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package ws
import (
"io"
"sync"
"github.com/gorilla/websocket"
"github.com/canonical/lxd/shared/logger"
)
// NewWrapper returns a new ReadWriteCloser wrapper for a websocket connection.
func NewWrapper(conn *websocket.Conn) io.ReadWriteCloser {
return &wrapper{conn: conn}
}
// wrapper implements ReadWriteCloser on top of a websocket connection.
type wrapper struct {
conn *websocket.Conn
reader io.Reader
mur sync.Mutex
muw sync.Mutex
}
func (w *wrapper) Read(p []byte) (n int, err error) {
w.mur.Lock()
defer w.mur.Unlock()
// Get new message if no active one.
if w.reader == nil {
var mt int
mt, w.reader, err = w.conn.NextReader()
if err != nil {
if websocket.IsCloseError(err, websocket.CloseNormalClosure) {
logger.Debug("Websocket: Got normal closure", logger.Ctx{"address": w.conn.RemoteAddr().String()})
return 0, io.EOF
}
return 0, err
}
if mt == websocket.CloseMessage || mt == websocket.TextMessage {
switch mt {
case websocket.CloseMessage:
logger.Debug("Websocket: Got close message", logger.Ctx{"address": w.conn.RemoteAddr().String()})
case websocket.TextMessage:
logger.Debug("Websocket: Got barrier message", logger.Ctx{"address": w.conn.RemoteAddr().String()})
}
w.reader = nil // At the end of the message, reset reader.
return 0, io.EOF
}
}
// Perform the read itself.
n, err = w.reader.Read(p)
if err != nil {
w.reader = nil // At the end of the message, reset reader.
if err == io.EOF {
return n, nil // Don't return EOF error at end of message.
}
return n, err
}
return n, nil
}
func (w *wrapper) Write(p []byte) (int, error) {
w.muw.Lock()
defer w.muw.Unlock()
// Send the data as a binary message.
err := w.conn.WriteMessage(websocket.BinaryMessage, p)
if err != nil {
return 0, err
}
return len(p), nil
}
// Close sends a control message indicating the stream is finished, but it does not actually close the socket.
func (w *wrapper) Close() error {
w.muw.Lock()
defer w.muw.Unlock()
// Send the barrier message (don't actually close the socket so we can use it for another stream).
logger.Debug("Websocket: Sending barrier message", logger.Ctx{"address": w.conn.RemoteAddr().String()})
return w.conn.WriteMessage(websocket.TextMessage, []byte{})
}
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