/
upgrader.go
243 lines (219 loc) · 7.53 KB
/
upgrader.go
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package websocket
import (
"bufio"
"bytes"
"fmt"
"github.com/aacfactory/errors"
"github.com/aacfactory/fns/commons/bytex"
"github.com/aacfactory/fns/context"
"github.com/aacfactory/fns/transports"
"net"
"net/http"
"net/url"
"sync"
"time"
)
const badHandshake = "websocket: the client is not using the websocket protocol: "
var strPermessageDeflate = []byte("permessage-deflate")
var poolWriteBuffer = sync.Pool{
New: func() interface{} {
var buf []byte
return buf
},
}
type HandshakeError struct {
message string
}
func (e HandshakeError) Error() string { return e.message }
type Handler func(ctx context.Context, conn *Conn, header transports.Header)
type Upgrader struct {
HandshakeTimeout time.Duration
ReadBufferSize int
WriteBufferSize int
WriteBufferPool BufferPool
Subprotocols []string
Error func(w transports.ResponseWriter, r transports.Request, status int, reason error)
CheckOrigin func(r transports.Request) bool
EnableCompression bool
}
func (u *Upgrader) responseError(w transports.ResponseWriter, r transports.Request, status int, reason string) error {
err := HandshakeError{reason}
if u.Error != nil {
u.Error(w, r, status, err)
} else {
w.Header().Set([]byte("Sec-Websocket-Version"), []byte("13"))
w.Header().Set(transports.ContentTypeHeaderName, []byte("text/plain; charset=utf-8"))
w.Header().Set([]byte("X-Content-Type-Options"), []byte("nosniff"))
w.SetStatus(status)
_, _ = w.Write(bytex.FromString(http.StatusText(status)))
}
return err
}
func (u *Upgrader) selectSubprotocol(w transports.ResponseWriter, r transports.Request) []byte {
if u.Subprotocols != nil {
clientProtocols := parseDataHeader(r.Header().Get([]byte("Sec-Websocket-Protocol")))
for _, serverProtocol := range u.Subprotocols {
for _, clientProtocol := range clientProtocols {
if bytex.ToString(clientProtocol) == serverProtocol {
return clientProtocol
}
}
}
} else if w.Header().Len() > 0 {
return w.Header().Get([]byte("Sec-Websocket-Protocol"))
}
return nil
}
func (u *Upgrader) isCompressionEnable(r transports.Request) bool {
extensions := parseDataHeader(r.Header().Get([]byte("Sec-WebSocket-Extensions")))
if u.EnableCompression {
for _, ext := range extensions {
if bytes.HasPrefix(ext, strPermessageDeflate) {
return true
}
}
}
return false
}
func (u *Upgrader) Upgrade(w transports.ResponseWriter, r transports.Request, handler Handler) error {
if !bytes.Equal(r.Method(), transports.MethodGet) {
return u.responseError(w, r, http.StatusMethodNotAllowed, fmt.Sprintf("%s request method is not GET", badHandshake))
}
if !tokenContainsValue(bytex.ToString(r.Header().Get(transports.ConnectionHeaderName)), "Upgrade") {
return u.responseError(w, r, http.StatusBadRequest, fmt.Sprintf("%s 'upgrade' token not found in 'Connection' header", badHandshake))
}
if !tokenContainsValue(bytex.ToString(r.Header().Get(transports.UpgradeHeaderName)), "Websocket") {
return u.responseError(w, r, http.StatusBadRequest, fmt.Sprintf("%s 'websocket' token not found in 'Upgrade' header", badHandshake))
}
if !tokenContainsValue(bytex.ToString(r.Header().Get([]byte("Sec-Websocket-Version"))), "13") {
return u.responseError(w, r, http.StatusBadRequest, "websocket: unsupported version: 13 not found in 'Sec-Websocket-Version' header")
}
if len(w.Header().Get([]byte("Sec-Websocket-Extensions"))) > 0 {
return u.responseError(w, r, http.StatusInternalServerError, "websocket: application specific 'Sec-WebSocket-Extensions' headers are unsupported")
}
checkOrigin := u.CheckOrigin
if checkOrigin == nil {
checkOrigin = checkSameOrigin
}
if !checkOrigin(r) {
return u.responseError(w, r, http.StatusForbidden, "websocket: request origin not allowed by FastHTTPUpgrader.CheckOrigin")
}
challengeKey := r.Header().Get([]byte("Sec-Websocket-Key"))
if len(challengeKey) == 0 {
return u.responseError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: `Sec-WebSocket-Key' header is missing or blank")
}
subprotocol := u.selectSubprotocol(w, r)
compress := u.isCompressionEnable(r)
async, hijackErr := w.Hijack(func(ctx context.Context, netConn net.Conn, rw *bufio.ReadWriter) (err error) {
var br *bufio.Reader
var writeBuf []byte
if rw != nil {
if rw.Reader.Buffered() > 0 {
_ = netConn.Close()
err = errors.Warning("websocket: client sent data before handshake is complete")
return
}
if u.ReadBufferSize == 0 && bufioReaderSize(netConn, rw.Reader) > 256 {
// Reuse hijacked buffered reader as connection reader.
br = rw.Reader
}
buf := bufioWriterBuffer(netConn, rw.Writer)
if u.WriteBufferPool == nil && u.WriteBufferSize == 0 && len(buf) >= maxFrameHeaderSize+256 {
// Reuse hijacked write buffer as connection buffer.
writeBuf = buf
}
} else {
writeBuf = poolWriteBuffer.Get().([]byte)
}
c := newConn(netConn, true, u.ReadBufferSize, u.WriteBufferSize, u.WriteBufferPool, br, writeBuf)
if subprotocol != nil {
c.subprotocol = bytex.ToString(subprotocol)
}
if compress {
c.newCompressionWriter = compressNoContextTakeover
c.newDecompressionReader = decompressNoContextTakeover
}
if rw != nil {
p := writeBuf
if len(c.writeBuf) > len(p) {
p = c.writeBuf
}
p = p[:0]
p = append(p, "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "...)
p = append(p, computeAcceptKey(bytex.ToString(challengeKey))...)
p = append(p, "\r\n"...)
if c.subprotocol != "" {
p = append(p, "Sec-WebSocket-Protocol: "...)
p = append(p, c.subprotocol...)
p = append(p, "\r\n"...)
}
if compress {
p = append(p, "Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover; client_no_context_takeover\r\n"...)
}
w.Header().Foreach(func(k []byte, values [][]byte) {
if bytes.Equal(k, []byte("Sec-Websocket-Protocol")) {
return
}
for _, v := range values {
p = append(p, k...)
p = append(p, ": "...)
for i := 0; i < len(v); i++ {
b := v[i]
if b <= 31 {
// prevent response splitting.
b = ' '
}
p = append(p, b)
}
p = append(p, "\r\n"...)
}
})
p = append(p, "\r\n"...)
if u.HandshakeTimeout > 0 {
_ = netConn.SetWriteDeadline(time.Now().Add(u.HandshakeTimeout))
}
if _, err = netConn.Write(p); err != nil {
_ = netConn.Close()
return
}
if u.HandshakeTimeout > 0 {
_ = netConn.SetWriteDeadline(time.Time{})
}
} else {
_ = netConn.SetDeadline(time.Time{})
}
handler(ctx, c, r.Header())
if rw == nil {
writeBuf = writeBuf[0:0]
poolWriteBuffer.Put(writeBuf)
}
return
})
if hijackErr != nil {
return errors.Warning("websocket: upgrade failed").WithCause(hijackErr)
}
if async {
w.SetStatus(http.StatusSwitchingProtocols)
w.Header().Set(transports.UpgradeHeaderName, []byte("websocket"))
w.Header().Set(transports.ConnectionHeaderName, []byte("Upgrade"))
w.Header().Set([]byte("Sec-WebSocket-Accept"), []byte(computeAcceptKeyBytes(challengeKey)))
if compress {
w.Header().Set([]byte("Sec-WebSocket-Extensions"), []byte("permessage-deflate; server_no_context_takeover; client_no_context_takeover"))
}
if subprotocol != nil {
w.Header().Set([]byte("Sec-WebSocket-Protocol"), subprotocol)
}
}
return nil
}
func checkSameOrigin(r transports.Request) bool {
origin := r.Header().Get(transports.OriginHeaderName)
if len(origin) == 0 {
return true
}
u, err := url.Parse(bytex.ToString(origin))
if err != nil {
return false
}
return equalASCIIFold(u.Host, bytex.ToString(r.Host()))
}