snapshot of https://github.com/gorilla/websocket.git (main, 2026-09-15; blobs > 131072B omitted)
This commit is contained in:
upstream-mirror
373
server.go
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373
server.go
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@@ -0,0 +1,373 @@
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// Copyright 2013 The Gorilla WebSocket Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package websocket
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import (
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"bufio"
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"net"
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"net/http"
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"net/url"
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"strings"
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"time"
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)
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// HandshakeError describes an error with the handshake from the peer.
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type HandshakeError struct {
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message string
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}
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func (e HandshakeError) Error() string { return e.message }
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// Upgrader specifies parameters for upgrading an HTTP connection to a
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// WebSocket connection.
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//
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// It is safe to call Upgrader's methods concurrently.
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type Upgrader struct {
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// HandshakeTimeout specifies the duration for the handshake to complete.
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HandshakeTimeout time.Duration
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// ReadBufferSize and WriteBufferSize specify I/O buffer sizes in bytes. If a buffer
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// size is zero, then buffers allocated by the HTTP server are used. The
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// I/O buffer sizes do not limit the size of the messages that can be sent
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// or received.
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ReadBufferSize, WriteBufferSize int
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// WriteBufferPool is a pool of buffers for write operations. If the value
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// is not set, then write buffers are allocated to the connection for the
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// lifetime of the connection.
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//
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// A pool is most useful when the application has a modest volume of writes
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// across a large number of connections.
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//
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// Applications should use a single pool for each unique value of
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// WriteBufferSize.
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WriteBufferPool BufferPool
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// Subprotocols specifies the server's supported protocols in order of
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// preference. If this field is not nil, then the Upgrade method negotiates a
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// subprotocol by selecting the first match in this list with a protocol
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// requested by the client. If there's no match, then no protocol is
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// negotiated (the Sec-Websocket-Protocol header is not included in the
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// handshake response).
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Subprotocols []string
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// Error specifies the function for generating HTTP error responses. If Error
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// is nil, then http.Error is used to generate the HTTP response.
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Error func(w http.ResponseWriter, r *http.Request, status int, reason error)
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// CheckOrigin returns true if the request Origin header is acceptable. If
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// CheckOrigin is nil, then a safe default is used: return false if the
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// Origin request header is present and the origin host is not equal to
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// request Host header.
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//
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// A CheckOrigin function should carefully validate the request origin to
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// prevent cross-site request forgery.
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CheckOrigin func(r *http.Request) bool
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// EnableCompression specify if the server should attempt to negotiate per
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// message compression (RFC 7692). Setting this value to true does not
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// guarantee that compression will be supported. Currently only "no context
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// takeover" modes are supported.
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EnableCompression bool
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}
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func (u *Upgrader) returnError(w http.ResponseWriter, r *http.Request, status int, reason string) (*Conn, error) {
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err := HandshakeError{reason}
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if u.Error != nil {
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u.Error(w, r, status, err)
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} else {
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w.Header().Set("Sec-Websocket-Version", "13")
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http.Error(w, http.StatusText(status), status)
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}
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return nil, err
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}
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// checkSameOrigin returns true if the origin is not set or is equal to the request host.
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func checkSameOrigin(r *http.Request) bool {
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origin := r.Header["Origin"]
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if len(origin) == 0 {
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return true
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}
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u, err := url.Parse(origin[0])
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if err != nil {
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return false
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}
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return equalASCIIFold(u.Host, r.Host)
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}
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func (u *Upgrader) selectSubprotocol(r *http.Request, responseHeader http.Header) string {
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if u.Subprotocols != nil {
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clientProtocols := Subprotocols(r)
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for _, clientProtocol := range clientProtocols {
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for _, serverProtocol := range u.Subprotocols {
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if clientProtocol == serverProtocol {
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return clientProtocol
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}
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}
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}
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} else if responseHeader != nil {
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return responseHeader.Get("Sec-Websocket-Protocol")
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}
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return ""
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}
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// Upgrade upgrades the HTTP server connection to the WebSocket protocol.
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//
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// The responseHeader is included in the response to the client's upgrade
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// request. Use the responseHeader to specify cookies (Set-Cookie). To specify
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// subprotocols supported by the server, set Upgrader.Subprotocols directly.
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//
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// If the upgrade fails, then Upgrade replies to the client with an HTTP error
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// response.
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func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header) (*Conn, error) {
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const badHandshake = "websocket: the client is not using the websocket protocol: "
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if !tokenListContainsValue(r.Header, "Connection", "upgrade") {
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return u.returnError(w, r, http.StatusBadRequest, badHandshake+"'upgrade' token not found in 'Connection' header")
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}
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if !tokenListContainsValue(r.Header, "Upgrade", "websocket") {
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w.Header().Set("Upgrade", "websocket")
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return u.returnError(w, r, http.StatusUpgradeRequired, badHandshake+"'websocket' token not found in 'Upgrade' header")
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}
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if r.Method != http.MethodGet {
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return u.returnError(w, r, http.StatusMethodNotAllowed, badHandshake+"request method is not GET")
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}
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if !tokenListContainsValue(r.Header, "Sec-Websocket-Version", "13") {
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return u.returnError(w, r, http.StatusBadRequest, "websocket: unsupported version: 13 not found in 'Sec-Websocket-Version' header")
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}
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if _, ok := responseHeader["Sec-Websocket-Extensions"]; ok {
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return u.returnError(w, r, http.StatusInternalServerError, "websocket: application specific 'Sec-WebSocket-Extensions' headers are unsupported")
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}
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checkOrigin := u.CheckOrigin
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if checkOrigin == nil {
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checkOrigin = checkSameOrigin
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}
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if !checkOrigin(r) {
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return u.returnError(w, r, http.StatusForbidden, "websocket: request origin not allowed by Upgrader.CheckOrigin")
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}
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challengeKey := r.Header.Get("Sec-Websocket-Key")
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if !isValidChallengeKey(challengeKey) {
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return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: 'Sec-WebSocket-Key' header must be Base64 encoded value of 16-byte in length")
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}
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subprotocol := u.selectSubprotocol(r, responseHeader)
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// Negotiate PMCE
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var compress bool
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if u.EnableCompression {
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for _, ext := range parseExtensions(r.Header) {
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if ext[""] != "permessage-deflate" {
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continue
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}
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compress = true
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break
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}
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}
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netConn, brw, err := http.NewResponseController(w).Hijack()
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if err != nil {
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return u.returnError(w, r, http.StatusInternalServerError,
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"websocket: hijack: "+err.Error())
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}
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// Close the network connection when returning an error. The variable
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// netConn is set to nil before the success return at the end of the
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// function.
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defer func() {
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if netConn != nil {
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// It's safe to ignore the error from Close() because this code is
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// only executed when returning a more important error to the
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// application.
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_ = netConn.Close()
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}
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}()
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var br *bufio.Reader
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if u.ReadBufferSize == 0 && brw.Reader.Size() > 256 {
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// Use hijacked buffered reader as the connection reader.
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br = brw.Reader
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} else if brw.Reader.Buffered() > 0 {
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// Wrap the network connection to read buffered data in brw.Reader
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// before reading from the network connection. This should be rare
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// because a client must not send message data before receiving the
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// handshake response.
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netConn = &brNetConn{br: brw.Reader, Conn: netConn}
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}
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buf := brw.Writer.AvailableBuffer()
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var writeBuf []byte
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if u.WriteBufferPool == nil && u.WriteBufferSize == 0 && len(buf) >= maxFrameHeaderSize+256 {
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// Reuse hijacked write buffer as connection buffer.
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writeBuf = buf
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}
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c := newConn(netConn, true, u.ReadBufferSize, u.WriteBufferSize, u.WriteBufferPool, br, writeBuf)
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c.subprotocol = subprotocol
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if compress {
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c.newCompressionWriter = compressNoContextTakeover
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c.newDecompressionReader = decompressNoContextTakeover
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}
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// Use larger of hijacked buffer and connection write buffer for header.
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p := buf
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if len(c.writeBuf) > len(p) {
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p = c.writeBuf
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}
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p = p[:0]
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p = append(p, "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: "...)
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p = append(p, computeAcceptKey(challengeKey)...)
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p = append(p, "\r\n"...)
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if c.subprotocol != "" {
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p = append(p, "Sec-WebSocket-Protocol: "...)
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p = append(p, c.subprotocol...)
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p = append(p, "\r\n"...)
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}
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if compress {
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p = append(p, "Sec-WebSocket-Extensions: permessage-deflate; server_no_context_takeover; client_no_context_takeover\r\n"...)
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}
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for k, vs := range responseHeader {
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if k == "Sec-Websocket-Protocol" {
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continue
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}
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for _, v := range vs {
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p = append(p, k...)
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p = append(p, ": "...)
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for i := 0; i < len(v); i++ {
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b := v[i]
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if b <= 31 {
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// prevent response splitting.
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b = ' '
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}
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p = append(p, b)
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}
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p = append(p, "\r\n"...)
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}
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}
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p = append(p, "\r\n"...)
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if u.HandshakeTimeout > 0 {
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if err := netConn.SetWriteDeadline(time.Now().Add(u.HandshakeTimeout)); err != nil {
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return nil, err
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}
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} else {
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// Clear deadlines set by HTTP server.
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if err := netConn.SetDeadline(time.Time{}); err != nil {
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return nil, err
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}
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}
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if _, err = netConn.Write(p); err != nil {
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return nil, err
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}
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if u.HandshakeTimeout > 0 {
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if err := netConn.SetWriteDeadline(time.Time{}); err != nil {
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return nil, err
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}
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}
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// Success! Set netConn to nil to stop the deferred function above from
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// closing the network connection.
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netConn = nil
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return c, nil
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}
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// Upgrade upgrades the HTTP server connection to the WebSocket protocol.
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//
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// Deprecated: Use websocket.Upgrader instead.
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//
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// Upgrade does not perform origin checking. The application is responsible for
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// checking the Origin header before calling Upgrade. An example implementation
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// of the same origin policy check is:
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//
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// if req.Header.Get("Origin") != "http://"+req.Host {
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// http.Error(w, "Origin not allowed", http.StatusForbidden)
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// return
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// }
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//
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// If the endpoint supports subprotocols, then the application is responsible
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// for negotiating the protocol used on the connection. Use the Subprotocols()
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// function to get the subprotocols requested by the client. Use the
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// Sec-Websocket-Protocol response header to specify the subprotocol selected
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// by the application.
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//
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// The responseHeader is included in the response to the client's upgrade
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// request. Use the responseHeader to specify cookies (Set-Cookie) and the
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// negotiated subprotocol (Sec-Websocket-Protocol).
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//
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// The connection buffers IO to the underlying network connection. The
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// readBufSize and writeBufSize parameters specify the size of the buffers to
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// use. Messages can be larger than the buffers.
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//
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// If the request is not a valid WebSocket handshake, then Upgrade returns an
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// error of type HandshakeError. Applications should handle this error by
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// replying to the client with an HTTP error response.
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func Upgrade(w http.ResponseWriter, r *http.Request, responseHeader http.Header, readBufSize, writeBufSize int) (*Conn, error) {
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u := Upgrader{ReadBufferSize: readBufSize, WriteBufferSize: writeBufSize}
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u.Error = func(w http.ResponseWriter, r *http.Request, status int, reason error) {
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// don't return errors to maintain backwards compatibility
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}
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u.CheckOrigin = func(r *http.Request) bool {
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// allow all connections by default
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return true
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}
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return u.Upgrade(w, r, responseHeader)
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}
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// Subprotocols returns the subprotocols requested by the client in the
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// Sec-Websocket-Protocol header.
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func Subprotocols(r *http.Request) []string {
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h := strings.TrimSpace(r.Header.Get("Sec-Websocket-Protocol"))
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if h == "" {
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return nil
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}
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protocols := strings.Split(h, ",")
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for i := range protocols {
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protocols[i] = strings.TrimSpace(protocols[i])
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}
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return protocols
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}
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// IsWebSocketUpgrade returns true if the client requested upgrade to the
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// WebSocket protocol.
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func IsWebSocketUpgrade(r *http.Request) bool {
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return tokenListContainsValue(r.Header, "Connection", "upgrade") &&
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tokenListContainsValue(r.Header, "Upgrade", "websocket")
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}
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type brNetConn struct {
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br *bufio.Reader
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net.Conn
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}
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func (b *brNetConn) Read(p []byte) (n int, err error) {
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if b.br != nil {
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// Limit read to buferred data.
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if n := b.br.Buffered(); len(p) > n {
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p = p[:n]
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}
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n, err = b.br.Read(p)
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if b.br.Buffered() == 0 {
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b.br = nil
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}
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return n, err
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}
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return b.Conn.Read(p)
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}
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// NetConn returns the underlying connection that is wrapped by b.
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func (b *brNetConn) NetConn() net.Conn {
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return b.Conn
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}
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Reference in New Issue
Block a user