neoneo-go/pkg/rpc/client/wsclient.go
AnnaShaleva 0d8723527c rpc: refactor WSClient initialisation
Fix the following linter warning:
```
pkg/rpc/client/wsclient.go:99:18  govet  copylocks: literal copies lock value from *cl: github.com/nspcc-dev/neo-go/pkg/rpc/client.Client contains sync.RWMutex
```
2022-02-24 19:01:21 +03:00

393 lines
12 KiB
Go

package client
import (
"context"
"encoding/json"
"errors"
"strconv"
"sync"
"time"
"github.com/gorilla/websocket"
"github.com/nspcc-dev/neo-go/pkg/core/block"
"github.com/nspcc-dev/neo-go/pkg/core/state"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/rpc/request"
"github.com/nspcc-dev/neo-go/pkg/rpc/response"
"github.com/nspcc-dev/neo-go/pkg/rpc/response/result/subscriptions"
"github.com/nspcc-dev/neo-go/pkg/util"
)
// WSClient is a websocket-enabled RPC client that can be used with appropriate
// servers. It's supposed to be faster than Client because it has persistent
// connection to the server and at the same time is exposes some functionality
// that is only provided via websockets (like event subscription mechanism).
type WSClient struct {
Client
// Notifications is a channel that is used to send events received from
// server. Client's code is supposed to be reading from this channel if
// it wants to use subscription mechanism, failing to do so will cause
// WSClient to block even regular requests. This channel is not buffered.
// In case of protocol error or upon connection closure this channel will
// be closed, so make sure to handle this.
Notifications chan Notification
ws *websocket.Conn
done chan struct{}
requests chan *request.Raw
shutdown chan struct{}
subscriptionsLock sync.RWMutex
subscriptions map[string]bool
respLock sync.RWMutex
respChannels map[uint64]chan *response.Raw
}
// Notification represents server-generated notification for client subscriptions.
// Value can be one of block.Block, state.AppExecResult, subscriptions.NotificationEvent
// transaction.Transaction or subscriptions.NotaryRequestEvent based on Type.
type Notification struct {
Type response.EventID
Value interface{}
}
// requestResponse is a combined type for request and response since we can get
// any of them here.
type requestResponse struct {
request.In
Error *response.Error `json:"error,omitempty"`
Result json.RawMessage `json:"result,omitempty"`
}
const (
// Message limit for receiving side.
wsReadLimit = 10 * 1024 * 1024
// Disconnection timeout.
wsPongLimit = 60 * time.Second
// Ping period for connection liveness check.
wsPingPeriod = wsPongLimit / 2
// Write deadline.
wsWriteLimit = wsPingPeriod / 2
)
// NewWS returns a new WSClient ready to use (with established websocket
// connection). You need to use websocket URL for it like `ws://1.2.3.4/ws`.
// You should call Init method to initialize network magic the client is
// operating on.
func NewWS(ctx context.Context, endpoint string, opts Options) (*WSClient, error) {
dialer := websocket.Dialer{HandshakeTimeout: opts.DialTimeout}
ws, _, err := dialer.Dial(endpoint, nil)
if err != nil {
return nil, err
}
wsc := &WSClient{
Client: Client{},
Notifications: make(chan Notification),
ws: ws,
shutdown: make(chan struct{}),
done: make(chan struct{}),
respChannels: make(map[uint64]chan *response.Raw),
requests: make(chan *request.Raw),
subscriptions: make(map[string]bool),
}
err = initClient(ctx, &wsc.Client, endpoint, opts)
if err != nil {
return nil, err
}
wsc.Client.cli = nil
go wsc.wsReader()
go wsc.wsWriter()
wsc.requestF = wsc.makeWsRequest
return wsc, nil
}
// Close closes connection to the remote side rendering this client instance
// unusable.
func (c *WSClient) Close() {
// Closing shutdown channel send signal to wsWriter to break out of the
// loop. In doing so it does ws.Close() closing the network connection
// which in turn makes wsReader receieve err from ws,ReadJSON() and also
// break out of the loop closing c.done channel in its shutdown sequence.
close(c.shutdown)
<-c.done
}
func (c *WSClient) wsReader() {
c.ws.SetReadLimit(wsReadLimit)
c.ws.SetPongHandler(func(string) error { return c.ws.SetReadDeadline(time.Now().Add(wsPongLimit)) })
readloop:
for {
rr := new(requestResponse)
err := c.ws.SetReadDeadline(time.Now().Add(wsPongLimit))
if err != nil {
break
}
err = c.ws.ReadJSON(rr)
if err != nil {
// Timeout/connection loss/malformed response.
break
}
if rr.RawID == nil && rr.Method != "" {
event, err := response.GetEventIDFromString(rr.Method)
if err != nil {
// Bad event received.
break
}
if event != response.MissedEventID && len(rr.RawParams) != 1 {
// Bad event received.
break
}
var val interface{}
switch event {
case response.BlockEventID:
sr, err := c.StateRootInHeader()
if err != nil {
// Client is not initialised.
break
}
val = block.New(sr)
case response.TransactionEventID:
val = &transaction.Transaction{}
case response.NotificationEventID:
val = new(subscriptions.NotificationEvent)
case response.ExecutionEventID:
val = new(state.AppExecResult)
case response.NotaryRequestEventID:
val = new(subscriptions.NotaryRequestEvent)
case response.MissedEventID:
// No value.
default:
// Bad event received.
break readloop
}
if event != response.MissedEventID {
err = json.Unmarshal(rr.RawParams[0].RawMessage, val)
if err != nil {
// Bad event received.
break
}
}
c.Notifications <- Notification{event, val}
} else if rr.RawID != nil && (rr.Error != nil || rr.Result != nil) {
resp := new(response.Raw)
resp.ID = rr.RawID
resp.JSONRPC = rr.JSONRPC
resp.Error = rr.Error
resp.Result = rr.Result
id, err := strconv.Atoi(string(resp.ID))
if err != nil {
break // Malformed response (invalid response ID).
}
ch := c.getResponseChannel(uint64(id))
if ch == nil {
break // Unknown response (unexpected response ID).
}
ch <- resp
} else {
// Malformed response, neither valid request, nor valid response.
break
}
}
close(c.done)
c.respLock.Lock()
for _, ch := range c.respChannels {
close(ch)
}
c.respChannels = nil
c.respLock.Unlock()
close(c.Notifications)
}
func (c *WSClient) wsWriter() {
pingTicker := time.NewTicker(wsPingPeriod)
defer c.ws.Close()
defer pingTicker.Stop()
for {
select {
case <-c.shutdown:
return
case <-c.done:
return
case req, ok := <-c.requests:
if !ok {
return
}
if err := c.ws.SetWriteDeadline(time.Now().Add(c.opts.RequestTimeout)); err != nil {
return
}
if err := c.ws.WriteJSON(req); err != nil {
return
}
case <-pingTicker.C:
if err := c.ws.SetWriteDeadline(time.Now().Add(wsWriteLimit)); err != nil {
return
}
if err := c.ws.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
return
}
}
}
}
func (c *WSClient) registerRespChannel(id uint64, ch chan *response.Raw) {
c.respLock.Lock()
defer c.respLock.Unlock()
c.respChannels[id] = ch
}
func (c *WSClient) unregisterRespChannel(id uint64) {
c.respLock.Lock()
defer c.respLock.Unlock()
if ch, ok := c.respChannels[id]; ok {
delete(c.respChannels, id)
close(ch)
}
}
func (c *WSClient) getResponseChannel(id uint64) chan *response.Raw {
c.respLock.RLock()
defer c.respLock.RUnlock()
return c.respChannels[id]
}
func (c *WSClient) makeWsRequest(r *request.Raw) (*response.Raw, error) {
ch := make(chan *response.Raw)
c.registerRespChannel(r.ID, ch)
select {
case <-c.done:
return nil, errors.New("connection lost before sending the request")
case c.requests <- r:
}
select {
case <-c.done:
return nil, errors.New("connection lost while waiting for the response")
case resp := <-ch:
c.unregisterRespChannel(r.ID)
return resp, nil
}
}
func (c *WSClient) performSubscription(params request.RawParams) (string, error) {
var resp string
if err := c.performRequest("subscribe", params, &resp); err != nil {
return "", err
}
c.subscriptionsLock.Lock()
defer c.subscriptionsLock.Unlock()
c.subscriptions[resp] = true
return resp, nil
}
func (c *WSClient) performUnsubscription(id string) error {
var resp bool
c.subscriptionsLock.Lock()
defer c.subscriptionsLock.Unlock()
if !c.subscriptions[id] {
return errors.New("no subscription with this ID")
}
if err := c.performRequest("unsubscribe", request.NewRawParams(id), &resp); err != nil {
return err
}
if !resp {
return errors.New("unsubscribe method returned false result")
}
delete(c.subscriptions, id)
return nil
}
// SubscribeForNewBlocks adds subscription for new block events to this instance
// of client. It can filtered by primary consensus node index, nil value doesn't
// add any filters.
func (c *WSClient) SubscribeForNewBlocks(primary *int) (string, error) {
params := request.NewRawParams("block_added")
if primary != nil {
params.Values = append(params.Values, request.BlockFilter{Primary: *primary})
}
return c.performSubscription(params)
}
// SubscribeForNewTransactions adds subscription for new transaction events to
// this instance of client. It can be filtered by sender and/or signer, nil
// value is treated as missing filter.
func (c *WSClient) SubscribeForNewTransactions(sender *util.Uint160, signer *util.Uint160) (string, error) {
params := request.NewRawParams("transaction_added")
if sender != nil || signer != nil {
params.Values = append(params.Values, request.TxFilter{Sender: sender, Signer: signer})
}
return c.performSubscription(params)
}
// SubscribeForExecutionNotifications adds subscription for notifications
// generated during transaction execution to this instance of client. It can be
// filtered by contract's hash (that emits notifications), nil value puts no such
// restrictions.
func (c *WSClient) SubscribeForExecutionNotifications(contract *util.Uint160, name *string) (string, error) {
params := request.NewRawParams("notification_from_execution")
if contract != nil || name != nil {
params.Values = append(params.Values, request.NotificationFilter{Contract: contract, Name: name})
}
return c.performSubscription(params)
}
// SubscribeForTransactionExecutions adds subscription for application execution
// results generated during transaction execution to this instance of client. Can
// be filtered by state (HALT/FAULT) to check for successful or failing
// transactions, nil value means no filtering.
func (c *WSClient) SubscribeForTransactionExecutions(state *string) (string, error) {
params := request.NewRawParams("transaction_executed")
if state != nil {
if *state != "HALT" && *state != "FAULT" {
return "", errors.New("bad state parameter")
}
params.Values = append(params.Values, request.ExecutionFilter{State: *state})
}
return c.performSubscription(params)
}
// SubscribeForNotaryRequests adds subscription for notary request payloads
// addition or removal events to this instance of client. It can be filtered by
// request sender's hash, or main tx signer's hash, nil value puts no such
// restrictions.
func (c *WSClient) SubscribeForNotaryRequests(sender *util.Uint160, mainSigner *util.Uint160) (string, error) {
params := request.NewRawParams("notary_request_event")
if sender != nil {
params.Values = append(params.Values, request.TxFilter{Sender: sender, Signer: mainSigner})
}
return c.performSubscription(params)
}
// Unsubscribe removes subscription for given event stream.
func (c *WSClient) Unsubscribe(id string) error {
return c.performUnsubscription(id)
}
// UnsubscribeAll removes all active subscriptions of current client.
func (c *WSClient) UnsubscribeAll() error {
c.subscriptionsLock.Lock()
defer c.subscriptionsLock.Unlock()
for id := range c.subscriptions {
var resp bool
if err := c.performRequest("unsubscribe", request.NewRawParams(id), &resp); err != nil {
return err
}
if !resp {
return errors.New("unsubscribe method returned false result")
}
delete(c.subscriptions, id)
}
return nil
}