Added support for Websockets

cmd/handle_http_traffic.go

@@ -27,12 +27,27 @@ func handleHttpTraffic(wiretapConfig *shared.WiretapConfiguration, wtService *da
 			wtService.HandleHttpRequest(requestModel)
 		}
 
+		handleWebsocket := func(w http.ResponseWriter, r *http.Request) {
+			id, _ := uuid.NewUUID()
+			requestModel := &model.Request{
+				Id:                 &id,
+				HttpRequest:        r,
+				HttpResponseWriter: w,
+			}
+			wtService.HandleWebsocketRequest(requestModel)
+		}
+
 		// create a new mux.
 		mux := http.NewServeMux()
 
 		// handle the index
 		mux.HandleFunc("/", handleTraffic)
 
+		// Handle Websockets
+		for websocket := range wiretapConfig.WebsocketConfigs {
+			mux.HandleFunc(websocket, handleWebsocket)
+		}
+
 		pterm.Info.Println(pterm.LightMagenta(fmt.Sprintf("API Gateway UI booting on port %s...", wiretapConfig.Port)))
 
 		var httpErr error

cmd/root_command.go

@@ -349,6 +349,16 @@ var (
 				printLoadedRedirectAllowList(config.RedirectAllowList)
 			}
 
+			if len(config.WebsocketConfigs) > 0 {
+				for _, config := range config.WebsocketConfigs {
+					if config.VerifyCert == nil {
+						config.VerifyCert = func() *bool { b := true; return &b }()
+					}
+				}
+
+				printLoadedWebsockets(config.WebsocketConfigs)
+			}
+
 			// static headers
 			if config.Headers != nil && len(config.Headers.DropHeaders) > 0 {
 				pterm.Info.Printf("Dropping the following %d %s globally:\n", len(config.Headers.DropHeaders),
@@ -625,8 +635,7 @@ func Execute(version, commit, date string, fs embed.FS) {
 	rootCmd.Flags().IntP("hard-validation-code", "q", 400, "Set a custom http error code for non-compliant requests when using the hard-error flag")
 	rootCmd.Flags().IntP("hard-validation-return-code", "y", 502, "Set a custom http error code for non-compliant responses when using the hard-error flag")
 	rootCmd.Flags().BoolP("mock-mode", "x", false, "Run in mock mode, responses are mocked and no traffic is sent to the target API (requires OpenAPI spec)")
-	rootCmd.Flags().StringP("config", "c", "",
-		"Location of wiretap configuration file to use (default is .wiretap in current directory)")
+	rootCmd.Flags().StringP("config", "c", "", "Location of wiretap configuration file to use (default is .wiretap in current directory)")
 	rootCmd.Flags().StringP("base", "b", "", "Set a base path to resolve relative file references from, or a overriding base URL to resolve remote references from")
 	rootCmd.Flags().BoolP("debug", "l", false, "Enable debug logging")
 	rootCmd.Flags().StringP("har", "z", "", "Load a HAR file instead of sniffing traffic")
@@ -706,11 +715,20 @@ func printLoadedIgnoreRedirectPaths(ignoreRedirects []string) {
 }
 
 func printLoadedRedirectAllowList(allowRedirects []string) {
-	pterm.Info.Printf("Loaded %d allows listed redirect %s :\n", len(allowRedirects),
+	pterm.Info.Printf("Loaded %d allows listed redirect %s:\n", len(allowRedirects),
 		shared.Pluralize(len(allowRedirects), "path", "paths"))
 
 	for _, x := range allowRedirects {
 		pterm.Printf("🐵 Paths matching '%s' will always follow redirects, regardless of ignoreRedirect settings\n", pterm.LightCyan(x))
 	}
 	pterm.Println()
 }
+
+func printLoadedWebsockets(websockets map[string]*shared.WiretapWebsocketConfig) {
+	pterm.Info.Printf("Loaded %d %s: \n", len(websockets), shared.Pluralize(len(websockets), "websocket", "websockets"))
+
+	for websocket := range websockets {
+		pterm.Printf("🔌 Paths prefixed '%s' will be managed as a websocket\n", pterm.LightCyan(websocket))
+	}
+	pterm.Println()
+}

daemon/handle_request.go

@@ -4,8 +4,10 @@
 package daemon
 
 import (
+	"crypto/tls"
 	_ "embed"
 	"fmt"
+	"github.com/gorilla/websocket"
 	"io"
 	"net/http"
 	"os"
@@ -99,32 +101,7 @@ func (ws *WiretapService) handleHttpRequest(request *model.Request) {
 		}
 	}
 
-	var dropHeaders []string
-	var injectHeaders map[string]string
-
-	// add global headers with injection.
-	if config.Headers != nil {
-		dropHeaders = config.Headers.DropHeaders
-		injectHeaders = config.Headers.InjectHeaders
-	}
-
-	// now add path specific headers.
-	matchedPaths := configModel.FindPaths(request.HttpRequest.URL.Path, config)
-	auth := ""
-	if len(matchedPaths) > 0 {
-		for _, path := range matchedPaths {
-			auth = path.Auth
-			if path.Headers != nil {
-				dropHeaders = append(dropHeaders, path.Headers.DropHeaders...)
-				newInjectHeaders := path.Headers.InjectHeaders
-				for key := range injectHeaders {
-					newInjectHeaders[key] = injectHeaders[key]
-				}
-				injectHeaders = newInjectHeaders
-			}
-			break
-		}
-	}
+	dropHeaders, injectHeaders, auth := ws.getHeadersAndAuth(config, request)
 
 	newReq := CloneExistingRequest(CloneRequest{
 		Request:       request.HttpRequest,
@@ -238,8 +215,210 @@ func (ws *WiretapService) handleHttpRequest(request *model.Request) {
 	_, _ = request.HttpResponseWriter.Write(body)
 }
 
+var gorillaDropHeaders = []string{
+	// Gorilla fills in the following headers, and complains if they are already present
+	"Upgrade",
+	"Connection",
+	"Sec-Websocket-Key",
+	"Sec-Websocket-Version",
+	"Sec-Websocket-Protocol",
+	"Sec-Websocket-Extensions",
+}
+
+func (ws *WiretapService) handleWebsocketRequest(request *model.Request) {
+
+	configStore, _ := ws.controlsStore.Get(shared.ConfigKey)
+	config := configStore.(*shared.WiretapConfiguration)
+
+	// Get the Websocket Configuration
+	websocketUrl := request.HttpRequest.URL.String()
+	websocketConfig, ok := config.WebsocketConfigs[websocketUrl]
+	if !ok {
+		ws.config.Logger.Error(fmt.Sprintf("Unable to find websocket config for URL: %s", websocketUrl))
+	}
+
+	// There's nothing to do if we're in mock mode
+	if config.MockMode {
+		return
+	}
+
+	upgrader := websocket.Upgrader{
+		ReadBufferSize:  1024,
+		WriteBufferSize: 1024,
+	}
+
+	// Upgrade the connection from the client to open a websocket connection
+	clientConn, err := upgrader.Upgrade(request.HttpResponseWriter, request.HttpRequest, nil)
+	if err != nil {
+		ws.config.Logger.Error("Unable to upgrade websocket connection")
+		return
+	}
+	defer func(clientConn *websocket.Conn) {
+		_ = clientConn.Close()
+	}(clientConn)
+
+	if config.Headers == nil || len(config.Headers.DropHeaders) == 0 {
+		config.Headers = &shared.WiretapHeaderConfig{
+			DropHeaders: []string{},
+		}
+	}
+
+	// Get the updated headers and auth
+	dropHeaders, injectHeaders, auth := ws.getHeadersAndAuth(config, request)
+
+	dropHeaders = append(dropHeaders, gorillaDropHeaders...)
+	dropHeaders = append(dropHeaders, websocketConfig.DropHeaders...)
+
+	// Determine the correct websocket protocol based on redirect protocol
+	var protocol string
+	if config.RedirectProtocol == "https" {
+		protocol = "wss"
+	} else if config.RedirectProtocol == "http" {
+		protocol = "ws"
+	} else if config.RedirectProtocol != "wss" && config.RedirectProtocol != "ws" {
+		config.Logger.Error(fmt.Sprintf("Unsupported Redirect Protocol: %s", config.RedirectProtocol))
+		return
+	}
+
+	// Create a new request, which fills in the URL and other information
+	newRequest := CloneExistingRequest(CloneRequest{
+		Request:       request.HttpRequest,
+		Protocol:      protocol,
+		Host:          config.RedirectHost,
+		BasePath:      config.RedirectBasePath,
+		Port:          config.RedirectPort,
+		DropHeaders:   dropHeaders,
+		InjectHeaders: injectHeaders,
+		Auth:          auth,
+		Variables:     config.CompiledVariables,
+	})
+
+	// Open a new websocket connection with the server
+	dialer := *websocket.DefaultDialer
+	dialer.TLSClientConfig = &tls.Config{InsecureSkipVerify: !*websocketConfig.VerifyCert}
+	serverConn, _, err := dialer.Dial(newRequest.URL.String(), newRequest.Header)
+	if err != nil {
+		ws.config.Logger.Error("Unable to create server connection")
+		return
+	}
+	defer func(serverConn *websocket.Conn) {
+		_ = serverConn.Close()
+	}(serverConn)
+
+	// Create sentinel channels
+	clientSentinel := make(chan struct{})
+	serverSentinel := make(chan struct{})
+
+	// Go-Routine for communication between Client -> Server
+	go func() {
+		defer close(clientSentinel)
+
+		for {
+			messageType, message, err := clientConn.ReadMessage()
+			if err != nil {
+				closeCode, isUnexpected := getCloseCode(err)
+				logWebsocketClose(config, closeCode, isUnexpected)
+				_ = clientConn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
+				return
+			}
+
+			err = serverConn.WriteMessage(messageType, message)
+			if err != nil {
+				closeCode, isUnexpected := getCloseCode(err)
+				logWebsocketClose(config, closeCode, isUnexpected)
+				return
+			}
+		}
+	}()
+
+	// Go-Routine for communication between Server -> Client
+	go func() {
+		defer close(serverSentinel)
+
+		for {
+			messageType, message, err := serverConn.ReadMessage()
+			if err != nil {
+				closeCode, isUnexpected := getCloseCode(err)
+				logWebsocketClose(config, closeCode, isUnexpected)
+				_ = clientConn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
+				return
+			}
+
+			err = clientConn.WriteMessage(messageType, message)
+			if err != nil {
+				closeCode, isUnexpected := getCloseCode(err)
+				logWebsocketClose(config, closeCode, isUnexpected)
+				return
+			}
+		}
+	}()
+
+	// Loop until at least one of our sentinel channels have been closed
+	for {
+		select {
+		case <-clientSentinel:
+			return
+		case <-serverSentinel:
+			return
+		}
+	}
+}
+
 func setCORSHeaders(headers map[string][]string) {
 	headers["Access-Control-Allow-Headers"] = []string{"*"}
 	headers["Access-Control-Allow-Origin"] = []string{"*"}
 	headers["Access-Control-Allow-Methods"] = []string{"OPTIONS,POST,GET,DELETE,PATCH,PUT"}
 }
+
+func getCloseCode(err error) (int, bool) {
+	unexpectedClose := websocket.IsUnexpectedCloseError(err,
+		websocket.CloseNormalClosure,
+		websocket.CloseGoingAway,
+		websocket.CloseNoStatusReceived,
+		websocket.CloseAbnormalClosure,
+	)
+
+	if ce, ok := err.(*websocket.CloseError); ok {
+		return ce.Code, unexpectedClose
+	}
+	return -1, unexpectedClose
+}
+
+func logWebsocketClose(config *shared.WiretapConfiguration, closeCode int, isUnexpected bool) {
+	if isUnexpected {
+		config.Logger.Error(fmt.Sprintf("Websocket closed unexepectedly with code: %d", closeCode))
+	} else {
+		config.Logger.Info(fmt.Sprintf("Websocket closed expectedly with code: %d", closeCode))
+	}
+}
+
+func (ws *WiretapService) getHeadersAndAuth(config *shared.WiretapConfiguration, request *model.Request) ([]string, map[string]string, string) {
+	var dropHeaders []string
+	var injectHeaders map[string]string
+
+	// add global headers with injection.
+	if config.Headers != nil {
+		dropHeaders = config.Headers.DropHeaders
+		injectHeaders = config.Headers.InjectHeaders
+	}
+
+	// now add path specific headers.
+	matchedPaths := configModel.FindPaths(request.HttpRequest.URL.Path, config)
+	auth := ""
+	if len(matchedPaths) > 0 {
+		for _, path := range matchedPaths {
+			auth = path.Auth
+			if path.Headers != nil {
+				dropHeaders = append(dropHeaders, path.Headers.DropHeaders...)
+				newInjectHeaders := path.Headers.InjectHeaders
+				for key := range injectHeaders {
+					newInjectHeaders[key] = injectHeaders[key]
+				}
+				injectHeaders = newInjectHeaders
+			}
+			break
+		}
+	}
+
+	return dropHeaders, injectHeaders, auth
+}

daemon/wiretap_service.go

@@ -95,6 +95,9 @@ func (ws *WiretapService) HandleServiceRequest(request *model.Request, core serv
 }
 
 func (ws *WiretapService) HandleHttpRequest(request *model.Request) {
-
 	ws.handleHttpRequest(request)
 }
+
+func (ws *WiretapService) HandleWebsocketRequest(request *model.Request) {
+	ws.handleWebsocketRequest(request)
+}