eth, internal/ethapi, internal/web3ext: add eth_historicalGasPrice RPC

eth/api_backend.go

@@ -279,6 +279,10 @@ func (b *EthAPIBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
 	return b.gpo.SuggestPrice(ctx)
 }
 
+func (b *EthAPIBackend) SuggestedPrice(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*big.Int, error) {
+	return b.gpo.SuggestPrice(ctx)
+}
+
 func (b *EthAPIBackend) ChainDb() ethdb.Database {
 	return b.eth.ChainDb()
 }

eth/gasprice/gasprice.go

@@ -43,6 +43,7 @@ type Config struct {
 // OracleBackend includes all necessary background APIs for oracle.
 type OracleBackend interface {
 	HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error)
+	HeaderByNumberOrHash(ctx context.Context, number rpc.BlockNumberOrHash) (*types.Header, error)
 	BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
 	ChainConfig() *params.ChainConfig
 }
@@ -95,7 +96,11 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 // SuggestPrice returns a gasprice so that newly created transaction can
 // have a very high chance to be included in the following blocks.
 func (gpo *Oracle) SuggestPrice(ctx context.Context) (*big.Int, error) {
-	head, _ := gpo.backend.HeaderByNumber(ctx, rpc.LatestBlockNumber)
+	return gpo.SuggestedPrice(ctx, rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber))
+}
+
+func (gpo *Oracle) SuggestedPrice(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*big.Int, error) {
+	head, _ := gpo.backend.HeaderByNumberOrHash(ctx, blockNrOrHash)
 	headHash := head.Hash()
 
 	// If the latest gasprice is still available, return it.

internal/ethapi/api.go

@@ -65,6 +65,12 @@ func (s *PublicEthereumAPI) GasPrice(ctx context.Context) (*hexutil.Big, error)
 	return (*hexutil.Big)(price), err
 }
 
+// GasPrice returns a suggestion for a gas price.
+func (s *PublicEthereumAPI) HistoricalGasPrice(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*hexutil.Big, error) {
+	price, err := s.b.SuggestedPrice(ctx, blockNrOrHash)
+	return (*hexutil.Big)(price), err
+}
+
 // Syncing returns false in case the node is currently not syncing with the network. It can be up to date or has not
 // yet received the latest block headers from its pears. In case it is synchronizing:
 // - startingBlock: block number this node started to synchronise from

internal/ethapi/backend.go

@@ -42,6 +42,7 @@ type Backend interface {
 	// General Ethereum API
 	Downloader() *downloader.Downloader
 	SuggestPrice(ctx context.Context) (*big.Int, error)
+	SuggestedPrice(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*big.Int, error)
 	ChainDb() ethdb.Database
 	AccountManager() *accounts.Manager
 	ExtRPCEnabled() bool

internal/web3ext/web3ext.go

@@ -581,6 +581,12 @@ web3._extend({
 			params: 2,
 			inputFormatter: [null, web3._extend.formatters.inputBlockNumberFormatter],
 		}),
+		new web3._extend.Method({
+			name: 'historicalGasPrice',
+			call: 'eth_historicalGasPrice',
+			params: 1,
+			inputFormatter: [web3._extend.formatters.inputBlockNumberFormatter]
+		}),
 	],
 	properties: [
 		new web3._extend.Property({

les/api_backend.go

@@ -255,6 +255,10 @@ func (b *LesApiBackend) SuggestPrice(ctx context.Context) (*big.Int, error) {
 	return b.gpo.SuggestPrice(ctx)
 }
 
+func (b *LesApiBackend) SuggestedPrice(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*big.Int, error) {
+	return nil, errors.New("not implemented")
+}
+
 func (b *LesApiBackend) ChainDb() ethdb.Database {
 	return b.eth.chainDb
 }