/
conn.go
193 lines (167 loc) · 4.08 KB
/
conn.go
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package signalflow
import (
"context"
"fmt"
"net/url"
"path"
"time"
"github.com/gorilla/websocket"
)
// How long to wait between connections in case of a bad connection.
var reconnectDelay = 5 * time.Second
type wsConn struct {
StreamURL *url.URL
OutgoingTextMsgs chan *outgoingMessage
IncomingTextMsgs chan []byte
IncomingBinaryMsgs chan []byte
ConnectedCh chan struct{}
ConnectTimeout time.Duration
ReadTimeout time.Duration
WriteTimeout time.Duration
OnError OnErrorFunc
PostDisconnectCallback func()
PostConnectMessage func() []byte
}
type outgoingMessage struct {
bytes []byte
resultCh chan error
}
// Run keeps the connection alive and puts all incoming messages into a channel
// as needed.
func (c *wsConn) Run(ctx context.Context) {
var conn *websocket.Conn
defer func() {
if conn != nil {
conn.Close()
}
}()
for {
if conn != nil {
conn.Close()
time.Sleep(reconnectDelay)
}
// This will get run on before the first connection as well.
if c.PostDisconnectCallback != nil {
c.PostDisconnectCallback()
}
if ctx.Err() != nil {
return
}
dialCtx, cancel := context.WithTimeout(ctx, c.ConnectTimeout)
var err error
conn, err = c.connect(dialCtx)
cancel()
if err != nil {
c.sendErrIfWanted(fmt.Errorf("Error connecting to SignalFlow websocket: %w", err))
continue
}
err = c.postConnect(conn)
if err != nil {
c.sendErrIfWanted(fmt.Errorf("Error setting up SignalFlow websocket: %w", err))
continue
}
err = c.readAndWriteMessages(conn)
if err == nil {
return
}
c.sendErrIfWanted(fmt.Errorf("Error in SignalFlow websocket: %w", err))
}
}
type messageWithType struct {
bytes []byte
msgType int
}
func (c *wsConn) readAndWriteMessages(conn *websocket.Conn) error {
readMessageCh := make(chan messageWithType)
readErrCh := make(chan error)
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
go func() {
for {
bytes, typ, err := readNextMessage(conn, c.ReadTimeout)
if err != nil {
select {
case readErrCh <- err:
case <-ctx.Done():
}
return
}
readMessageCh <- messageWithType{
bytes: bytes,
msgType: typ,
}
}
}()
for {
select {
case msg, ok := <-readMessageCh:
if !ok {
return nil
}
if msg.msgType == websocket.TextMessage {
c.IncomingTextMsgs <- msg.bytes
} else {
c.IncomingBinaryMsgs <- msg.bytes
}
case err := <-readErrCh:
return err
case msg, ok := <-c.OutgoingTextMsgs:
if !ok {
return nil
}
err := c.writeMessage(conn, msg.bytes)
msg.resultCh <- err
if err != nil {
return err
}
}
}
}
func (c *wsConn) sendErrIfWanted(err error) {
if c.OnError != nil {
c.OnError(err)
}
}
func (c *wsConn) Close() {
close(c.IncomingTextMsgs)
close(c.IncomingBinaryMsgs)
}
func (c *wsConn) connect(ctx context.Context) (*websocket.Conn, error) {
connectURL := *c.StreamURL
connectURL.Path = path.Join(c.StreamURL.Path, "connect")
conn, _, err := websocket.DefaultDialer.DialContext(ctx, connectURL.String(), nil)
if err != nil {
return nil, fmt.Errorf("could not connect Signalflow websocket: %w", err)
}
return conn, nil
}
func (c *wsConn) postConnect(conn *websocket.Conn) error {
if c.PostConnectMessage != nil {
msg := c.PostConnectMessage()
if msg != nil {
return c.writeMessage(conn, msg)
}
}
return nil
}
func readNextMessage(conn *websocket.Conn, timeout time.Duration) (data []byte, msgType int, err error) {
if err := conn.SetReadDeadline(time.Now().Add(timeout)); err != nil {
return nil, 0, fmt.Errorf("could not set read timeout in SignalFlow client: %w", err)
}
typ, bytes, err := conn.ReadMessage()
if err != nil {
return nil, 0, err
}
return bytes, typ, nil
}
func (c *wsConn) writeMessage(conn *websocket.Conn, msgBytes []byte) error {
err := conn.SetWriteDeadline(time.Now().Add(c.WriteTimeout))
if err != nil {
return fmt.Errorf("could not set write timeout for SignalFlow request: %w", err)
}
err = conn.WriteMessage(websocket.TextMessage, msgBytes)
if err != nil {
return err
}
return nil
}