move sockjs to Centrifugo to start deprecation process

Author: FZambia

go.mod

@@ -70,7 +70,7 @@ require (
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/google/pprof v0.0.0-20230926050212-f7f687d19a98 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.16.0 // indirect
-	github.com/igm/sockjs-go/v3 v3.0.2 // indirect
+	github.com/igm/sockjs-go/v3 v3.0.2
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/klauspost/compress v1.17.2 // indirect

internal/sockjs/cancelctx.go

@@ -0,0 +1,34 @@
+package sockjs
+
+import (
+	"context"
+	"time"
+)
+
+// customCancelContext wraps context and cancels as soon as channel closed.
+type customCancelContext struct {
+	context.Context
+	ch <-chan struct{}
+}
+
+// Deadline not used.
+func (c customCancelContext) Deadline() (time.Time, bool) { return time.Time{}, false }
+
+// Done returns channel that will be closed as soon as connection closed.
+func (c customCancelContext) Done() <-chan struct{} { return c.ch }
+
+// Err returns context error.
+func (c customCancelContext) Err() error {
+	select {
+	case <-c.ch:
+		return context.Canceled
+	default:
+		return nil
+	}
+}
+
+// NewCancelContext returns a wrapper context around original context that will
+// be canceled on channel close.
+func NewCancelContext(ctx context.Context, ch <-chan struct{}) context.Context {
+	return customCancelContext{Context: ctx, ch: ch}
+}

internal/sockjs/handler_sockjs.go

@@ -0,0 +1,278 @@
+package sockjs
+
+import (
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/centrifugal/centrifuge"
+
+	"github.com/centrifugal/protocol"
+	"github.com/gorilla/websocket"
+	"github.com/igm/sockjs-go/v3/sockjs"
+)
+
+// Config represents config for SockJS handler.
+type Config struct {
+	// HandlerPrefix sets prefix for SockJS handler endpoint path.
+	HandlerPrefix string
+
+	// URL is an address to SockJS client javascript library. Required for iframe-based
+	// transports to work. This URL should lead to the same SockJS client version as used
+	// for connecting on the client side.
+	URL string
+
+	// CheckOrigin allows deciding whether to use CORS or not in XHR case.
+	// When false returned then CORS headers won't be set.
+	CheckOrigin func(*http.Request) bool
+
+	// WebsocketCheckOrigin allows setting custom CheckOrigin func for underlying
+	// Gorilla Websocket based websocket.Upgrader.
+	WebsocketCheckOrigin func(*http.Request) bool
+
+	// WebsocketReadBufferSize is a parameter that is used for raw websocket.Upgrader.
+	// If set to zero reasonable default value will be used.
+	WebsocketReadBufferSize int
+
+	// WebsocketWriteBufferSize is a parameter that is used for raw websocket.Upgrader.
+	// If set to zero reasonable default value will be used.
+	WebsocketWriteBufferSize int
+
+	// WebsocketUseWriteBufferPool enables using buffer pool for writes in Websocket transport.
+	WebsocketUseWriteBufferPool bool
+
+	// WebsocketWriteTimeout is maximum time of write message operation.
+	// Slow client will be disconnected.
+	// By default, 1 * time.Second will be used.
+	WebsocketWriteTimeout time.Duration
+
+	centrifuge.PingPongConfig
+}
+
+// Handler accepts SockJS connections. SockJS has a bunch of fallback
+// transports when WebSocket connection is not supported. It comes with additional
+// costs though: small protocol framing overhead, lack of binary support, more
+// goroutines per connection, and you need to use sticky session mechanism on
+// your load balancer in case you are using HTTP-based SockJS fallbacks and have
+// more than one Centrifuge Node on a backend (so SockJS to be able to emulate
+// bidirectional protocol). So if you can afford it - use WebsocketHandler only.
+type Handler struct {
+	node    *centrifuge.Node
+	config  Config
+	handler http.Handler
+}
+
+var writeBufferPool = &sync.Pool{}
+
+// NewHandler creates new Handler.
+func NewHandler(node *centrifuge.Node, config Config) *Handler {
+	options := sockjs.DefaultOptions
+
+	wsUpgrader := &websocket.Upgrader{
+		ReadBufferSize:  config.WebsocketReadBufferSize,
+		WriteBufferSize: config.WebsocketWriteBufferSize,
+		Error:           func(w http.ResponseWriter, r *http.Request, status int, reason error) {},
+	}
+	wsUpgrader.CheckOrigin = config.WebsocketCheckOrigin
+	if config.WebsocketUseWriteBufferPool {
+		wsUpgrader.WriteBufferPool = writeBufferPool
+	} else {
+		wsUpgrader.WriteBufferSize = config.WebsocketWriteBufferSize
+	}
+	options.WebsocketUpgrader = wsUpgrader
+
+	// Override sockjs url. It's important to use the same SockJS
+	// library version on client and server sides when using iframe
+	// based SockJS transports, otherwise SockJS will raise error
+	// about version mismatch.
+	options.SockJSURL = config.URL
+	options.CheckOrigin = config.CheckOrigin
+
+	wsWriteTimeout := config.WebsocketWriteTimeout
+	if wsWriteTimeout == 0 {
+		wsWriteTimeout = 1 * time.Second
+	}
+	options.WebsocketWriteTimeout = wsWriteTimeout
+
+	s := &Handler{
+		node:   node,
+		config: config,
+	}
+
+	options.HeartbeatDelay = 0
+	s.handler = sockjs.NewHandler(config.HandlerPrefix, options, s.sockJSHandler)
+	return s
+}
+
+func (s *Handler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
+	s.handler.ServeHTTP(rw, r)
+}
+
+// sockJSHandler called when new client connection comes to SockJS endpoint.
+func (s *Handler) sockJSHandler(sess sockjs.Session) {
+	s.handleSession(sess)
+}
+
+// sockJSHandler called when new client connection comes to SockJS endpoint.
+func (s *Handler) handleSession(sess sockjs.Session) {
+	// Separate goroutine for better GC of caller's data.
+	go func() {
+		transport := newSockjsTransport(sess, sockjsTransportOptions{
+			pingPong: s.config.PingPongConfig,
+		})
+
+		select {
+		case <-s.node.NotifyShutdown():
+			_ = transport.Close(centrifuge.DisconnectShutdown)
+			return
+		default:
+		}
+
+		ctxCh := make(chan struct{})
+		defer close(ctxCh)
+		c, closeFn, err := centrifuge.NewClient(NewCancelContext(sess.Request().Context(), ctxCh), s.node, transport)
+		if err != nil {
+			s.node.Log(centrifuge.NewLogEntry(centrifuge.LogLevelError, "error creating client", map[string]any{"transport": transportSockJS}))
+			return
+		}
+		defer func() { _ = closeFn() }()
+
+		if s.node.LogEnabled(centrifuge.LogLevelDebug) {
+			s.node.Log(centrifuge.NewLogEntry(centrifuge.LogLevelDebug, "client connection established", map[string]any{"client": c.ID(), "transport": transportSockJS}))
+			defer func(started time.Time) {
+				s.node.Log(centrifuge.NewLogEntry(centrifuge.LogLevelDebug, "client connection completed", map[string]any{"client": c.ID(), "transport": transportSockJS, "duration": time.Since(started)}))
+			}(time.Now())
+		}
+
+		var needWaitLoop bool
+
+		for {
+			if msg, err := sess.Recv(); err == nil {
+				reader := GetStringReader(msg)
+				if ok := centrifuge.HandleReadFrame(c, reader); !ok {
+					PutStringReader(reader)
+					needWaitLoop = true
+					break
+				}
+				PutStringReader(reader)
+				continue
+			}
+			break
+		}
+
+		if needWaitLoop {
+			// One extra loop till we get an error from session,
+			// this is required to wait until close frame will be sent
+			// into connection inside Client implementation and transport
+			// closed with proper disconnect reason.
+			for {
+				if _, err := sess.Recv(); err != nil {
+					break
+				}
+			}
+		}
+	}()
+}
+
+const (
+	transportSockJS = "sockjs"
+)
+
+type sockjsTransportOptions struct {
+	pingPong centrifuge.PingPongConfig
+}
+
+type sockjsTransport struct {
+	mu      sync.RWMutex
+	closeCh chan struct{}
+	session sockjs.Session
+	opts    sockjsTransportOptions
+	closed  bool
+}
+
+func newSockjsTransport(s sockjs.Session, opts sockjsTransportOptions) *sockjsTransport {
+	t := &sockjsTransport{
+		session: s,
+		closeCh: make(chan struct{}),
+		opts:    opts,
+	}
+	return t
+}
+
+// Name returns name of transport.
+func (t *sockjsTransport) Name() string {
+	return transportSockJS
+}
+
+// Protocol returns transport protocol.
+func (t *sockjsTransport) Protocol() centrifuge.ProtocolType {
+	return centrifuge.ProtocolTypeJSON
+}
+
+// ProtocolVersion returns transport ProtocolVersion.
+func (t *sockjsTransport) ProtocolVersion() centrifuge.ProtocolVersion {
+	return centrifuge.ProtocolVersion2
+}
+
+// Unidirectional returns whether transport is unidirectional.
+func (t *sockjsTransport) Unidirectional() bool {
+	return false
+}
+
+// Emulation ...
+func (t *sockjsTransport) Emulation() bool {
+	return false
+}
+
+// DisabledPushFlags ...
+func (t *sockjsTransport) DisabledPushFlags() uint64 {
+	// SockJS has its own close frames to mimic WebSocket Close frames,
+	// so we don't need to send Disconnect pushes.
+	return centrifuge.PushFlagDisconnect
+}
+
+// PingPongConfig ...
+func (t *sockjsTransport) PingPongConfig() centrifuge.PingPongConfig {
+	return t.opts.pingPong
+}
+
+// Write data to transport.
+func (t *sockjsTransport) Write(message []byte) error {
+	select {
+	case <-t.closeCh:
+		return nil
+	default:
+		// No need to use protocol encoders here since
+		// SockJS only supports JSON.
+		return t.session.Send(string(message))
+	}
+}
+
+// WriteMany messages to transport.
+func (t *sockjsTransport) WriteMany(messages ...[]byte) error {
+	select {
+	case <-t.closeCh:
+		return nil
+	default:
+		encoder := protocol.GetDataEncoder(protocol.Type(centrifuge.ProtocolTypeJSON))
+		defer protocol.PutDataEncoder(protocol.Type(centrifuge.ProtocolTypeJSON), encoder)
+		for i := range messages {
+			_ = encoder.Encode(messages[i])
+		}
+		return t.session.Send(string(encoder.Finish()))
+	}
+}
+
+// Close closes transport.
+func (t *sockjsTransport) Close(disconnect centrifuge.Disconnect) error {
+	t.mu.Lock()
+	if t.closed {
+		// Already closed, noop.
+		t.mu.Unlock()
+		return nil
+	}
+	t.closed = true
+	close(t.closeCh)
+	t.mu.Unlock()
+	return t.session.Close(disconnect.Code, disconnect.Reason)
+}