright © 2020 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 graphql_test
+
+import (
+	"io/ioutil"
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"github.com/sirupsen/logrus"
+)
+
+func TestGraphQL(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "graphql test suite")
+}
+
+var _ = BeforeSuite(func() {
+	logrus.SetOutput(ioutil.Discard)
+})

pkg/graphql/graphql_test.go

@@ -0,0 +1,31 @@
+// VulcanizeDB
+// Copyright © 2020 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 graphql_test
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"github.com/vulcanize/ipld-eth-server/pkg/graphql"
+)
+
+var _ = Describe("GraphQL", func() {
+	It("Builds the schema and creates a new handler", func() {
+		_, err := graphql.NewHandler(nil)
+		Expect(err).ToNot(HaveOccurred())
+	})
+})

pkg/graphql/schema.go

@@ -0,0 +1,274 @@
+// VulcanizeDB
+// Copyright © 2020 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 graphql
+
+const schema string = `
+    # Bytes32 is a 32 byte binary string, represented as 0x-prefixed hexadecimal.
+    scalar Bytes32
+    # Address is a 20 byte Ethereum address, represented as 0x-prefixed hexadecimal.
+    scalar Address
+    # Bytes is an arbitrary length binary string, represented as 0x-prefixed hexadecimal.
+    # An empty byte string is represented as '0x'. Byte strings must have an even number of hexadecimal nybbles.
+    scalar Bytes
+    # BigInt is a large integer. Input is accepted as either a JSON number or as a string.
+    # Strings may be either decimal or 0x-prefixed hexadecimal. Output values are all
+    # 0x-prefixed hexadecimal.
+    scalar BigInt
+    # Long is a 64 bit unsigned integer.
+    scalar Long
+
+    schema {
+        query: Query
+    }
+
+    # Account is an Ethereum account at a particular block.
+    type Account {
+        # Address is the address owning the account.
+        address: Address!
+        # Balance is the balance of the account, in wei.
+        balance: BigInt!
+        # TransactionCount is the number of transactions sent from this account,
+        # or in the case of a contract, the number of contracts created. Otherwise
+        # known as the nonce.
+        transactionCount: Long!
+        # Code contains the smart contract code for this account, if the account
+        # is a (non-self-destructed) contract.
+        code: Bytes!
+        # Storage provides access to the storage of a contract account, indexed
+        # by its 32 byte slot identifier.
+        storage(slot: Bytes32!): Bytes32!
+    }
+
+    # Log is an Ethereum event log.
+    type Log {
+        # Index is the index of this log in the block.
+        index: Int!
+        # Account is the account which generated this log - this will always
+        # be a contract account.
+        account(block: Long): Account!
+        # Topics is a list of 0-4 indexed topics for the log.
+        topics: [Bytes32!]!
+        # Data is unindexed data for this log.
+        data: Bytes!
+        # Transaction is the transaction that generated this log entry.
+        transaction: Transaction!
+    }
+
+    # Transaction is an Ethereum transaction.
+    type Transaction {
+        # Hash is the hash of this transaction.
+        hash: Bytes32!
+        # Nonce is the nonce of the account this transaction was generated with.
+        nonce: Long!
+        # Index is the index of this transaction in the parent block. This will
+        # be null if the transaction has not yet been mined.
+        index: Int
+        # From is the account that sent this transaction - this will always be
+        # an externally owned account.
+        from(block: Long): Account!
+        # To is the account the transaction was sent to. This is null for
+        # contract-creating transactions.
+        to(block: Long): Account
+        # Value is the value, in wei, sent along with this transaction.
+        value: BigInt!
+        # GasPrice is the price offered to miners for gas, in wei per unit.
+        gasPrice: BigInt!
+        # Gas is the maximum amount of gas this transaction can consume.
+        gas: Long!
+        # InputData is the data supplied to the target of the transaction.
+        inputData: Bytes!
+        # Block is the block this transaction was mined in. This will be null if
+        # the transaction has not yet been mined.
+        block: Block
+
+        # Status is the return status of the transaction. This will be 1 if the
+        # transaction succeeded, or 0 if it failed (due to a revert, or due to
+        # running out of gas). If the transaction has not yet been mined, this
+        # field will be null.
+        status: Long
+        # GasUsed is the amount of gas that was used processing this transaction.
+        # If the transaction has not yet been mined, this field will be null.
+        gasUsed: Long
+        # CumulativeGasUsed is the total gas used in the block up to and including
+        # this transaction. If the transaction has not yet been mined, this field
+        # will be null.
+        cumulativeGasUsed: Long
+        # CreatedContract is the account that was created by a contract creation
+        # transaction. If the transaction was not a contract creation transaction,
+        # or it has not yet been mined, this field will be null.
+        createdContract(block: Long): Account
+        # Logs is a list of log entries emitted by this transaction. If the
+        # transaction has not yet been mined, this field will be null.
+        logs: [Log!]
+        r: BigInt!
+        s: BigInt!
+        v: BigInt!
+    }
+
+    # BlockFilterCriteria encapsulates log filter criteria for a filter applied
+    # to a single block.
+    input BlockFilterCriteria {
+        # Addresses is list of addresses that are of interest. If this list is
+        # empty, results will not be filtered by address.
+        addresses: [Address!]
+        # Topics list restricts matches to particular event topics. Each event has a list
+      # of topics. Topics matches a prefix of that list. An empty element array matches any
+      # topic. Non-empty elements represent an alternative that matches any of the
+      # contained topics.
+      #
+      # Examples:
+      #  - [] or nil          matches any topic list
+      #  - [[A]]              matches topic A in first position
+      #  - [[], [B]]          matches any topic in first position, B in second position
+      #  - [[A], [B]]         matches topic A in first position, B in second position
+      #  - [[A, B]], [C, D]]  matches topic (A OR B) in first position, (C OR D) in second position
+        topics: [[Bytes32!]!]
+    }
+
+    # Block is an Ethereum block.
+    type Block {
+        # Number is the number of this block, starting at 0 for the genesis block.
+        number: Long!
+        # Hash is the block hash of this block.
+        hash: Bytes32!
+        # Parent is the parent block of this block.
+        parent: Block
+        # Nonce is the block nonce, an 8 byte sequence determined by the miner.
+        nonce: Bytes!
+        # TransactionsRoot is the keccak256 hash of the root of the trie of transactions in this block.
+        transactionsRoot: Bytes32!
+        # TransactionCount is the number of transactions in this block. if
+        # transactions are not available for this block, this field will be null.
+        transactionCount: Int
+        # StateRoot is the keccak256 hash of the state trie after this block was processed.
+        stateRoot: Bytes32!
+        # ReceiptsRoot is the keccak256 hash of the trie of transaction receipts in this block.
+        receiptsRoot: Bytes32!
+        # Miner is the account that mined this block.
+        miner(block: Long): Account!
+        # ExtraData is an arbitrary data field supplied by the miner.
+        extraData: Bytes!
+        # GasLimit is the maximum amount of gas that was available to transactions in this block.
+        gasLimit: Long!
+        # GasUsed is the amount of gas that was used executing transactions in this block.
+        gasUsed: Long!
+        # Timestamp is the unix timestamp at which this block was mined.
+        timestamp: Long!
+        # LogsBloom is a bloom filter that can be used to check if a block may
+        # contain log entries matching a filter.
+        logsBloom: Bytes!
+        # MixHash is the hash that was used as an input to the PoW process.
+        mixHash: Bytes32!
+        # Difficulty is a measure of the difficulty of mining this block.
+        difficulty: BigInt!
+        # TotalDifficulty is the sum of all difficulty values up to and including
+        # this block.
+        totalDifficulty: BigInt!
+        # OmmerCount is the number of ommers (AKA uncles) associated with this
+        # block. If ommers are unavailable, this field will be null.
+        ommerCount: Int
+        # Ommers is a list of ommer (AKA uncle) blocks associated with this block.
+        # If ommers are unavailable, this field will be null. Depending on your
+        # node, the transactions, transactionAt, transactionCount, ommers,
+        # ommerCount and ommerAt fields may not be available on any ommer blocks.
+        ommers: [Block]
+        # OmmerAt returns the ommer (AKA uncle) at the specified index. If ommers
+        # are unavailable, or the index is out of bounds, this field will be null.
+        ommerAt(index: Int!): Block
+        # OmmerHash is the keccak256 hash of all the ommers (AKA uncles)
+        # associated with this block.
+        ommerHash: Bytes32!
+        # Transactions is a list of transactions associated with this block. If
+        # transactions are unavailable for this block, this field will be null.
+        transactions: [Transaction!]
+        # TransactionAt returns the transaction at the specified index. If
+        # transactions are unavailable for this block, or if the index is out of
+        # bounds, this field will be null.
+        transactionAt(index: Int!): Transaction
+        # Logs returns a filtered set of logs from this block.
+        logs(filter: BlockFilterCriteria!): [Log!]!
+        # Account fetches an Ethereum account at the current block's state.
+        account(address: Address!): Account!
+        # Call executes a local call operation at the current block's state.
+        call(data: CallData!): CallResult
+    }
+
+    # CallData represents the data associated with a local contract call.
+    # All fields are optional.
+    input CallData {
+        # From is the address making the call.
+        from: Address
+        # To is the address the call is sent to.
+        to: Address
+        # Gas is the amount of gas sent with the call.
+        gas: Long
+        # GasPrice is the price, in wei, offered for each unit of gas.
+        gasPrice: BigInt
+        # Value is the value, in wei, sent along with the call.
+        value: BigInt
+        # Data is the data sent to the callee.
+        data: Bytes
+    }
+
+    # CallResult is the result of a local call operation.
+    type CallResult {
+        # Data is the return data of the called contract.
+        data: Bytes!
+        # GasUsed is the amount of gas used by the call, after any refunds.
+        gasUsed: Long!
+        # Status is the result of the call - 1 for success or 0 for failure.
+        status: Long!
+    }
+
+    # FilterCriteria encapsulates log filter criteria for searching log entries.
+    input FilterCriteria {
+        # FromBlock is the block at which to start searching, inclusive. Defaults
+        # to the latest block if not supplied.
+        fromBlock: Long
+        # ToBlock is the block at which to stop searching, inclusive. Defaults
+        # to the latest block if not supplied.
+        toBlock: Long
+        # Addresses is a list of addresses that are of interest. If this list is
+        # empty, results will not be filtered by address.
+        addresses: [Address!]
+        # Topics list restricts matches to particular event topics. Each event has a list
+      # of topics. Topics matches a prefix of that list. An empty element array matches any
+      # topic. Non-empty elements represent an alternative that matches any of the
+      # contained topics.
+      #
+      # Examples:
+      #  - [] or nil          matches any topic list
+      #  - [[A]]              matches topic A in first position
+      #  - [[], [B]]          matches any topic in first position, B in second position
+      #  - [[A], [B]]         matches topic A in first position, B in second position
+      #  - [[A, B]], [C, D]]  matches topic (A OR B) in first position, (C OR D) in second position
+        topics: [[Bytes32!]!]
+    }
+
+    type Query {
+        # Block fetches an Ethereum block by number or by hash. If neither is
+        # supplied, the most recent known block is returned.
+        block(number: Long, hash: Bytes32): Block
+        # Blocks returns all the blocks between two numbers, inclusive. If
+        # to is not supplied, it defaults to the most recent known block.
+        blocks(from: Long!, to: Long): [Block!]!
+        # Transaction returns a transaction specified by its hash.
+        transaction(hash: Bytes32!): Transaction
+        # Logs returns log entries matching the provided filter.
+        logs(filter: FilterCriteria!): [Log!]!
+    }
+`

pkg/graphql/service.go

@@ -0,0 +1,104 @@
+// VulcanizeDB
+// Copyright © 2020 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 graphql
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/graph-gophers/graphql-go"
+	"github.com/graph-gophers/graphql-go/relay"
+	"github.com/sirupsen/logrus"
+
+	"github.com/vulcanize/ipld-eth-server/pkg/eth"
+)
+
+// Service encapsulates a GraphQL service.
+type Service struct {
+	endpoint string           // The host:port endpoint for this service.
+	cors     []string         // Allowed CORS domains
+	vhosts   []string         // Recognised vhosts
+	timeouts rpc.HTTPTimeouts // Timeout settings for HTTP requests.
+	backend  *eth.Backend     // The backend that queries will operate onn.
+	handler  http.Handler     // The `http.Handler` used to answer queries.
+	listener net.Listener     // The listening socket.
+}
+
+// New constructs a new GraphQL service instance.
+func New(backend *eth.Backend, endpoint string, cors, vhosts []string, timeouts rpc.HTTPTimeouts) (*Service, error) {
+	return &Service{
+		endpoint: endpoint,
+		cors:     cors,
+		vhosts:   vhosts,
+		timeouts: timeouts,
+		backend:  backend,
+	}, nil
+}
+
+// Protocols returns the list of protocols exported by this service.
+func (s *Service) Protocols() []p2p.Protocol { return nil }
+
+// APIs returns the list of APIs exported by this service.
+func (s *Service) APIs() []rpc.API { return nil }
+
+// Start is called after all services have been constructed and the networking
+// layer was also initialized to spawn any goroutines required by the service.
+func (s *Service) Start(server *p2p.Server) error {
+	var err error
+	s.handler, err = NewHandler(s.backend)
+	if err != nil {
+		return err
+	}
+	if s.listener, err = net.Listen("tcp", s.endpoint); err != nil {
+		return err
+	}
+	go rpc.NewHTTPServer(s.cors, s.vhosts, s.timeouts, s.handler).Serve(s.listener)
+	logrus.Debugf("graphQL endpoint opened for url %s", fmt.Sprintf("http://%s", s.endpoint))
+	return nil
+}
+
+// newHandler returns a new `http.Handler` that will answer GraphQL queries.
+// It additionally exports an interactive query browser on the / endpoint.
+func NewHandler(backend *eth.Backend) (http.Handler, error) {
+	q := Resolver{backend}
+
+	s, err := graphql.ParseSchema(schema, &q)
+	if err != nil {
+		return nil, err
+	}
+	h := &relay.Handler{Schema: s}
+
+	mux := http.NewServeMux()
+	mux.Handle("/", GraphiQL{})
+	mux.Handle("/graphql", h)
+	mux.Handle("/graphql/", h)
+	return mux, nil
+}
+
+// Stop terminates all goroutines belonging to the service, blocking until they
+// are all terminated.
+func (s *Service) Stop() error {
+	if s.listener != nil {
+		s.listener.Close()
+		s.listener = nil
+		logrus.Debugf("graphQL endpoint closed for url %s", fmt.Sprintf("http://%s", s.endpoint))
+	}
+	return nil
+}

pkg/serve/service.go

@@ -52,6 +52,8 @@ type Server interface {
 	Subscribe(id rpc.ID, sub chan<- SubscriptionPayload, quitChan chan<- bool, params eth.SubscriptionSettings)
 	// Method to unsubscribe from the service
 	Unsubscribe(id rpc.ID)
+	// Backend exposes the server's backend
+	Backend() *eth.Backend
 }
 
 // Service is the underlying struct for the watcher
@@ -74,29 +76,30 @@ type Service struct {
 	db *postgres.DB
 	// wg for syncing serve processes
 	serveWg *sync.WaitGroup
-	// config for backend
-	config *eth.Config
 	// rpc client for forwarding cache misses
 	client *rpc.Client
+	// backend for the server
+	backend *eth.Backend
 }
 
 // NewServer creates a new Server using an underlying Service struct
 func NewServer(settings *Config) (Server, error) {
-	sn := new(Service)
+	sap := new(Service)
-	sn.Retriever = eth.NewCIDRetriever(settings.DB)
+	sap.Retriever = eth.NewCIDRetriever(settings.DB)
-	sn.IPLDFetcher = eth.NewIPLDFetcher(settings.DB)
+	sap.IPLDFetcher = eth.NewIPLDFetcher(settings.DB)
-	sn.Filterer = eth.NewResponseFilterer()
+	sap.Filterer = eth.NewResponseFilterer()
-	sn.db = settings.DB
+	sap.db = settings.DB
-	sn.QuitChan = make(chan bool)
+	sap.QuitChan = make(chan bool)
-	sn.Subscriptions = make(map[common.Hash]map[rpc.ID]Subscription)
+	sap.Subscriptions = make(map[common.Hash]map[rpc.ID]Subscription)
-	sn.SubscriptionTypes = make(map[common.Hash]eth.SubscriptionSettings)
+	sap.SubscriptionTypes = make(map[common.Hash]eth.SubscriptionSettings)
-	sn.config = &eth.Config{
+	var err error
+	sap.backend, err = eth.NewEthBackend(sap.db, &eth.Config{
 		ChainConfig:   settings.ChainConfig,
 		VmConfig:      vm.Config{},
 		DefaultSender: settings.DefaultSender,
 		RPCGasCap:     settings.RPCGasCap,
-	}
+	})
-	return sn, nil
+	return sap, err
 }
 
 // Protocols exports the services p2p protocols, this service has none
@@ -133,15 +136,10 @@ func (sap *Service) APIs() []rpc.API {
 			Public:    true,
 		},
 	}
-	backend, err := eth.NewEthBackend(sap.db, sap.config)
-	if err != nil {
-		log.Error(err)
-		return nil
-	}
 	return append(apis, rpc.API{
 		Namespace: eth.APIName,
 		Version:   eth.APIVersion,
-		Service:   eth.NewPublicEthAPI(backend, sap.client),
+		Service:   eth.NewPublicEthAPI(sap.backend, sap.client),
 		Public:    true,
 	})
 }
@@ -358,6 +356,11 @@ func (sap *Service) Stop() error {
 	return nil
 }
 
+// Backend exposes the server's backend
+func (sap *Service) Backend() *eth.Backend {
+	return sap.backend
+}
+
 // close is used to close all listening subscriptions
 // close needs to be called with subscription access locked
 func (sap *Service) close() {