laconicd/ethereum/rpc/websockets.go

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package rpc
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"math/big"
"net/http"
"sync"
"github.com/gorilla/mux"
"github.com/gorilla/websocket"
"github.com/pkg/errors"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/eth/filters"
"github.com/ethereum/go-ethereum/rpc"
"github.com/tendermint/tendermint/libs/log"
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coretypes "github.com/tendermint/tendermint/rpc/core/types"
rpcclient "github.com/tendermint/tendermint/rpc/jsonrpc/client"
tmtypes "github.com/tendermint/tendermint/types"
rpcfilters "github.com/tharsis/ethermint/ethereum/rpc/namespaces/eth/filters"
"github.com/tharsis/ethermint/ethereum/rpc/types"
evmtypes "github.com/tharsis/ethermint/x/evm/types"
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)
type WebsocketsServer interface {
Start()
}
type SubscriptionResponseJSON struct {
Jsonrpc string `json:"jsonrpc"`
Result interface{} `json:"result"`
ID float64 `json:"id"`
}
type SubscriptionNotification struct {
Jsonrpc string `json:"jsonrpc"`
Method string `json:"method"`
Params *SubscriptionResult `json:"params"`
}
type SubscriptionResult struct {
Subscription rpc.ID `json:"subscription"`
Result interface{} `json:"result"`
}
type ErrorResponseJSON struct {
Jsonrpc string `json:"jsonrpc"`
Error *ErrorMessageJSON `json:"error"`
ID *big.Int `json:"id"`
}
type ErrorMessageJSON struct {
Code *big.Int `json:"code"`
Message string `json:"message"`
}
type websocketsServer struct {
rpcAddr string // listen address of rest-server
wsAddr string // listen address of ws server
api *pubSubAPI
logger log.Logger
}
func NewWebsocketsServer(logger log.Logger, tmWSClient *rpcclient.WSClient, rpcAddr, wsAddr string) WebsocketsServer {
logger = logger.With("module", "websocket-server")
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return &websocketsServer{
rpcAddr: rpcAddr,
wsAddr: wsAddr,
api: newPubSubAPI(logger, tmWSClient),
logger: logger,
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}
}
func (s *websocketsServer) Start() {
ws := mux.NewRouter()
ws.Handle("/", s)
go func() {
err := http.ListenAndServe(s.wsAddr, ws)
if err != nil {
if err == http.ErrServerClosed {
return
}
s.logger.Error("failed to start HTTP server for WS", "error", err.Error())
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}
}()
}
func (s *websocketsServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
var upgrader = websocket.Upgrader{
CheckOrigin: func(r *http.Request) bool {
return true
},
}
conn, err := upgrader.Upgrade(w, r, nil)
if err != nil {
s.logger.Debug("websocket upgrade failed", "error", err.Error())
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return
}
s.readLoop(&wsConn{
mux: new(sync.Mutex),
conn: conn,
})
}
func (s *websocketsServer) sendErrResponse(wsConn *wsConn, msg string) {
res := &ErrorResponseJSON{
Jsonrpc: "2.0",
Error: &ErrorMessageJSON{
Code: big.NewInt(-32600),
Message: msg,
},
ID: nil,
}
_ = wsConn.WriteJSON(res)
}
type wsConn struct {
conn *websocket.Conn
mux *sync.Mutex
}
func (w *wsConn) WriteJSON(v interface{}) error {
w.mux.Lock()
defer w.mux.Unlock()
return w.conn.WriteJSON(v)
}
func (w *wsConn) Close() error {
w.mux.Lock()
defer w.mux.Unlock()
return w.conn.Close()
}
func (w *wsConn) ReadMessage() (messageType int, p []byte, err error) {
// not protected by write mutex
return w.conn.ReadMessage()
}
func (s *websocketsServer) readLoop(wsConn *wsConn) {
for {
_, mb, err := wsConn.ReadMessage()
if err != nil {
_ = wsConn.Close()
return
}
var msg map[string]interface{}
err = json.Unmarshal(mb, &msg)
if err != nil {
s.sendErrResponse(wsConn, "invalid request")
continue
}
// check if method == eth_subscribe or eth_unsubscribe
method, ok := msg["method"].(string)
if !ok {
// otherwise, call the usual rpc server to respond
err = s.tcpGetAndSendResponse(wsConn, mb)
if err != nil {
s.sendErrResponse(wsConn, err.Error())
}
continue
}
connID := msg["id"].(float64)
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if method == "eth_subscribe" {
params := msg["params"].([]interface{})
if len(params) == 0 {
s.sendErrResponse(wsConn, "invalid parameters")
continue
}
id, err := s.api.subscribe(wsConn, params)
if err != nil {
s.sendErrResponse(wsConn, err.Error())
continue
}
res := &SubscriptionResponseJSON{
Jsonrpc: "2.0",
ID: connID,
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Result: id,
}
err = wsConn.WriteJSON(res)
if err != nil {
continue
}
continue
} else if method == "eth_unsubscribe" {
ids, ok := msg["params"].([]interface{})
if _, idok := ids[0].(string); !ok || !idok {
s.sendErrResponse(wsConn, "invalid parameters")
continue
}
ok = s.api.unsubscribe(rpc.ID(ids[0].(string)))
res := &SubscriptionResponseJSON{
Jsonrpc: "2.0",
ID: connID,
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Result: ok,
}
err = wsConn.WriteJSON(res)
if err != nil {
continue
}
continue
}
// otherwise, call the usual rpc server to respond
err = s.tcpGetAndSendResponse(wsConn, mb)
if err != nil {
s.sendErrResponse(wsConn, err.Error())
}
}
}
// tcpGetAndSendResponse connects to the rest-server over tcp, posts a JSON-RPC request, and sends the response
// to the client over websockets
func (s *websocketsServer) tcpGetAndSendResponse(wsConn *wsConn, mb []byte) error {
req, err := http.NewRequest("POST", "http://"+s.rpcAddr, bytes.NewBuffer(mb))
if err != nil {
return errors.Wrap(err, "Could not build request")
}
req.Header.Set("Content-Type", "application/json")
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
return errors.Wrap(err, "Could not perform request")
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return errors.Wrap(err, "could not read body from response")
}
var wsSend interface{}
err = json.Unmarshal(body, &wsSend)
if err != nil {
return errors.Wrap(err, "failed to unmarshal rest-server response")
}
return wsConn.WriteJSON(wsSend)
}
type wsSubscription struct {
sub *rpcfilters.Subscription
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unsubscribed chan struct{} // closed when unsubscribing
wsConn *wsConn
query string
}
// pubSubAPI is the eth_ prefixed set of APIs in the Web3 JSON-RPC spec
type pubSubAPI struct {
events *rpcfilters.EventSystem
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filtersMu *sync.RWMutex
filters map[rpc.ID]*wsSubscription
logger log.Logger
}
// newPubSubAPI creates an instance of the ethereum PubSub API.
func newPubSubAPI(logger log.Logger, tmWSClient *rpcclient.WSClient) *pubSubAPI {
logger = logger.With("module", "websocket-client")
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return &pubSubAPI{
events: rpcfilters.NewEventSystem(logger, tmWSClient),
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filtersMu: new(sync.RWMutex),
filters: make(map[rpc.ID]*wsSubscription),
logger: logger,
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}
}
func (api *pubSubAPI) subscribe(wsConn *wsConn, params []interface{}) (rpc.ID, error) {
method, ok := params[0].(string)
if !ok {
return "0", errors.New("invalid parameters")
}
switch method {
case "newHeads":
// TODO: handle extra params
return api.subscribeNewHeads(wsConn)
case "logs":
if len(params) > 1 {
return api.subscribeLogs(wsConn, params[1])
}
return api.subscribeLogs(wsConn, nil)
case "newPendingTransactions":
return api.subscribePendingTransactions(wsConn)
case "syncing":
return api.subscribeSyncing(wsConn)
default:
return "0", errors.Errorf("unsupported method %s", method)
}
}
func (api *pubSubAPI) unsubscribe(id rpc.ID) bool {
api.filtersMu.Lock()
defer api.filtersMu.Unlock()
wsSub, ok := api.filters[id]
if !ok {
return false
}
wsSub.sub.Unsubscribe(api.events)
close(api.filters[id].unsubscribed)
delete(api.filters, id)
return true
}
func (api *pubSubAPI) subscribeNewHeads(wsConn *wsConn) (rpc.ID, error) {
var query = "subscribeNewHeads"
var subID = rpc.NewID()
sub, _, err := api.events.SubscribeNewHeads()
if err != nil {
return "", errors.Wrap(err, "error creating block filter")
}
unsubscribed := make(chan struct{})
api.filtersMu.Lock()
api.filters[subID] = &wsSubscription{
sub: sub,
wsConn: wsConn,
unsubscribed: unsubscribed,
query: query,
}
api.filtersMu.Unlock()
go func(headersCh <-chan coretypes.ResultEvent, errCh <-chan error) {
for {
select {
case event, ok := <-headersCh:
if !ok {
api.unsubscribe(subID)
return
}
data, ok := event.Data.(tmtypes.EventDataNewBlockHeader)
if !ok {
api.logger.Debug("event data type mismatch", "type", fmt.Sprintf("%T", event.Data))
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continue
}
header := types.EthHeaderFromTendermint(data.Header)
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api.filtersMu.RLock()
for subID, wsSub := range api.filters {
subID := subID
wsSub := wsSub
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if wsSub.query != query {
continue
}
// write to ws conn
res := &SubscriptionNotification{
Jsonrpc: "2.0",
Method: "eth_subscription",
Params: &SubscriptionResult{
Subscription: subID,
Result: header,
},
}
err = wsSub.wsConn.WriteJSON(res)
if err != nil {
api.logger.Error("error writing header, will drop peer", "error", err.Error())
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try(func() {
api.filtersMu.RUnlock()
api.filtersMu.Lock()
defer func() {
api.filtersMu.Unlock()
api.filtersMu.RLock()
}()
if err != websocket.ErrCloseSent {
_ = wsSub.wsConn.Close()
}
delete(api.filters, subID)
close(wsSub.unsubscribed)
}, api.logger, "closing websocket peer sub")
}
}
api.filtersMu.RUnlock()
case err, ok := <-errCh:
if !ok {
api.unsubscribe(subID)
return
}
api.logger.Debug("dropping NewHeads WebSocket subscription", "subscription-id", subID, "error", err.Error())
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api.unsubscribe(subID)
case <-unsubscribed:
return
}
}
}(sub.Event(), sub.Err())
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return subID, nil
}
func try(fn func(), l log.Logger, desc string) {
defer func() {
if x := recover(); x != nil {
if err, ok := x.(error); ok {
// debug.PrintStack()
l.Debug("panic during "+desc, "error", err.Error())
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return
}
l.Debug(fmt.Sprintf("panic during %s: %+v", desc, x))
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return
}
}()
fn()
}
func (api *pubSubAPI) subscribeLogs(wsConn *wsConn, extra interface{}) (rpc.ID, error) {
crit := filters.FilterCriteria{}
if extra != nil {
params, ok := extra.(map[string]interface{})
if !ok {
err := errors.New("invalid criteria")
api.logger.Debug("invalid criteria", "type", fmt.Sprintf("%T", extra))
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return "", err
}
if params["address"] != nil {
address, ok := params["address"].(string)
addresses, sok := params["address"].([]interface{})
if !ok && !sok {
err := errors.New("invalid addresses; must be address or array of addresses")
api.logger.Debug("invalid addresses", "type", fmt.Sprintf("%T", params["address"]))
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return "", err
}
if ok {
crit.Addresses = []common.Address{common.HexToAddress(address)}
}
if sok {
crit.Addresses = []common.Address{}
for _, addr := range addresses {
address, ok := addr.(string)
if !ok {
err := errors.New("invalid address")
api.logger.Debug("invalid address", "type", fmt.Sprintf("%T", addr))
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return "", err
}
crit.Addresses = append(crit.Addresses, common.HexToAddress(address))
}
}
}
if params["topics"] != nil {
topics, ok := params["topics"].([]interface{})
if !ok {
err := errors.Errorf("invalid topics: %s", topics)
api.logger.Error("invalid topics", "type", fmt.Sprintf("%T", topics))
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return "", err
}
crit.Topics = make([][]common.Hash, len(topics))
addCritTopic := func(topicIdx int, topic interface{}) error {
tstr, ok := topic.(string)
if !ok {
err := errors.Errorf("invalid topic: %s", topic)
api.logger.Error("invalid topic", "type", fmt.Sprintf("%T", topic))
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return err
}
crit.Topics[topicIdx] = []common.Hash{common.HexToHash(tstr)}
return nil
}
for topicIdx, subtopics := range topics {
if subtopics == nil {
continue
}
// in case we don't have list, but a single topic value
if topic, ok := subtopics.(string); ok {
if err := addCritTopic(topicIdx, topic); err != nil {
return "", err
}
continue
}
// in case we actually have a list of subtopics
subtopicsList, ok := subtopics.([]interface{})
if !ok {
err := errors.New("invalid subtopics")
api.logger.Error("invalid subtopic", "type", fmt.Sprintf("%T", subtopics))
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return "", err
}
subtopicsCollect := make([]common.Hash, len(subtopicsList))
for idx, subtopic := range subtopicsList {
tstr, ok := subtopic.(string)
if !ok {
err := errors.Errorf("invalid subtopic: %s", subtopic)
api.logger.Error("invalid subtopic", "type", fmt.Sprintf("%T", subtopic))
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return "", err
}
subtopicsCollect[idx] = common.HexToHash(tstr)
}
crit.Topics[topicIdx] = subtopicsCollect
}
}
}
critBz, err := json.Marshal(crit)
if err != nil {
api.logger.Error("failed to JSON marshal criteria", "error", err.Error())
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return rpc.ID(""), err
}
var query = "subscribeLogs" + string(critBz)
var subID = rpc.NewID()
sub, _, err := api.events.SubscribeLogs(crit)
if err != nil {
api.logger.Error("failed to subscribe logs", "error", err.Error())
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return rpc.ID(""), err
}
unsubscribed := make(chan struct{})
api.filtersMu.Lock()
api.filters[subID] = &wsSubscription{
sub: sub,
wsConn: wsConn,
unsubscribed: unsubscribed,
query: query,
}
api.filtersMu.Unlock()
go func(ch <-chan coretypes.ResultEvent, errCh <-chan error, subID rpc.ID) {
for {
select {
case event, ok := <-ch:
if !ok {
api.unsubscribe(subID)
return
}
dataTx, ok := event.Data.(tmtypes.EventDataTx)
if !ok {
api.logger.Debug("event data type mismatch", "type", fmt.Sprintf("%T", event.Data))
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continue
}
txResponse, err := evmtypes.DecodeTxResponse(dataTx.TxResult.Result.Data)
if err != nil {
api.logger.Error("failed to decode tx response", "error", err.Error())
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return
}
logs := rpcfilters.FilterLogs(evmtypes.LogsToEthereum(txResponse.Logs), crit.FromBlock, crit.ToBlock, crit.Addresses, crit.Topics)
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if len(logs) == 0 {
continue
}
api.filtersMu.RLock()
wsSub, ok := api.filters[subID]
if !ok {
api.logger.Debug("subID not in filters", subID)
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return
}
api.filtersMu.RUnlock()
for _, ethLog := range logs {
res := &SubscriptionNotification{
Jsonrpc: "2.0",
Method: "eth_subscription",
Params: &SubscriptionResult{
Subscription: subID,
Result: ethLog,
},
}
err = wsSub.wsConn.WriteJSON(res)
if err != nil {
try(func() {
api.filtersMu.Lock()
defer api.filtersMu.Unlock()
if err != websocket.ErrCloseSent {
_ = wsSub.wsConn.Close()
}
delete(api.filters, subID)
close(wsSub.unsubscribed)
}, api.logger, "closing websocket peer sub")
}
}
case err, ok := <-errCh:
if !ok {
api.unsubscribe(subID)
return
}
api.logger.Debug("dropping Logs WebSocket subscription", "subscription-id", subID, "error", err.Error())
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api.unsubscribe(subID)
case <-unsubscribed:
return
}
}
}(sub.Event(), sub.Err(), subID)
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return subID, nil
}
func (api *pubSubAPI) subscribePendingTransactions(wsConn *wsConn) (rpc.ID, error) {
var query = "subscribePendingTransactions"
var subID = rpc.NewID()
sub, _, err := api.events.SubscribePendingTxs()
if err != nil {
return "", errors.Wrap(err, "error creating block filter: %s")
}
unsubscribed := make(chan struct{})
api.filtersMu.Lock()
api.filters[subID] = &wsSubscription{
sub: sub,
wsConn: wsConn,
unsubscribed: unsubscribed,
query: query,
}
api.filtersMu.Unlock()
go func(txsCh <-chan coretypes.ResultEvent, errCh <-chan error) {
for {
select {
case ev := <-txsCh:
data, _ := ev.Data.(tmtypes.EventDataTx)
txHash := common.BytesToHash(tmtypes.Tx(data.Tx).Hash())
api.filtersMu.RLock()
for subID, wsSub := range api.filters {
subID := subID
wsSub := wsSub
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if wsSub.query != query {
continue
}
// write to ws conn
res := &SubscriptionNotification{
Jsonrpc: "2.0",
Method: "eth_subscription",
Params: &SubscriptionResult{
Subscription: subID,
Result: txHash,
},
}
err = wsSub.wsConn.WriteJSON(res)
if err != nil {
api.logger.Debug("error writing header, will drop peer", "error", err.Error())
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try(func() {
api.filtersMu.Lock()
defer api.filtersMu.Unlock()
if err != websocket.ErrCloseSent {
_ = wsSub.wsConn.Close()
}
delete(api.filters, subID)
close(wsSub.unsubscribed)
}, api.logger, "closing websocket peer sub")
}
}
api.filtersMu.RUnlock()
case err, ok := <-errCh:
if !ok {
api.unsubscribe(subID)
return
}
api.logger.Debug("dropping PendingTransactions WebSocket subscription", subID, "error", err.Error())
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api.unsubscribe(subID)
case <-unsubscribed:
return
}
}
}(sub.Event(), sub.Err())
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return subID, nil
}
func (api *pubSubAPI) subscribeSyncing(wsConn *wsConn) (rpc.ID, error) {
return "", nil
}