/
proxy.go
725 lines (650 loc) · 24.9 KB
/
proxy.go
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package workspaceapps
import (
"context"
"fmt"
"net"
"net/http"
"net/http/httputil"
"net/url"
"regexp"
"strconv"
"strings"
"sync"
"github.com/go-chi/chi/v5"
"github.com/google/uuid"
"go.opentelemetry.io/otel/trace"
"nhooyr.io/websocket"
"cdr.dev/slog"
"github.com/coder/coder/agent/agentssh"
"github.com/coder/coder/coderd/httpapi"
"github.com/coder/coder/coderd/httpmw"
"github.com/coder/coder/coderd/tracing"
"github.com/coder/coder/coderd/util/slice"
"github.com/coder/coder/codersdk"
"github.com/coder/coder/site"
)
const (
// This needs to be a super unique query parameter because we don't want to
// conflict with query parameters that users may use.
//nolint:gosec
SubdomainProxyAPIKeyParam = "coder_application_connect_api_key_35e783"
// appLogoutHostname is the hostname to use for the logout redirect. When
// the dashboard logs out, it will redirect to this subdomain of the app
// hostname, and the server will remove the cookie and redirect to the main
// login page.
// It is important that this URL can never match a valid app hostname.
//
// DEPRECATED: we no longer use this, but we still redirect from it to the
// main login page.
appLogoutHostname = "coder-logout"
)
// nonCanonicalHeaders is a map from "canonical" headers to the actual header we
// should send to the app in the workspace. Some headers (such as the websocket
// upgrade headers from RFC 6455) are not canonical according to the HTTP/1
// spec. Golang has said that they will not add custom cases for these headers,
// so we need to do it ourselves.
//
// Some apps our customers use are sensitive to the case of these headers.
//
// https://github.com/golang/go/issues/18495
var nonCanonicalHeaders = map[string]string{
"Sec-Websocket-Accept": "Sec-WebSocket-Accept",
"Sec-Websocket-Extensions": "Sec-WebSocket-Extensions",
"Sec-Websocket-Key": "Sec-WebSocket-Key",
"Sec-Websocket-Protocol": "Sec-WebSocket-Protocol",
"Sec-Websocket-Version": "Sec-WebSocket-Version",
}
type AgentProvider interface {
// ReverseProxy returns an httputil.ReverseProxy for proxying HTTP requests
// to the specified agent.
//
// TODO: after wsconncache is deleted this doesn't need to return an error.
ReverseProxy(targetURL, dashboardURL *url.URL, agentID uuid.UUID) (_ *httputil.ReverseProxy, release func(), _ error)
// AgentConn returns a new connection to the specified agent.
//
// TODO: after wsconncache is deleted this doesn't need to return a release
// func.
AgentConn(ctx context.Context, agentID uuid.UUID) (_ *codersdk.WorkspaceAgentConn, release func(), _ error)
Close() error
}
// Server serves workspace apps endpoints, including:
// - Path-based apps
// - Subdomain app middleware
// - Workspace reconnecting-pty (aka. web terminal)
type Server struct {
Logger slog.Logger
// DashboardURL should be a url to the coderd dashboard. This can be the
// same as the AccessURL if the Server is embedded.
DashboardURL *url.URL
AccessURL *url.URL
// Hostname should be the wildcard hostname to use for workspace
// applications INCLUDING the asterisk, (optional) suffix and leading dot.
// It will use the same scheme and port number as the access URL.
// E.g. "*.apps.coder.com" or "*-apps.coder.com".
Hostname string
// HostnameRegex contains the regex version of Hostname as generated by
// httpapi.CompileHostnamePattern(). It MUST be set if Hostname is set.
HostnameRegex *regexp.Regexp
RealIPConfig *httpmw.RealIPConfig
SignedTokenProvider SignedTokenProvider
AppSecurityKey SecurityKey
// DisablePathApps disables path-based apps. This is a security feature as path
// based apps share the same cookie as the dashboard, and are susceptible to XSS
// by a malicious workspace app.
//
// Subdomain apps are safer with their cookies scoped to the subdomain, and XSS
// calls to the dashboard are not possible due to CORs.
DisablePathApps bool
SecureAuthCookie bool
AgentProvider AgentProvider
websocketWaitMutex sync.Mutex
websocketWaitGroup sync.WaitGroup
}
// Close waits for all reconnecting-pty WebSocket connections to drain before
// returning.
func (s *Server) Close() error {
s.websocketWaitMutex.Lock()
s.websocketWaitGroup.Wait()
s.websocketWaitMutex.Unlock()
// The caller must close the SignedTokenProvider and the AgentProvider (if
// necessary).
return nil
}
func (s *Server) Attach(r chi.Router) {
servePathApps := func(r chi.Router) {
r.HandleFunc("/*", s.workspaceAppsProxyPath)
}
// %40 is the encoded character of the @ symbol. VS Code Web does
// not handle character encoding properly, so it's safe to assume
// other applications might not as well.
r.Route("/%40{user}/{workspace_and_agent}/apps/{workspaceapp}", servePathApps)
r.Route("/@{user}/{workspace_and_agent}/apps/{workspaceapp}", servePathApps)
r.Get("/api/v2/workspaceagents/{workspaceagent}/pty", s.workspaceAgentPTY)
}
// handleAPIKeySmuggling is called by the proxy path and subdomain handlers to
// process any "smuggled" API keys in the query parameters.
//
// If a smuggled key is found, it is decrypted and the cookie is set, and the
// user is redirected to strip the query parameter.
func (s *Server) handleAPIKeySmuggling(rw http.ResponseWriter, r *http.Request, accessMethod AccessMethod) bool {
ctx := r.Context()
encryptedAPIKey := r.URL.Query().Get(SubdomainProxyAPIKeyParam)
if encryptedAPIKey == "" {
return true
}
// API key smuggling is not permitted for path apps on the primary access
// URL. The user is already covered by their full session token.
if accessMethod == AccessMethodPath && s.AccessURL.Host == s.DashboardURL.Host {
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusBadRequest,
Title: "Bad Request",
Description: "Could not decrypt API key. Workspace app API key smuggling is not permitted on the primary access URL. Please remove the query parameter and try again.",
// Retry is disabled because the user needs to remove the query
// parameter before they try again.
RetryEnabled: false,
DashboardURL: s.DashboardURL.String(),
})
return false
}
// Exchange the encoded API key for a real one.
token, err := s.AppSecurityKey.DecryptAPIKey(encryptedAPIKey)
if err != nil {
s.Logger.Debug(ctx, "could not decrypt smuggled workspace app API key", slog.Error(err))
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusBadRequest,
Title: "Bad Request",
Description: "Could not decrypt API key. Please remove the query parameter and try again.",
// Retry is disabled because the user needs to remove the query
// parameter before they try again.
RetryEnabled: false,
DashboardURL: s.DashboardURL.String(),
})
return false
}
// Set the cookie. For subdomain apps, we set the cookie on the whole
// wildcard so users don't need to re-auth for every subdomain app they
// access. For path apps (only on proxies, see above) we just set it on the
// current domain.
domain := "" // use the current domain
if accessMethod == AccessMethodSubdomain {
hostSplit := strings.SplitN(s.Hostname, ".", 2)
if len(hostSplit) != 2 {
// This should be impossible as we verify the app hostname on
// startup, but we'll check anyways.
s.Logger.Error(r.Context(), "could not split invalid app hostname", slog.F("hostname", s.Hostname))
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusInternalServerError,
Title: "Internal Server Error",
Description: "The app is configured with an invalid app wildcard hostname. Please contact an administrator.",
RetryEnabled: false,
DashboardURL: s.DashboardURL.String(),
})
return false
}
// Set the cookie for all subdomains of s.Hostname.
domain = "." + hostSplit[1]
}
// We don't set an expiration because the key in the database already has an
// expiration, and expired tokens don't affect the user experience (they get
// auto-redirected to re-smuggle the API key).
http.SetCookie(rw, &http.Cookie{
Name: codersdk.DevURLSessionTokenCookie,
Value: token,
Domain: domain,
Path: "/",
MaxAge: 0,
HttpOnly: true,
SameSite: http.SameSiteLaxMode,
Secure: s.SecureAuthCookie,
})
// Strip the query parameter.
path := r.URL.Path
if path == "" {
path = "/"
}
q := r.URL.Query()
q.Del(SubdomainProxyAPIKeyParam)
rawQuery := q.Encode()
if rawQuery != "" {
path += "?" + q.Encode()
}
http.Redirect(rw, r, path, http.StatusSeeOther)
return false
}
// workspaceAppsProxyPath proxies requests to a workspace application
// through a relative URL path.
func (s *Server) workspaceAppsProxyPath(rw http.ResponseWriter, r *http.Request) {
if s.DisablePathApps {
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusUnauthorized,
Title: "Unauthorized",
Description: "Path-based applications are disabled on this Coder deployment by the administrator.",
RetryEnabled: false,
DashboardURL: s.DashboardURL.String(),
})
return
}
// We don't support @me in path apps since it requires the database to
// lookup the username from token. We used to redirect by doing this lookup.
if chi.URLParam(r, "user") == codersdk.Me {
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusNotFound,
Title: "Application Not Found",
Description: "Applications must be accessed with the full username, not @me.",
RetryEnabled: false,
DashboardURL: s.DashboardURL.String(),
})
return
}
if !s.handleAPIKeySmuggling(rw, r, AccessMethodPath) {
return
}
// Determine the real path that was hit. The * URL parameter in Chi will not
// include the leading slash if it was present, so we need to add it back.
chiPath := chi.URLParam(r, "*")
basePath := strings.TrimSuffix(r.URL.Path, chiPath)
if strings.HasSuffix(basePath, "/") {
chiPath = "/" + chiPath
}
// ResolveRequest will only return a new signed token if the actor has the RBAC
// permissions to connect to a workspace.
token, ok := ResolveRequest(rw, r, ResolveRequestOptions{
Logger: s.Logger,
SignedTokenProvider: s.SignedTokenProvider,
DashboardURL: s.DashboardURL,
PathAppBaseURL: s.AccessURL,
AppHostname: s.Hostname,
AppRequest: Request{
AccessMethod: AccessMethodPath,
BasePath: basePath,
UsernameOrID: chi.URLParam(r, "user"),
WorkspaceAndAgent: chi.URLParam(r, "workspace_and_agent"),
// We don't support port proxying on paths. The ResolveRequest method
// won't allow port proxying on path-based apps if the app is a number.
AppSlugOrPort: chi.URLParam(r, "workspaceapp"),
},
AppPath: chiPath,
AppQuery: r.URL.RawQuery,
})
if !ok {
return
}
s.proxyWorkspaceApp(rw, r, *token, chiPath)
}
// HandleSubdomain handles subdomain-based application proxy requests (aka.
// DevURLs in Coder V1).
//
// There are a lot of paths here:
// 1. If api.Hostname is not set then we pass on.
// 2. If we can't read the request hostname then we return a 400.
// 3. If the request hostname matches api.AccessURL then we pass on.
// 5. We split the subdomain into the subdomain and the "rest". If there are no
// periods in the hostname then we pass on.
// 5. We parse the subdomain into a httpapi.ApplicationURL struct. If we
// encounter an error:
// a. If the "rest" does not match api.Hostname then we pass on;
// b. Otherwise, we return a 400.
// 6. Finally, we verify that the "rest" matches api.Hostname, else we
// return a 404.
//
// Rationales for each of the above steps:
// 1. We pass on if api.Hostname is not set to avoid returning any errors if
// `--app-hostname` is not configured.
// 2. Every request should have a valid Host header anyways.
// 3. We pass on if the request hostname matches api.AccessURL so we can
// support having the access URL be at the same level as the application
// base hostname.
// 4. We pass on if there are no periods in the hostname as application URLs
// must be a subdomain of a hostname, which implies there must be at least
// one period.
// 5. a. If the request subdomain is not a valid application URL, and the
// "rest" does not match api.Hostname, then it is very unlikely that
// the request was intended for this handler. We pass on.
// b. If the request subdomain is not a valid application URL, but the
// "rest" matches api.Hostname, then we return a 400 because the
// request is probably a typo or something.
// 6. We finally verify that the "rest" matches api.Hostname for security
// purposes regarding re-authentication and application proxy session
// tokens.
func (s *Server) HandleSubdomain(middlewares ...func(http.Handler) http.Handler) func(http.Handler) http.Handler {
return func(next http.Handler) http.Handler {
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
ctx := r.Context()
// Step 1: Pass on if subdomain-based application proxying is not
// configured.
if s.Hostname == "" || s.HostnameRegex == nil {
next.ServeHTTP(rw, r)
return
}
// Step 2: Get the request Host.
host := httpapi.RequestHost(r)
if host == "" {
if r.URL.Path == "/derp" {
// The /derp endpoint is used by wireguard clients to tunnel
// through coderd. For some reason these requests don't set
// a Host header properly sometimes in tests (no idea how),
// which causes this path to get hit.
next.ServeHTTP(rw, r)
return
}
httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
Message: "Could not determine request Host.",
})
return
}
// Steps 3-6: Parse application from subdomain.
app, ok := s.parseHostname(rw, r, next, host)
if !ok {
return
}
// Use the passed in app middlewares before checking authentication and
// passing to the proxy app.
mws := chi.Middlewares(append(middlewares, httpmw.WorkspaceAppCors(s.HostnameRegex, app)))
mws.Handler(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
if !s.handleAPIKeySmuggling(rw, r, AccessMethodSubdomain) {
return
}
token, ok := ResolveRequest(rw, r, ResolveRequestOptions{
Logger: s.Logger,
SignedTokenProvider: s.SignedTokenProvider,
DashboardURL: s.DashboardURL,
PathAppBaseURL: s.AccessURL,
AppHostname: s.Hostname,
AppRequest: Request{
AccessMethod: AccessMethodSubdomain,
BasePath: "/",
UsernameOrID: app.Username,
WorkspaceNameOrID: app.WorkspaceName,
AgentNameOrID: app.AgentName,
AppSlugOrPort: app.AppSlugOrPort,
},
AppPath: r.URL.Path,
AppQuery: r.URL.RawQuery,
})
if !ok {
return
}
s.proxyWorkspaceApp(rw, r, *token, r.URL.Path)
})).ServeHTTP(rw, r.WithContext(ctx))
})
}
}
// parseHostname will return if a given request is attempting to access a
// workspace app via a subdomain. If it is, the hostname of the request is parsed
// into an httpapi.ApplicationURL and true is returned. If the request is not
// accessing a workspace app, then the next handler is called and false is
// returned.
func (s *Server) parseHostname(rw http.ResponseWriter, r *http.Request, next http.Handler, host string) (httpapi.ApplicationURL, bool) {
// Check if the hostname matches either of the access URLs. If it does, the
// user was definitely trying to connect to the dashboard/API or a
// path-based app.
if httpapi.HostnamesMatch(s.DashboardURL.Hostname(), host) || httpapi.HostnamesMatch(s.AccessURL.Hostname(), host) {
next.ServeHTTP(rw, r)
return httpapi.ApplicationURL{}, false
}
// If there are no periods in the hostname, then it can't be a valid
// application URL.
if !strings.Contains(host, ".") {
next.ServeHTTP(rw, r)
return httpapi.ApplicationURL{}, false
}
// Split the subdomain so we can parse the application details and verify it
// matches the configured app hostname later.
subdomain, ok := httpapi.ExecuteHostnamePattern(s.HostnameRegex, host)
if !ok {
// Doesn't match the regex, so it's not a valid application URL.
next.ServeHTTP(rw, r)
return httpapi.ApplicationURL{}, false
}
// Check if the request is part of the deprecated logout flow. If so, we
// just redirect to the main access URL.
if subdomain == appLogoutHostname {
http.Redirect(rw, r, s.AccessURL.String(), http.StatusSeeOther)
return httpapi.ApplicationURL{}, false
}
// Parse the application URL from the subdomain.
app, err := httpapi.ParseSubdomainAppURL(subdomain)
if err != nil {
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusBadRequest,
Title: "Invalid Application URL",
Description: fmt.Sprintf("Could not parse subdomain application URL %q: %s", subdomain, err.Error()),
RetryEnabled: false,
DashboardURL: s.DashboardURL.String(),
})
return httpapi.ApplicationURL{}, false
}
return app, true
}
func (s *Server) proxyWorkspaceApp(rw http.ResponseWriter, r *http.Request, appToken SignedToken, path string) {
ctx := r.Context()
// Filter IP headers from untrusted origins.
httpmw.FilterUntrustedOriginHeaders(s.RealIPConfig, r)
// Ensure proper IP headers get sent to the forwarded application.
err := httpmw.EnsureXForwardedForHeader(r)
if err != nil {
httpapi.InternalServerError(rw, err)
return
}
appURL, err := url.Parse(appToken.AppURL)
if err != nil {
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusBadRequest,
Title: "Bad Request",
Description: fmt.Sprintf("Application has an invalid URL %q: %s", appToken.AppURL, err.Error()),
RetryEnabled: true,
DashboardURL: s.DashboardURL.String(),
})
return
}
// Verify that the port is allowed. See the docs above
// `codersdk.MinimumListeningPort` for more details.
port := appURL.Port()
if port != "" {
portInt, err := strconv.Atoi(port)
if err != nil {
httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
Message: fmt.Sprintf("App URL %q has an invalid port %q.", appToken.AppURL, port),
Detail: err.Error(),
})
return
}
if portInt < codersdk.WorkspaceAgentMinimumListeningPort {
httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
Message: fmt.Sprintf("Application port %d is not permitted. Coder reserves ports less than %d for internal use.", portInt, codersdk.WorkspaceAgentMinimumListeningPort),
})
return
}
}
// Ensure path and query parameter correctness.
if path == "" {
// Web applications typically request paths relative to the
// root URL. This allows for routing behind a proxy or subpath.
// See https://github.com/coder/code-server/issues/241 for examples.
http.Redirect(rw, r, r.URL.Path+"/", http.StatusTemporaryRedirect)
return
}
if path == "/" && r.URL.RawQuery == "" && appURL.RawQuery != "" {
// If the application defines a default set of query parameters,
// we should always respect them. The reverse proxy will merge
// query parameters for server-side requests, but sometimes
// client-side applications require the query parameters to render
// properly. With code-server, this is the "folder" param.
r.URL.RawQuery = appURL.RawQuery
http.Redirect(rw, r, r.URL.String(), http.StatusTemporaryRedirect)
return
}
r.URL.Path = path
appURL.RawQuery = ""
proxy, release, err := s.AgentProvider.ReverseProxy(appURL, s.DashboardURL, appToken.AgentID)
if err != nil {
site.RenderStaticErrorPage(rw, r, site.ErrorPageData{
Status: http.StatusBadGateway,
Title: "Bad Gateway",
Description: "Could not connect to workspace agent: " + err.Error(),
RetryEnabled: true,
DashboardURL: s.DashboardURL.String(),
})
return
}
defer release()
proxy.ModifyResponse = func(r *http.Response) error {
r.Header.Del(httpmw.AccessControlAllowOriginHeader)
r.Header.Del(httpmw.AccessControlAllowCredentialsHeader)
r.Header.Del(httpmw.AccessControlAllowMethodsHeader)
r.Header.Del(httpmw.AccessControlAllowHeadersHeader)
varies := r.Header.Values(httpmw.VaryHeader)
r.Header.Del(httpmw.VaryHeader)
forbiddenVary := []string{
httpmw.OriginHeader,
httpmw.AccessControlRequestMethodsHeader,
httpmw.AccessControlRequestHeadersHeader,
}
for _, value := range varies {
if !slice.ContainsCompare(forbiddenVary, value, strings.EqualFold) {
r.Header.Add(httpmw.VaryHeader, value)
}
}
return nil
}
// This strips the session token from a workspace app request.
cookieHeaders := r.Header.Values("Cookie")[:]
r.Header.Del("Cookie")
for _, cookieHeader := range cookieHeaders {
r.Header.Add("Cookie", httpapi.StripCoderCookies(cookieHeader))
}
// Convert canonicalized headers to their non-canonicalized counterparts.
// See the comment on `nonCanonicalHeaders` for more information on why this
// is necessary.
for k, v := range r.Header {
if n, ok := nonCanonicalHeaders[k]; ok {
r.Header.Del(k)
r.Header[n] = v
}
}
// end span so we don't get long lived trace data
tracing.EndHTTPSpan(r, http.StatusOK, trace.SpanFromContext(ctx))
proxy.ServeHTTP(rw, r)
}
// workspaceAgentPTY spawns a PTY and pipes it over a WebSocket.
// This is used for the web terminal.
//
// @Summary Open PTY to workspace agent
// @ID open-pty-to-workspace-agent
// @Security CoderSessionToken
// @Tags Agents
// @Param workspaceagent path string true "Workspace agent ID" format(uuid)
// @Success 101
// @Router /workspaceagents/{workspaceagent}/pty [get]
func (s *Server) workspaceAgentPTY(rw http.ResponseWriter, r *http.Request) {
ctx := r.Context()
s.websocketWaitMutex.Lock()
s.websocketWaitGroup.Add(1)
s.websocketWaitMutex.Unlock()
defer s.websocketWaitGroup.Done()
appToken, ok := ResolveRequest(rw, r, ResolveRequestOptions{
Logger: s.Logger,
SignedTokenProvider: s.SignedTokenProvider,
DashboardURL: s.DashboardURL,
PathAppBaseURL: s.AccessURL,
AppHostname: s.Hostname,
AppRequest: Request{
AccessMethod: AccessMethodTerminal,
BasePath: r.URL.Path,
AgentNameOrID: chi.URLParam(r, "workspaceagent"),
},
AppPath: "",
AppQuery: "",
})
if !ok {
return
}
log := s.Logger.With(slog.F("agent_id", appToken.AgentID))
log.Debug(ctx, "resolved PTY request")
values := r.URL.Query()
parser := httpapi.NewQueryParamParser()
reconnect := parser.Required("reconnect").UUID(values, uuid.New(), "reconnect")
height := parser.UInt(values, 80, "height")
width := parser.UInt(values, 80, "width")
if len(parser.Errors) > 0 {
httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
Message: "Invalid query parameters.",
Validations: parser.Errors,
})
return
}
conn, err := websocket.Accept(rw, r, &websocket.AcceptOptions{
CompressionMode: websocket.CompressionDisabled,
// Always allow websockets from the primary dashboard URL.
// Terminals are opened there and connect to the proxy.
OriginPatterns: []string{
s.DashboardURL.Host,
s.AccessURL.Host,
},
})
if err != nil {
httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
Message: "Failed to accept websocket.",
Detail: err.Error(),
})
return
}
ctx, wsNetConn := WebsocketNetConn(ctx, conn, websocket.MessageBinary)
defer wsNetConn.Close() // Also closes conn.
go httpapi.Heartbeat(ctx, conn)
agentConn, release, err := s.AgentProvider.AgentConn(ctx, appToken.AgentID)
if err != nil {
log.Debug(ctx, "dial workspace agent", slog.Error(err))
_ = conn.Close(websocket.StatusInternalError, httpapi.WebsocketCloseSprintf("dial workspace agent: %s", err))
return
}
defer release()
defer agentConn.Close()
log.Debug(ctx, "dialed workspace agent")
ptNetConn, err := agentConn.ReconnectingPTY(ctx, reconnect, uint16(height), uint16(width), r.URL.Query().Get("command"))
if err != nil {
log.Debug(ctx, "dial reconnecting pty server in workspace agent", slog.Error(err))
_ = conn.Close(websocket.StatusInternalError, httpapi.WebsocketCloseSprintf("dial: %s", err))
return
}
defer ptNetConn.Close()
log.Debug(ctx, "obtained PTY")
agentssh.Bicopy(ctx, wsNetConn, ptNetConn)
log.Debug(ctx, "pty Bicopy finished")
}
// wsNetConn wraps net.Conn created by websocket.NetConn(). Cancel func
// is called if a read or write error is encountered.
type wsNetConn struct {
cancel context.CancelFunc
net.Conn
}
func (c *wsNetConn) Read(b []byte) (n int, err error) {
n, err = c.Conn.Read(b)
if err != nil {
c.cancel()
}
return n, err
}
func (c *wsNetConn) Write(b []byte) (n int, err error) {
n, err = c.Conn.Write(b)
if err != nil {
c.cancel()
}
return n, err
}
func (c *wsNetConn) Close() error {
defer c.cancel()
return c.Conn.Close()
}
// WebsocketNetConn wraps websocket.NetConn and returns a context that
// is tied to the parent context and the lifetime of the conn. Any error
// during read or write will cancel the context, but not close the
// conn. Close should be called to release context resources.
func WebsocketNetConn(ctx context.Context, conn *websocket.Conn, msgType websocket.MessageType) (context.Context, net.Conn) {
ctx, cancel := context.WithCancel(ctx)
nc := websocket.NetConn(ctx, conn, msgType)
return ctx, &wsNetConn{
cancel: cancel,
Conn: nc,
}
}