status-go/vendor/nhooyr.io/websocket/ws_js.go

380 lines
8.7 KiB
Go

package websocket // import "nhooyr.io/websocket"
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"net/http"
"reflect"
"runtime"
"strings"
"sync"
"syscall/js"
"nhooyr.io/websocket/internal/bpool"
"nhooyr.io/websocket/internal/wsjs"
"nhooyr.io/websocket/internal/xsync"
)
// Conn provides a wrapper around the browser WebSocket API.
type Conn struct {
ws wsjs.WebSocket
// read limit for a message in bytes.
msgReadLimit xsync.Int64
closingMu sync.Mutex
isReadClosed xsync.Int64
closeOnce sync.Once
closed chan struct{}
closeErrOnce sync.Once
closeErr error
closeWasClean bool
releaseOnClose func()
releaseOnMessage func()
readSignal chan struct{}
readBufMu sync.Mutex
readBuf []wsjs.MessageEvent
}
func (c *Conn) close(err error, wasClean bool) {
c.closeOnce.Do(func() {
runtime.SetFinalizer(c, nil)
if !wasClean {
err = fmt.Errorf("unclean connection close: %w", err)
}
c.setCloseErr(err)
c.closeWasClean = wasClean
close(c.closed)
})
}
func (c *Conn) init() {
c.closed = make(chan struct{})
c.readSignal = make(chan struct{}, 1)
c.msgReadLimit.Store(32768)
c.releaseOnClose = c.ws.OnClose(func(e wsjs.CloseEvent) {
err := CloseError{
Code: StatusCode(e.Code),
Reason: e.Reason,
}
// We do not know if we sent or received this close as
// its possible the browser triggered it without us
// explicitly sending it.
c.close(err, e.WasClean)
c.releaseOnClose()
c.releaseOnMessage()
})
c.releaseOnMessage = c.ws.OnMessage(func(e wsjs.MessageEvent) {
c.readBufMu.Lock()
defer c.readBufMu.Unlock()
c.readBuf = append(c.readBuf, e)
// Lets the read goroutine know there is definitely something in readBuf.
select {
case c.readSignal <- struct{}{}:
default:
}
})
runtime.SetFinalizer(c, func(c *Conn) {
c.setCloseErr(errors.New("connection garbage collected"))
c.closeWithInternal()
})
}
func (c *Conn) closeWithInternal() {
c.Close(StatusInternalError, "something went wrong")
}
// Read attempts to read a message from the connection.
// The maximum time spent waiting is bounded by the context.
func (c *Conn) Read(ctx context.Context) (MessageType, []byte, error) {
if c.isReadClosed.Load() == 1 {
return 0, nil, errors.New("WebSocket connection read closed")
}
typ, p, err := c.read(ctx)
if err != nil {
return 0, nil, fmt.Errorf("failed to read: %w", err)
}
if int64(len(p)) > c.msgReadLimit.Load() {
err := fmt.Errorf("read limited at %v bytes", c.msgReadLimit.Load())
c.Close(StatusMessageTooBig, err.Error())
return 0, nil, err
}
return typ, p, nil
}
func (c *Conn) read(ctx context.Context) (MessageType, []byte, error) {
select {
case <-ctx.Done():
c.Close(StatusPolicyViolation, "read timed out")
return 0, nil, ctx.Err()
case <-c.readSignal:
case <-c.closed:
return 0, nil, c.closeErr
}
c.readBufMu.Lock()
defer c.readBufMu.Unlock()
me := c.readBuf[0]
// We copy the messages forward and decrease the size
// of the slice to avoid reallocating.
copy(c.readBuf, c.readBuf[1:])
c.readBuf = c.readBuf[:len(c.readBuf)-1]
if len(c.readBuf) > 0 {
// Next time we read, we'll grab the message.
select {
case c.readSignal <- struct{}{}:
default:
}
}
switch p := me.Data.(type) {
case string:
return MessageText, []byte(p), nil
case []byte:
return MessageBinary, p, nil
default:
panic("websocket: unexpected data type from wsjs OnMessage: " + reflect.TypeOf(me.Data).String())
}
}
// Ping is mocked out for Wasm.
func (c *Conn) Ping(ctx context.Context) error {
return nil
}
// Write writes a message of the given type to the connection.
// Always non blocking.
func (c *Conn) Write(ctx context.Context, typ MessageType, p []byte) error {
err := c.write(ctx, typ, p)
if err != nil {
// Have to ensure the WebSocket is closed after a write error
// to match the Go API. It can only error if the message type
// is unexpected or the passed bytes contain invalid UTF-8 for
// MessageText.
err := fmt.Errorf("failed to write: %w", err)
c.setCloseErr(err)
c.closeWithInternal()
return err
}
return nil
}
func (c *Conn) write(ctx context.Context, typ MessageType, p []byte) error {
if c.isClosed() {
return c.closeErr
}
switch typ {
case MessageBinary:
return c.ws.SendBytes(p)
case MessageText:
return c.ws.SendText(string(p))
default:
return fmt.Errorf("unexpected message type: %v", typ)
}
}
// Close closes the WebSocket with the given code and reason.
// It will wait until the peer responds with a close frame
// or the connection is closed.
// It thus performs the full WebSocket close handshake.
func (c *Conn) Close(code StatusCode, reason string) error {
err := c.exportedClose(code, reason)
if err != nil {
return fmt.Errorf("failed to close WebSocket: %w", err)
}
return nil
}
func (c *Conn) exportedClose(code StatusCode, reason string) error {
c.closingMu.Lock()
defer c.closingMu.Unlock()
ce := fmt.Errorf("sent close: %w", CloseError{
Code: code,
Reason: reason,
})
if c.isClosed() {
return fmt.Errorf("tried to close with %q but connection already closed: %w", ce, c.closeErr)
}
c.setCloseErr(ce)
err := c.ws.Close(int(code), reason)
if err != nil {
return err
}
<-c.closed
if !c.closeWasClean {
return c.closeErr
}
return nil
}
// Subprotocol returns the negotiated subprotocol.
// An empty string means the default protocol.
func (c *Conn) Subprotocol() string {
return c.ws.Subprotocol()
}
// DialOptions represents the options available to pass to Dial.
type DialOptions struct {
// Subprotocols lists the subprotocols to negotiate with the server.
Subprotocols []string
}
// Dial creates a new WebSocket connection to the given url with the given options.
// The passed context bounds the maximum time spent waiting for the connection to open.
// The returned *http.Response is always nil or a mock. It's only in the signature
// to match the core API.
func Dial(ctx context.Context, url string, opts *DialOptions) (*Conn, *http.Response, error) {
c, resp, err := dial(ctx, url, opts)
if err != nil {
return nil, nil, fmt.Errorf("failed to WebSocket dial %q: %w", url, err)
}
return c, resp, nil
}
func dial(ctx context.Context, url string, opts *DialOptions) (*Conn, *http.Response, error) {
if opts == nil {
opts = &DialOptions{}
}
url = strings.Replace(url, "http://", "ws://", 1)
url = strings.Replace(url, "https://", "wss://", 1)
ws, err := wsjs.New(url, opts.Subprotocols)
if err != nil {
return nil, nil, err
}
c := &Conn{
ws: ws,
}
c.init()
opench := make(chan struct{})
releaseOpen := ws.OnOpen(func(e js.Value) {
close(opench)
})
defer releaseOpen()
select {
case <-ctx.Done():
c.Close(StatusPolicyViolation, "dial timed out")
return nil, nil, ctx.Err()
case <-opench:
return c, &http.Response{
StatusCode: http.StatusSwitchingProtocols,
}, nil
case <-c.closed:
return nil, nil, c.closeErr
}
}
// Reader attempts to read a message from the connection.
// The maximum time spent waiting is bounded by the context.
func (c *Conn) Reader(ctx context.Context) (MessageType, io.Reader, error) {
typ, p, err := c.Read(ctx)
if err != nil {
return 0, nil, err
}
return typ, bytes.NewReader(p), nil
}
// Writer returns a writer to write a WebSocket data message to the connection.
// It buffers the entire message in memory and then sends it when the writer
// is closed.
func (c *Conn) Writer(ctx context.Context, typ MessageType) (io.WriteCloser, error) {
return writer{
c: c,
ctx: ctx,
typ: typ,
b: bpool.Get(),
}, nil
}
type writer struct {
closed bool
c *Conn
ctx context.Context
typ MessageType
b *bytes.Buffer
}
func (w writer) Write(p []byte) (int, error) {
if w.closed {
return 0, errors.New("cannot write to closed writer")
}
n, err := w.b.Write(p)
if err != nil {
return n, fmt.Errorf("failed to write message: %w", err)
}
return n, nil
}
func (w writer) Close() error {
if w.closed {
return errors.New("cannot close closed writer")
}
w.closed = true
defer bpool.Put(w.b)
err := w.c.Write(w.ctx, w.typ, w.b.Bytes())
if err != nil {
return fmt.Errorf("failed to close writer: %w", err)
}
return nil
}
// CloseRead implements *Conn.CloseRead for wasm.
func (c *Conn) CloseRead(ctx context.Context) context.Context {
c.isReadClosed.Store(1)
ctx, cancel := context.WithCancel(ctx)
go func() {
defer cancel()
c.read(ctx)
c.Close(StatusPolicyViolation, "unexpected data message")
}()
return ctx
}
// SetReadLimit implements *Conn.SetReadLimit for wasm.
func (c *Conn) SetReadLimit(n int64) {
c.msgReadLimit.Store(n)
}
func (c *Conn) setCloseErr(err error) {
c.closeErrOnce.Do(func() {
c.closeErr = fmt.Errorf("WebSocket closed: %w", err)
})
}
func (c *Conn) isClosed() bool {
select {
case <-c.closed:
return true
default:
return false
}
}