fix(cdp): resolve issue 2 audit findings

Co-Authored-By: Virgil <virgil@lethean.io>

actions.go

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: EUPL-1.2
 package webview
 
 import (

angular.go

@@ -1,7 +1,9 @@
+// SPDX-License-Identifier: EUPL-1.2
 package webview
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"strings"
 	"time"
@@ -93,6 +95,21 @@ func (ah *AngularHelper) isAngularApp(ctx context.Context) (bool, error) {
 func (ah *AngularHelper) waitForZoneStability(ctx context.Context) error {
 	script := `
 		new Promise((resolve, reject) => {
+			const pollZone = () => {
+				if (!window.Zone || !window.Zone.current) {
+					resolve(true);
+					return;
+				}
+
+				const inner = window.Zone.current._inner || window.Zone.current;
+				if (!inner._hasPendingMicrotasks && !inner._hasPendingMacrotasks) {
+					resolve(true);
+					return;
+				}
+
+				setTimeout(pollZone, 50);
+			};
+
 			// Get the root elements
 			const roots = window.getAllAngularRootElements ? window.getAllAngularRootElements() : [];
 			if (roots.length === 0) {
@@ -121,28 +138,7 @@ func (ah *AngularHelper) waitForZoneStability(ctx context.Context) error {
 			}
 
 			if (!zone) {
-				// Fallback: check window.Zone
-				if (window.Zone && window.Zone.current && window.Zone.current._inner) {
-					const isStable = !window.Zone.current._inner._hasPendingMicrotasks &&
-						!window.Zone.current._inner._hasPendingMacrotasks;
-					if (isStable) {
-						resolve(true);
-					} else {
-						// Poll for stability
-						let attempts = 0;
-						const poll = setInterval(() => {
-							attempts++;
-							const stable = !window.Zone.current._inner._hasPendingMicrotasks &&
-								!window.Zone.current._inner._hasPendingMacrotasks;
-							if (stable || attempts > 100) {
-								clearInterval(poll);
-								resolve(stable);
-							}
-						}, 50);
-					}
-				} else {
-					resolve(true);
-				}
+				pollZone();
 				return;
 			}
 
@@ -153,30 +149,28 @@ func (ah *AngularHelper) waitForZoneStability(ctx context.Context) error {
 			}
 
 			// Wait for stability
-			const sub = zone.onStable.subscribe(() => {
-				sub.unsubscribe();
-				resolve(true);
-			});
-
-			// Timeout fallback
-			setTimeout(() => {
-				sub.unsubscribe();
-				resolve(zone.isStable);
-			}, 5000);
+			try {
+				const sub = zone.onStable.subscribe(() => {
+					sub.unsubscribe();
+					resolve(true);
+				});
+			} catch (e) {
+				pollZone();
+			}
 		})
 	`
 
-	ticker := time.NewTicker(100 * time.Millisecond)
-	defer ticker.Stop()
-
-	// First evaluate the promise
-	_, err := ah.wv.evaluate(ctx, script)
+	result, err := ah.wv.evaluate(ctx, script)
 	if err != nil {
 		// If the script fails, fall back to simple polling
 		return ah.pollForStability(ctx)
 	}
 
-	return nil
+	if stable, ok := result.(bool); ok && stable {
+		return nil
+	}
+
+	return ah.pollForStability(ctx)
 }
 
 // pollForStability polls for Angular stability as a fallback.
@@ -333,18 +327,20 @@ func (ah *AngularHelper) GetComponentProperty(selector, propertyName string) (an
 	defer cancel()
 
 	script := fmt.Sprintf(`
-		(function() {
-			const element = document.querySelector(%q);
-			if (!element) {
-				throw new Error('Element not found: %s');
-			}
-			const component = window.ng.probe(element).componentInstance;
-			if (!component) {
-				throw new Error('No Angular component found on element');
-			}
-			return component[%q];
-		})()
-	`, selector, selector, propertyName)
+			(function() {
+				const selector = %s;
+				const propertyName = %s;
+				const element = document.querySelector(selector);
+				if (!element) {
+					throw new Error('Element not found: ' + selector);
+				}
+				const component = window.ng.probe(element).componentInstance;
+				if (!component) {
+					throw new Error('No Angular component found on element');
+				}
+				return component[propertyName];
+			})()
+		`, formatJSValue(selector), formatJSValue(propertyName))
 
 	return ah.wv.evaluate(ctx, script)
 }
@@ -355,26 +351,28 @@ func (ah *AngularHelper) SetComponentProperty(selector, propertyName string, val
 	defer cancel()
 
 	script := fmt.Sprintf(`
-		(function() {
-			const element = document.querySelector(%q);
-			if (!element) {
-				throw new Error('Element not found: %s');
-			}
-			const component = window.ng.probe(element).componentInstance;
-			if (!component) {
-				throw new Error('No Angular component found on element');
-			}
-			component[%q] = %v;
+			(function() {
+				const selector = %s;
+				const propertyName = %s;
+				const element = document.querySelector(selector);
+				if (!element) {
+					throw new Error('Element not found: ' + selector);
+				}
+				const component = window.ng.probe(element).componentInstance;
+				if (!component) {
+					throw new Error('No Angular component found on element');
+				}
+				component[propertyName] = %s;
 
-			// Trigger change detection
-			const injector = window.ng.probe(element).injector;
-			const appRef = injector.get(window.ng.coreTokens.ApplicationRef || 'ApplicationRef');
-			if (appRef) {
+				// Trigger change detection
+				const injector = window.ng.probe(element).injector;
+				const appRef = injector.get(window.ng.coreTokens.ApplicationRef || 'ApplicationRef');
+				if (appRef) {
 				appRef.tick();
-			}
-			return true;
-		})()
-	`, selector, selector, propertyName, formatJSValue(value))
+				}
+				return true;
+			})()
+		`, formatJSValue(selector), formatJSValue(propertyName), formatJSValue(value))
 
 	_, err := ah.wv.evaluate(ctx, script)
 	return err
@@ -394,29 +392,31 @@ func (ah *AngularHelper) CallComponentMethod(selector, methodName string, args .
 	}
 
 	script := fmt.Sprintf(`
-		(function() {
-			const element = document.querySelector(%q);
-			if (!element) {
-				throw new Error('Element not found: %s');
-			}
-			const component = window.ng.probe(element).componentInstance;
-			if (!component) {
-				throw new Error('No Angular component found on element');
-			}
-			if (typeof component[%q] !== 'function') {
-				throw new Error('Method not found: %s');
-			}
-			const result = component[%q](%s);
+			(function() {
+				const selector = %s;
+				const methodName = %s;
+				const element = document.querySelector(selector);
+				if (!element) {
+					throw new Error('Element not found: ' + selector);
+				}
+				const component = window.ng.probe(element).componentInstance;
+				if (!component) {
+					throw new Error('No Angular component found on element');
+				}
+				if (typeof component[methodName] !== 'function') {
+					throw new Error('Method not found: ' + methodName);
+				}
+				const result = component[methodName](%s);
 
-			// Trigger change detection
-			const injector = window.ng.probe(element).injector;
-			const appRef = injector.get(window.ng.coreTokens.ApplicationRef || 'ApplicationRef');
-			if (appRef) {
+				// Trigger change detection
+				const injector = window.ng.probe(element).injector;
+				const appRef = injector.get(window.ng.coreTokens.ApplicationRef || 'ApplicationRef');
+				if (appRef) {
 				appRef.tick();
-			}
-			return result;
-		})()
-	`, selector, selector, methodName, methodName, methodName, argsStr.String())
+				}
+				return result;
+			})()
+		`, formatJSValue(selector), formatJSValue(methodName), argsStr.String())
 
 	return ah.wv.evaluate(ctx, script)
 }
@@ -524,16 +524,18 @@ func (ah *AngularHelper) DispatchEvent(selector, eventName string, detail any) e
 	}
 
 	script := fmt.Sprintf(`
-		(function() {
-			const element = document.querySelector(%q);
-			if (!element) {
-				throw new Error('Element not found: %s');
-			}
-			const event = new CustomEvent(%q, { bubbles: true, detail: %s });
-			element.dispatchEvent(event);
-			return true;
-		})()
-	`, selector, selector, eventName, detailStr)
+			(function() {
+				const selector = %s;
+				const eventName = %s;
+				const element = document.querySelector(selector);
+				if (!element) {
+					throw new Error('Element not found: ' + selector);
+				}
+				const event = new CustomEvent(eventName, { bubbles: true, detail: %s });
+				element.dispatchEvent(event);
+				return true;
+			})()
+		`, formatJSValue(selector), formatJSValue(eventName), detailStr)
 
 	_, err := ah.wv.evaluate(ctx, script)
 	return err
@@ -572,17 +574,18 @@ func (ah *AngularHelper) SetNgModel(selector string, value any) error {
 	defer cancel()
 
 	script := fmt.Sprintf(`
-		(function() {
-			const element = document.querySelector(%q);
-			if (!element) {
-				throw new Error('Element not found: %s');
-			}
+			(function() {
+				const selector = %s;
+				const element = document.querySelector(selector);
+				if (!element) {
+					throw new Error('Element not found: ' + selector);
+				}
 
-			element.value = %v;
-			element.dispatchEvent(new Event('input', { bubbles: true }));
-			element.dispatchEvent(new Event('change', { bubbles: true }));
+				element.value = %s;
+				element.dispatchEvent(new Event('input', { bubbles: true }));
+				element.dispatchEvent(new Event('change', { bubbles: true }));
 
-			// Trigger change detection
+				// Trigger change detection
 			const roots = window.getAllAngularRootElements ? window.getAllAngularRootElements() : [];
 			for (const root of roots) {
 				try {
@@ -595,9 +598,9 @@ func (ah *AngularHelper) SetNgModel(selector string, value any) error {
 				} catch (e) {}
 			}
 
-			return true;
-		})()
-	`, selector, selector, formatJSValue(value))
+				return true;
+			})()
+		`, formatJSValue(selector), formatJSValue(value))
 
 	_, err := ah.wv.evaluate(ctx, script)
 	return err
@@ -613,17 +616,15 @@ func getString(m map[string]any, key string) string {
 }
 
 func formatJSValue(v any) string {
-	switch val := v.(type) {
-	case string:
-		return fmt.Sprintf("%q", val)
-	case bool:
-		if val {
-			return "true"
-		}
-		return "false"
-	case nil:
-		return "null"
-	default:
-		return fmt.Sprintf("%v", val)
+	data, err := json.Marshal(v)
+	if err == nil {
+		return string(data)
 	}
+
+	fallback, fallbackErr := json.Marshal(fmt.Sprint(v))
+	if fallbackErr == nil {
+		return string(fallback)
+	}
+
+	return "null"
 }

audit_issue2_test.go

@@ -0,0 +1,673 @@
+// SPDX-License-Identifier: EUPL-1.2
+package webview
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/gorilla/websocket"
+)
+
+type fakeCDPServer struct {
+	t          *testing.T
+	server     *httptest.Server
+	mu         sync.Mutex
+	nextTarget int
+	targets    map[string]*fakeCDPTarget
+}
+
+type fakeCDPTarget struct {
+	server        *fakeCDPServer
+	id            string
+	onConnect     func(*fakeCDPTarget)
+	onMessage     func(*fakeCDPTarget, cdpMessage)
+	connMu        sync.Mutex
+	conn          *websocket.Conn
+	received      chan cdpMessage
+	connected     chan struct{}
+	closed        chan struct{}
+	connectedOnce sync.Once
+	closedOnce    sync.Once
+}
+
+func newFakeCDPServer(t *testing.T) *fakeCDPServer {
+	t.Helper()
+
+	server := &fakeCDPServer{
+		t:       t,
+		targets: make(map[string]*fakeCDPTarget),
+	}
+	server.server = httptest.NewServer(http.HandlerFunc(server.handle))
+	server.addTarget("target-1")
+	t.Cleanup(server.Close)
+
+	return server
+}
+
+func (s *fakeCDPServer) Close() {
+	s.server.Close()
+}
+
+func (s *fakeCDPServer) DebugURL() string {
+	return s.server.URL
+}
+
+func (s *fakeCDPServer) addTarget(id string) *fakeCDPTarget {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	target := &fakeCDPTarget{
+		server:    s,
+		id:        id,
+		received:  make(chan cdpMessage, 16),
+		connected: make(chan struct{}),
+		closed:    make(chan struct{}),
+	}
+	s.targets[id] = target
+	return target
+}
+
+func (s *fakeCDPServer) newTarget() *fakeCDPTarget {
+	s.mu.Lock()
+	s.nextTarget++
+	id := fmt.Sprintf("target-%d", s.nextTarget+1)
+	s.mu.Unlock()
+
+	return s.addTarget(id)
+}
+
+func (s *fakeCDPServer) primaryTarget() *fakeCDPTarget {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.targets["target-1"]
+}
+
+func (s *fakeCDPServer) handle(w http.ResponseWriter, r *http.Request) {
+	switch {
+	case r.URL.Path == "/json":
+		s.handleListTargets(w)
+	case r.URL.Path == "/json/new":
+		s.handleNewTarget(w)
+	case r.URL.Path == "/json/version":
+		s.writeJSON(w, map[string]string{
+			"Browser": "Chrome/123.0",
+		})
+	case strings.HasPrefix(r.URL.Path, "/devtools/page/"):
+		s.handleWebSocket(w, r, strings.TrimPrefix(r.URL.Path, "/devtools/page/"))
+	default:
+		http.NotFound(w, r)
+	}
+}
+
+func (s *fakeCDPServer) handleListTargets(w http.ResponseWriter) {
+	s.mu.Lock()
+	targets := make([]TargetInfo, 0, len(s.targets))
+	for id := range s.targets {
+		targets = append(targets, TargetInfo{
+			ID:                   id,
+			Type:                 "page",
+			Title:                id,
+			URL:                  "about:blank",
+			WebSocketDebuggerURL: s.webSocketURL(id),
+		})
+	}
+	s.mu.Unlock()
+
+	s.writeJSON(w, targets)
+}
+
+func (s *fakeCDPServer) handleNewTarget(w http.ResponseWriter) {
+	target := s.newTarget()
+	s.writeJSON(w, TargetInfo{
+		ID:                   target.id,
+		Type:                 "page",
+		Title:                target.id,
+		URL:                  "about:blank",
+		WebSocketDebuggerURL: s.webSocketURL(target.id),
+	})
+}
+
+func (s *fakeCDPServer) handleWebSocket(w http.ResponseWriter, r *http.Request, id string) {
+	s.mu.Lock()
+	target := s.targets[id]
+	s.mu.Unlock()
+	if target == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	upgrader := websocket.Upgrader{
+		CheckOrigin: func(*http.Request) bool { return true },
+	}
+	conn, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		s.t.Fatalf("failed to upgrade test WebSocket: %v", err)
+	}
+
+	target.attach(conn)
+}
+
+func (s *fakeCDPServer) writeJSON(w http.ResponseWriter, value any) {
+	s.t.Helper()
+
+	w.Header().Set("Content-Type", "application/json")
+	if err := json.NewEncoder(w).Encode(value); err != nil {
+		s.t.Fatalf("failed to encode JSON: %v", err)
+	}
+}
+
+func (s *fakeCDPServer) webSocketURL(id string) string {
+	wsURL, err := url.Parse(s.server.URL)
+	if err != nil {
+		s.t.Fatalf("failed to parse test server URL: %v", err)
+	}
+	if wsURL.Scheme == "http" {
+		wsURL.Scheme = "ws"
+	} else {
+		wsURL.Scheme = "wss"
+	}
+	wsURL.Path = "/devtools/page/" + id
+	wsURL.RawQuery = ""
+	wsURL.Fragment = ""
+
+	return wsURL.String()
+}
+
+func (tgt *fakeCDPTarget) attach(conn *websocket.Conn) {
+	tgt.connMu.Lock()
+	tgt.conn = conn
+	tgt.connMu.Unlock()
+
+	tgt.connectedOnce.Do(func() {
+		close(tgt.connected)
+	})
+
+	go tgt.readLoop()
+
+	if tgt.onConnect != nil {
+		go tgt.onConnect(tgt)
+	}
+}
+
+func (tgt *fakeCDPTarget) readLoop() {
+	defer tgt.closedOnce.Do(func() {
+		close(tgt.closed)
+	})
+
+	for {
+		_, data, err := tgt.conn.ReadMessage()
+		if err != nil {
+			return
+		}
+
+		var msg cdpMessage
+		if err := json.Unmarshal(data, &msg); err != nil {
+			continue
+		}
+
+		select {
+		case tgt.received <- msg:
+		default:
+		}
+
+		if tgt.onMessage != nil {
+			tgt.onMessage(tgt, msg)
+		}
+	}
+}
+
+func (tgt *fakeCDPTarget) reply(id int64, result map[string]any) {
+	tgt.writeJSON(cdpResponse{
+		ID:     id,
+		Result: result,
+	})
+}
+
+func (tgt *fakeCDPTarget) replyError(id int64, message string) {
+	tgt.writeJSON(cdpResponse{
+		ID: id,
+		Error: &cdpError{
+			Message: message,
+		},
+	})
+}
+
+func (tgt *fakeCDPTarget) replyValue(id int64, value any) {
+	tgt.reply(id, map[string]any{
+		"result": map[string]any{
+			"value": value,
+		},
+	})
+}
+
+func (tgt *fakeCDPTarget) writeJSON(value any) {
+	tgt.server.t.Helper()
+
+	tgt.connMu.Lock()
+	defer tgt.connMu.Unlock()
+	if tgt.conn == nil {
+		tgt.server.t.Fatal("test WebSocket connection was not established")
+	}
+	if err := tgt.conn.WriteJSON(value); err != nil {
+		tgt.server.t.Fatalf("failed to write test WebSocket message: %v", err)
+	}
+}
+
+func (tgt *fakeCDPTarget) closeWebSocket() {
+	tgt.connMu.Lock()
+	defer tgt.connMu.Unlock()
+	if tgt.conn != nil {
+		_ = tgt.conn.Close()
+	}
+}
+
+func (tgt *fakeCDPTarget) waitForMessage(tb testing.TB) cdpMessage {
+	tb.Helper()
+
+	select {
+	case msg := <-tgt.received:
+		return msg
+	case <-time.After(time.Second):
+		tb.Fatal("timed out waiting for CDP message")
+		return cdpMessage{}
+	}
+}
+
+func (tgt *fakeCDPTarget) waitConnected(tb testing.TB) {
+	tb.Helper()
+
+	select {
+	case <-tgt.connected:
+	case <-time.After(time.Second):
+		tb.Fatal("timed out waiting for WebSocket connection")
+	}
+}
+
+func (tgt *fakeCDPTarget) waitClosed(tb testing.TB) {
+	tb.Helper()
+
+	select {
+	case <-tgt.closed:
+	case <-time.After(time.Second):
+		tb.Fatal("timed out waiting for WebSocket closure")
+	}
+}
+
+func TestCDPClientClose_Good_UnblocksReadLoop(t *testing.T) {
+	server := newFakeCDPServer(t)
+	target := server.primaryTarget()
+
+	client, err := NewCDPClient(server.DebugURL())
+	if err != nil {
+		t.Fatalf("NewCDPClient returned error: %v", err)
+	}
+
+	target.waitConnected(t)
+
+	done := make(chan error, 1)
+	go func() {
+		done <- client.Close()
+	}()
+
+	select {
+	case err := <-done:
+		if err != nil {
+			t.Fatalf("Close returned error: %v", err)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("Close blocked waiting for readLoop")
+	}
+}
+
+func TestCDPClientReadLoop_Ugly_StopsOnTerminalReadError(t *testing.T) {
+	server := newFakeCDPServer(t)
+	target := server.primaryTarget()
+	target.onConnect = func(target *fakeCDPTarget) {
+		target.closeWebSocket()
+	}
+
+	client, err := NewCDPClient(server.DebugURL())
+	if err != nil {
+		t.Fatalf("NewCDPClient returned error: %v", err)
+	}
+
+	select {
+	case <-client.done:
+	case <-time.After(time.Second):
+		t.Fatal("readLoop did not stop after terminal read error")
+	}
+}
+
+func TestCDPClientCloseTab_Good_ClosesTargetOnly(t *testing.T) {
+	server := newFakeCDPServer(t)
+	target := server.primaryTarget()
+	target.onMessage = func(target *fakeCDPTarget, msg cdpMessage) {
+		if msg.Method != "Target.closeTarget" {
+			t.Fatalf("CloseTab sent %q, want Target.closeTarget", msg.Method)
+		}
+		if got := msg.Params["targetId"]; got != target.id {
+			t.Fatalf("Target.closeTarget targetId = %v, want %q", got, target.id)
+		}
+		target.reply(msg.ID, map[string]any{"success": true})
+		go func() {
+			time.Sleep(10 * time.Millisecond)
+			target.closeWebSocket()
+		}()
+	}
+
+	client, err := NewCDPClient(server.DebugURL())
+	if err != nil {
+		t.Fatalf("NewCDPClient returned error: %v", err)
+	}
+
+	if err := client.CloseTab(); err != nil {
+		t.Fatalf("CloseTab returned error: %v", err)
+	}
+
+	msg := target.waitForMessage(t)
+	if msg.Method == "Browser.close" {
+		t.Fatal("CloseTab closed the whole browser")
+	}
+}
+
+func TestCDPClientDispatchEvent_Good_HandlerParamsAreIsolated(t *testing.T) {
+	client := &CDPClient{
+		handlers: make(map[string][]func(map[string]any)),
+	}
+
+	firstDone := make(chan map[string]any, 1)
+	secondDone := make(chan map[string]any, 1)
+
+	client.OnEvent("Runtime.testEvent", func(params map[string]any) {
+		params["value"] = "mutated"
+		params["nested"].(map[string]any)["count"] = 1
+		params["items"].([]any)[0].(map[string]any)["id"] = "changed"
+		firstDone <- params
+	})
+	client.OnEvent("Runtime.testEvent", func(params map[string]any) {
+		secondDone <- params
+	})
+
+	original := map[string]any{
+		"nested": map[string]any{"count": 0},
+		"items":  []any{map[string]any{"id": "original"}},
+	}
+
+	client.dispatchEvent("Runtime.testEvent", original)
+
+	select {
+	case <-firstDone:
+	case <-time.After(time.Second):
+		t.Fatal("first handler did not run")
+	}
+
+	var secondParams map[string]any
+	select {
+	case secondParams = <-secondDone:
+	case <-time.After(time.Second):
+		t.Fatal("second handler did not run")
+	}
+
+	if _, ok := secondParams["value"]; ok {
+		t.Fatal("second handler observed first handler mutation")
+	}
+	if got := secondParams["nested"].(map[string]any)["count"]; got != 0 {
+		t.Fatalf("second handler nested count = %v, want 0", got)
+	}
+	if got := secondParams["items"].([]any)[0].(map[string]any)["id"]; got != "original" {
+		t.Fatalf("second handler slice payload = %v, want %q", got, "original")
+	}
+	if got := original["nested"].(map[string]any)["count"]; got != 0 {
+		t.Fatalf("original params were mutated: nested count = %v", got)
+	}
+}
+
+func TestNewCDPClient_Bad_RejectsCrossHostWebSocket(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/json" {
+			http.NotFound(w, r)
+			return
+		}
+		w.Header().Set("Content-Type", "application/json")
+		if err := json.NewEncoder(w).Encode([]TargetInfo{{
+			ID:                   "target-1",
+			Type:                 "page",
+			WebSocketDebuggerURL: "ws://example.com/devtools/page/target-1",
+		}}); err != nil {
+			t.Fatalf("failed to encode targets: %v", err)
+		}
+	}))
+	defer server.Close()
+
+	_, err := NewCDPClient(server.URL)
+	if err == nil {
+		t.Fatal("NewCDPClient succeeded with a cross-host WebSocket URL")
+	}
+	if !strings.Contains(err.Error(), "invalid target WebSocket URL") {
+		t.Fatalf("NewCDPClient error = %v, want cross-host WebSocket validation failure", err)
+	}
+}
+
+func TestWebviewNew_Bad_ClosesClientWhenEnableConsoleFails(t *testing.T) {
+	server := newFakeCDPServer(t)
+	target := server.primaryTarget()
+	target.onMessage = func(target *fakeCDPTarget, msg cdpMessage) {
+		if msg.Method != "Runtime.enable" {
+			t.Fatalf("enableConsole sent %q before Runtime.enable failed", msg.Method)
+		}
+		target.replyError(msg.ID, "runtime disabled")
+	}
+
+	_, err := New(
+		WithTimeout(250*time.Millisecond),
+		WithDebugURL(server.DebugURL()),
+	)
+	if err == nil {
+		t.Fatal("New succeeded when Runtime.enable failed")
+	}
+
+	target.waitClosed(t)
+}
+
+func TestAngularHelperWaitForZoneStability_Good_AwaitsPromise(t *testing.T) {
+	server := newFakeCDPServer(t)
+	target := server.primaryTarget()
+	target.onMessage = func(target *fakeCDPTarget, msg cdpMessage) {
+		if msg.Method != "Runtime.evaluate" {
+			t.Fatalf("unexpected method %q", msg.Method)
+		}
+		target.replyValue(msg.ID, true)
+	}
+
+	client, err := NewCDPClient(server.DebugURL())
+	if err != nil {
+		t.Fatalf("NewCDPClient returned error: %v", err)
+	}
+	defer func() { _ = client.Close() }()
+
+	wv := &Webview{
+		client:  client,
+		ctx:     context.Background(),
+		timeout: time.Second,
+	}
+	ah := NewAngularHelper(wv)
+
+	if err := ah.waitForZoneStability(context.Background()); err != nil {
+		t.Fatalf("waitForZoneStability returned error: %v", err)
+	}
+
+	msg := target.waitForMessage(t)
+	if got := msg.Params["awaitPromise"]; got != true {
+		t.Fatalf("Runtime.evaluate awaitPromise = %v, want true", got)
+	}
+	if got := msg.Params["returnByValue"]; got != true {
+		t.Fatalf("Runtime.evaluate returnByValue = %v, want true", got)
+	}
+}
+
+func TestAngularHelperSetNgModel_Good_EscapesSelectorAndValue(t *testing.T) {
+	server := newFakeCDPServer(t)
+	target := server.primaryTarget()
+	target.onMessage = func(target *fakeCDPTarget, msg cdpMessage) {
+		if msg.Method != "Runtime.evaluate" {
+			t.Fatalf("unexpected method %q", msg.Method)
+		}
+		target.replyValue(msg.ID, true)
+	}
+
+	client, err := NewCDPClient(server.DebugURL())
+	if err != nil {
+		t.Fatalf("NewCDPClient returned error: %v", err)
+	}
+	defer func() { _ = client.Close() }()
+
+	wv := &Webview{
+		client:  client,
+		ctx:     context.Background(),
+		timeout: time.Second,
+	}
+	ah := NewAngularHelper(wv)
+
+	selector := `input[name="x'];window.hacked=true;//"]`
+	value := `";window.hacked=true;//`
+	if err := ah.SetNgModel(selector, value); err != nil {
+		t.Fatalf("SetNgModel returned error: %v", err)
+	}
+
+	expression, _ := target.waitForMessage(t).Params["expression"].(string)
+	if !strings.Contains(expression, "const selector = "+formatJSValue(selector)+";") {
+		t.Fatalf("expression did not contain safely quoted selector: %s", expression)
+	}
+	if !strings.Contains(expression, "element.value = "+formatJSValue(value)+";") {
+		t.Fatalf("expression did not contain safely quoted value: %s", expression)
+	}
+	if strings.Contains(expression, "throw new Error('Element not found: "+selector+"')") {
+		t.Fatalf("expression still embedded selector directly in error text: %s", expression)
+	}
+}
+
+func TestConsoleWatcherWaitForMessage_Good_IsolatesTemporaryHandlers(t *testing.T) {
+	cw := &ConsoleWatcher{
+		messages: make([]ConsoleMessage, 0),
+		filters:  make([]ConsoleFilter, 0),
+		limit:    1000,
+		handlers: make([]consoleHandlerRegistration, 0),
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	results := make(chan string, 2)
+	errorsCh := make(chan error, 2)
+
+	go func() {
+		msg, err := cw.WaitForMessage(ctx, ConsoleFilter{Type: "error"})
+		if err != nil {
+			errorsCh <- err
+			return
+		}
+		results <- "error:" + msg.Text
+	}()
+	go func() {
+		msg, err := cw.WaitForMessage(ctx, ConsoleFilter{Type: "log"})
+		if err != nil {
+			errorsCh <- err
+			return
+		}
+		results <- "log:" + msg.Text
+	}()
+
+	time.Sleep(20 * time.Millisecond)
+	cw.addMessage(ConsoleMessage{Type: "error", Text: "first"})
+	time.Sleep(20 * time.Millisecond)
+	cw.addMessage(ConsoleMessage{Type: "log", Text: "second"})
+
+	got := make(map[string]bool, 2)
+	for range 2 {
+		select {
+		case err := <-errorsCh:
+			t.Fatalf("WaitForMessage returned error: %v", err)
+		case result := <-results:
+			got[result] = true
+		case <-time.After(time.Second):
+			t.Fatal("timed out waiting for console waiter results")
+		}
+	}
+
+	if !got["error:first"] || !got["log:second"] {
+		t.Fatalf("unexpected console waiter results: %#v", got)
+	}
+	if len(cw.handlers) != 0 {
+		t.Fatalf("temporary handlers leaked: %d", len(cw.handlers))
+	}
+}
+
+func TestExceptionWatcherWaitForException_Good_PreservesExistingHandlers(t *testing.T) {
+	ew := &ExceptionWatcher{
+		exceptions: make([]ExceptionInfo, 0),
+		handlers:   make([]exceptionHandlerRegistration, 0),
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+	defer cancel()
+
+	waitDone := make(chan error, 1)
+	go func() {
+		_, err := ew.WaitForException(ctx)
+		waitDone <- err
+	}()
+
+	time.Sleep(20 * time.Millisecond)
+
+	var mu sync.Mutex
+	count := 0
+	ew.AddHandler(func(ExceptionInfo) {
+		mu.Lock()
+		defer mu.Unlock()
+		count++
+	})
+
+	ew.handleException(map[string]any{
+		"exceptionDetails": map[string]any{
+			"text":         "first",
+			"lineNumber":   float64(1),
+			"columnNumber": float64(1),
+			"url":          "https://example.com/app.js",
+		},
+	})
+
+	select {
+	case err := <-waitDone:
+		if err != nil {
+			t.Fatalf("WaitForException returned error: %v", err)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("timed out waiting for exception waiter")
+	}
+
+	ew.handleException(map[string]any{
+		"exceptionDetails": map[string]any{
+			"text":         "second",
+			"lineNumber":   float64(2),
+			"columnNumber": float64(1),
+			"url":          "https://example.com/app.js",
+		},
+	})
+
+	mu.Lock()
+	defer mu.Unlock()
+	if count != 2 {
+		t.Fatalf("persistent handler count = %d, want 2", count)
+	}
+	if len(ew.handlers) != 1 {
+		t.Fatalf("unexpected handler count after waiter removal: %d", len(ew.handlers))
+	}
+}

cdp.go

@@ -1,26 +1,46 @@
+// SPDX-License-Identifier: EUPL-1.2
 package webview
 
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"io"
 	"iter"
+	"net"
 	"net/http"
+	"net/url"
+	"path"
 	"slices"
+	"strings"
 	"sync"
 	"sync/atomic"
+	"time"
 
 	"github.com/gorilla/websocket"
 
 	coreerr "dappco.re/go/core/log"
 )
 
+const debugEndpointTimeout = 10 * time.Second
+
+var (
+	defaultDebugHTTPClient = &http.Client{
+		Timeout: debugEndpointTimeout,
+		CheckRedirect: func(*http.Request, []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	errCDPClientClosed = errors.New("cdp client closed")
+)
+
 // CDPClient handles communication with Chrome DevTools Protocol via WebSocket.
 type CDPClient struct {
-	mu       sync.RWMutex
-	conn     *websocket.Conn
-	debugURL string
-	wsURL    string
+	mu        sync.RWMutex
+	conn      *websocket.Conn
+	debugURL  string
+	debugBase *url.URL
+	wsURL     string
 
 	// Message tracking
 	msgID   atomic.Int64
@@ -32,9 +52,11 @@ type CDPClient struct {
 	handMu   sync.RWMutex
 
 	// Lifecycle
-	ctx    context.Context
-	cancel context.CancelFunc
-	done   chan struct{}
+	ctx       context.Context
+	cancel    context.CancelFunc
+	done      chan struct{}
+	closeOnce sync.Once
+	closeErr  error
 }
 
 // cdpMessage represents a CDP protocol message.
@@ -76,51 +98,41 @@ type TargetInfo struct {
 // NewCDPClient creates a new CDP client connected to the given debug URL.
 // The debug URL should be the Chrome DevTools HTTP endpoint (e.g., http://localhost:9222).
 func NewCDPClient(debugURL string) (*CDPClient, error) {
-	// Get available targets
-	resp, err := http.Get(debugURL + "/json")
+	debugBase, err := parseDebugURL(debugURL)
+	if err != nil {
+		return nil, coreerr.E("CDPClient.New", "invalid debug URL", err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), debugEndpointTimeout)
+	defer cancel()
+
+	targets, err := listTargetsAt(ctx, debugBase)
 	if err != nil {
 		return nil, coreerr.E("CDPClient.New", "failed to get targets", err)
 	}
-	defer func() { _ = resp.Body.Close() }()
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, coreerr.E("CDPClient.New", "failed to read targets", err)
-	}
-
-	var targets []TargetInfo
-	if err := json.Unmarshal(body, &targets); err != nil {
-		return nil, coreerr.E("CDPClient.New", "failed to parse targets", err)
-	}
 
 	// Find a page target
 	var wsURL string
 	for _, t := range targets {
 		if t.Type == "page" && t.WebSocketDebuggerURL != "" {
-			wsURL = t.WebSocketDebuggerURL
+			wsURL, err = validateTargetWebSocketURL(debugBase, t.WebSocketDebuggerURL)
+			if err != nil {
+				return nil, coreerr.E("CDPClient.New", "invalid target WebSocket URL", err)
+			}
 			break
 		}
 	}
 
 	if wsURL == "" {
-		// Try to create a new target
-		resp, err := http.Get(debugURL + "/json/new")
+		newTarget, err := createTargetAt(ctx, debugBase, "")
 		if err != nil {
 			return nil, coreerr.E("CDPClient.New", "no page targets found and failed to create new", err)
 		}
-		defer func() { _ = resp.Body.Close() }()
 
-		body, err := io.ReadAll(resp.Body)
+		wsURL, err = validateTargetWebSocketURL(debugBase, newTarget.WebSocketDebuggerURL)
 		if err != nil {
-			return nil, coreerr.E("CDPClient.New", "failed to read new target", err)
+			return nil, coreerr.E("CDPClient.New", "invalid new target WebSocket URL", err)
 		}
-
-		var newTarget TargetInfo
-		if err := json.Unmarshal(body, &newTarget); err != nil {
-			return nil, coreerr.E("CDPClient.New", "failed to parse new target", err)
-		}
-
-		wsURL = newTarget.WebSocketDebuggerURL
 	}
 
 	if wsURL == "" {
@@ -133,30 +145,17 @@ func NewCDPClient(debugURL string) (*CDPClient, error) {
 		return nil, coreerr.E("CDPClient.New", "failed to connect to WebSocket", err)
 	}
 
-	ctx, cancel := context.WithCancel(context.Background())
-
-	client := &CDPClient{
-		conn:     conn,
-		debugURL: debugURL,
-		wsURL:    wsURL,
-		pending:  make(map[int64]chan *cdpResponse),
-		handlers: make(map[string][]func(map[string]any)),
-		ctx:      ctx,
-		cancel:   cancel,
-		done:     make(chan struct{}),
-	}
-
-	// Start message reader
-	go client.readLoop()
-
-	return client, nil
+	return newCDPClient(debugBase, wsURL, conn), nil
 }
 
 // Close closes the CDP connection.
 func (c *CDPClient) Close() error {
-	c.cancel()
-	<-c.done // Wait for read loop to finish
-	return c.conn.Close()
+	c.close(errCDPClientClosed)
+	<-c.done
+	if c.closeErr != nil {
+		return coreerr.E("CDPClient.Close", "failed to close WebSocket", c.closeErr)
+	}
+	return nil
 }
 
 // Call sends a CDP method call and waits for the response.
@@ -166,7 +165,7 @@ func (c *CDPClient) Call(ctx context.Context, method string, params map[string]a
 	msg := cdpMessage{
 		ID:     id,
 		Method: method,
-		Params: params,
+		Params: cloneMapAny(params),
 	}
 
 	// Register response channel
@@ -193,6 +192,8 @@ func (c *CDPClient) Call(ctx context.Context, method string, params map[string]a
 	select {
 	case <-ctx.Done():
 		return nil, ctx.Err()
+	case <-c.ctx.Done():
+		return nil, coreerr.E("CDPClient.Call", "client closed", errCDPClientClosed)
 	case resp := <-respCh:
 		if resp.Error != nil {
 			return nil, coreerr.E("CDPClient.Call", resp.Error.Message, nil)
@@ -213,22 +214,23 @@ func (c *CDPClient) readLoop() {
 	defer close(c.done)
 
 	for {
-		select {
-		case <-c.ctx.Done():
-			return
-		default:
-		}
-
 		_, data, err := c.conn.ReadMessage()
 		if err != nil {
-			// Check if context was cancelled
-			select {
-			case <-c.ctx.Done():
+			if c.ctx.Err() != nil {
 				return
-			default:
-				// Log error but continue (could be temporary)
+			}
+			if isTerminalReadError(err) {
+				c.close(err)
+				return
+			}
+
+			var netErr net.Error
+			if errors.As(err, &netErr) && netErr.Timeout() {
 				continue
 			}
+
+			c.close(err)
+			return
 		}
 
 		// Try to parse as response
@@ -237,7 +239,10 @@ func (c *CDPClient) readLoop() {
 			c.pendMu.Lock()
 			if ch, ok := c.pending[resp.ID]; ok {
 				respCopy := resp
-				ch <- &respCopy
+				select {
+				case ch <- &respCopy:
+				default:
+				}
 			}
 			c.pendMu.Unlock()
 			continue
@@ -259,7 +264,8 @@ func (c *CDPClient) dispatchEvent(method string, params map[string]any) {
 
 	for _, handler := range handlers {
 		// Call handler in goroutine to avoid blocking
-		go handler(params)
+		handlerParams := cloneMapAny(params)
+		go handler(handlerParams)
 	}
 }
 
@@ -267,7 +273,7 @@ func (c *CDPClient) dispatchEvent(method string, params map[string]any) {
 func (c *CDPClient) Send(method string, params map[string]any) error {
 	msg := cdpMessage{
 		Method: method,
-		Params: params,
+		Params: cloneMapAny(params),
 	}
 
 	c.mu.Lock()
@@ -287,83 +293,70 @@ func (c *CDPClient) WebSocketURL() string {
 
 // NewTab creates a new browser tab and returns a new CDPClient connected to it.
 func (c *CDPClient) NewTab(url string) (*CDPClient, error) {
-	endpoint := c.debugURL + "/json/new"
-	if url != "" {
-		endpoint += "?" + url
-	}
+	ctx, cancel := context.WithTimeout(c.ctx, debugEndpointTimeout)
+	defer cancel()
 
-	resp, err := http.Get(endpoint)
+	target, err := createTargetAt(ctx, c.debugBase, url)
 	if err != nil {
 		return nil, coreerr.E("CDPClient.NewTab", "failed to create new tab", err)
 	}
-	defer func() { _ = resp.Body.Close() }()
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, coreerr.E("CDPClient.NewTab", "failed to read response", err)
-	}
-
-	var target TargetInfo
-	if err := json.Unmarshal(body, &target); err != nil {
-		return nil, coreerr.E("CDPClient.NewTab", "failed to parse target", err)
-	}
 
 	if target.WebSocketDebuggerURL == "" {
 		return nil, coreerr.E("CDPClient.NewTab", "no WebSocket URL for new tab", nil)
 	}
 
+	wsURL, err := validateTargetWebSocketURL(c.debugBase, target.WebSocketDebuggerURL)
+	if err != nil {
+		return nil, coreerr.E("CDPClient.NewTab", "invalid WebSocket URL for new tab", err)
+	}
+
 	// Connect to new tab
-	conn, _, err := websocket.DefaultDialer.Dial(target.WebSocketDebuggerURL, nil)
+	conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
 	if err != nil {
 		return nil, coreerr.E("CDPClient.NewTab", "failed to connect to new tab", err)
 	}
 
-	ctx, cancel := context.WithCancel(context.Background())
-
-	client := &CDPClient{
-		conn:     conn,
-		debugURL: c.debugURL,
-		wsURL:    target.WebSocketDebuggerURL,
-		pending:  make(map[int64]chan *cdpResponse),
-		handlers: make(map[string][]func(map[string]any)),
-		ctx:      ctx,
-		cancel:   cancel,
-		done:     make(chan struct{}),
-	}
-
-	go client.readLoop()
-
-	return client, nil
+	return newCDPClient(c.debugBase, wsURL, conn), nil
 }
 
 // CloseTab closes the current tab (target).
 func (c *CDPClient) CloseTab() error {
-	// Extract target ID from WebSocket URL
-	// Format: ws://host:port/devtools/page/TARGET_ID
-	// We'll use the Browser.close target API
+	targetID, err := targetIDFromWebSocketURL(c.wsURL)
+	if err != nil {
+		return coreerr.E("CDPClient.CloseTab", "failed to determine target ID", err)
+	}
 
-	ctx := context.Background()
-	_, err := c.Call(ctx, "Browser.close", nil)
-	return err
+	ctx, cancel := context.WithTimeout(c.ctx, debugEndpointTimeout)
+	defer cancel()
+
+	result, err := c.Call(ctx, "Target.closeTarget", map[string]any{
+		"targetId": targetID,
+	})
+	if err != nil {
+		return coreerr.E("CDPClient.CloseTab", "failed to close target", err)
+	}
+
+	if success, ok := result["success"].(bool); ok && !success {
+		return coreerr.E("CDPClient.CloseTab", "target close was not acknowledged", nil)
+	}
+
+	return c.Close()
 }
 
 // ListTargets returns all available targets.
 func ListTargets(debugURL string) ([]TargetInfo, error) {
-	resp, err := http.Get(debugURL + "/json")
+	debugBase, err := parseDebugURL(debugURL)
+	if err != nil {
+		return nil, coreerr.E("ListTargets", "invalid debug URL", err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), debugEndpointTimeout)
+	defer cancel()
+
+	targets, err := listTargetsAt(ctx, debugBase)
 	if err != nil {
 		return nil, coreerr.E("ListTargets", "failed to get targets", err)
 	}
-	defer func() { _ = resp.Body.Close() }()
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, coreerr.E("ListTargets", "failed to read targets", err)
-	}
-
-	var targets []TargetInfo
-	if err := json.Unmarshal(body, &targets); err != nil {
-		return nil, coreerr.E("ListTargets", "failed to parse targets", err)
-	}
 
 	return targets, nil
 }
@@ -385,16 +378,18 @@ func ListTargetsAll(debugURL string) iter.Seq[TargetInfo] {
 
 // GetVersion returns Chrome version information.
 func GetVersion(debugURL string) (map[string]string, error) {
-	resp, err := http.Get(debugURL + "/json/version")
+	debugBase, err := parseDebugURL(debugURL)
+	if err != nil {
+		return nil, coreerr.E("GetVersion", "invalid debug URL", err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), debugEndpointTimeout)
+	defer cancel()
+
+	body, err := doDebugRequest(ctx, debugBase, "/json/version", "")
 	if err != nil {
 		return nil, coreerr.E("GetVersion", "failed to get version", err)
 	}
-	defer func() { _ = resp.Body.Close() }()
-
-	body, err := io.ReadAll(resp.Body)
-	if err != nil {
-		return nil, coreerr.E("GetVersion", "failed to read version", err)
-	}
 
 	var version map[string]string
 	if err := json.Unmarshal(body, &version); err != nil {
@@ -403,3 +398,241 @@ func GetVersion(debugURL string) (map[string]string, error) {
 
 	return version, nil
 }
+
+func newCDPClient(debugBase *url.URL, wsURL string, conn *websocket.Conn) *CDPClient {
+	ctx, cancel := context.WithCancel(context.Background())
+	baseCopy := *debugBase
+
+	client := &CDPClient{
+		conn:      conn,
+		debugURL:  canonicalDebugURL(&baseCopy),
+		debugBase: &baseCopy,
+		wsURL:     wsURL,
+		pending:   make(map[int64]chan *cdpResponse),
+		handlers:  make(map[string][]func(map[string]any)),
+		ctx:       ctx,
+		cancel:    cancel,
+		done:      make(chan struct{}),
+	}
+
+	go client.readLoop()
+
+	return client
+}
+
+func parseDebugURL(raw string) (*url.URL, error) {
+	debugURL, err := url.Parse(raw)
+	if err != nil {
+		return nil, err
+	}
+	if debugURL.Scheme != "http" && debugURL.Scheme != "https" {
+		return nil, coreerr.E("CDPClient.parseDebugURL", "debug URL must use http or https", nil)
+	}
+	if debugURL.Host == "" {
+		return nil, coreerr.E("CDPClient.parseDebugURL", "debug URL host is required", nil)
+	}
+	if debugURL.User != nil {
+		return nil, coreerr.E("CDPClient.parseDebugURL", "debug URL must not include credentials", nil)
+	}
+	if debugURL.RawQuery != "" || debugURL.Fragment != "" {
+		return nil, coreerr.E("CDPClient.parseDebugURL", "debug URL must not include query or fragment", nil)
+	}
+	if debugURL.Path == "" {
+		debugURL.Path = "/"
+	}
+	if debugURL.Path != "/" {
+		return nil, coreerr.E("CDPClient.parseDebugURL", "debug URL must point at the DevTools root", nil)
+	}
+	return debugURL, nil
+}
+
+func canonicalDebugURL(debugURL *url.URL) string {
+	return strings.TrimSuffix(debugURL.String(), "/")
+}
+
+func doDebugRequest(ctx context.Context, debugBase *url.URL, endpoint, rawQuery string) ([]byte, error) {
+	reqURL := *debugBase
+	reqURL.Path = endpoint
+	reqURL.RawPath = ""
+	reqURL.RawQuery = rawQuery
+	reqURL.Fragment = ""
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, reqURL.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := defaultDebugHTTPClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
+		return nil, coreerr.E("CDPClient.doDebugRequest", "debug endpoint returned "+resp.Status, nil)
+	}
+
+	return body, nil
+}
+
+func listTargetsAt(ctx context.Context, debugBase *url.URL) ([]TargetInfo, error) {
+	body, err := doDebugRequest(ctx, debugBase, "/json", "")
+	if err != nil {
+		return nil, err
+	}
+
+	var targets []TargetInfo
+	if err := json.Unmarshal(body, &targets); err != nil {
+		return nil, err
+	}
+
+	return targets, nil
+}
+
+func createTargetAt(ctx context.Context, debugBase *url.URL, pageURL string) (*TargetInfo, error) {
+	rawQuery := ""
+	if pageURL != "" {
+		rawQuery = url.QueryEscape(pageURL)
+	}
+
+	body, err := doDebugRequest(ctx, debugBase, "/json/new", rawQuery)
+	if err != nil {
+		return nil, err
+	}
+
+	var target TargetInfo
+	if err := json.Unmarshal(body, &target); err != nil {
+		return nil, err
+	}
+
+	return &target, nil
+}
+
+func validateTargetWebSocketURL(debugBase *url.URL, raw string) (string, error) {
+	wsURL, err := url.Parse(raw)
+	if err != nil {
+		return "", err
+	}
+	if wsURL.Scheme != "ws" && wsURL.Scheme != "wss" {
+		return "", coreerr.E("CDPClient.validateTargetWebSocketURL", "target WebSocket URL must use ws or wss", nil)
+	}
+	if !sameEndpointHost(debugBase, wsURL) {
+		return "", coreerr.E("CDPClient.validateTargetWebSocketURL", "target WebSocket URL must match debug URL host", nil)
+	}
+	return wsURL.String(), nil
+}
+
+func sameEndpointHost(httpURL, wsURL *url.URL) bool {
+	return strings.EqualFold(httpURL.Hostname(), wsURL.Hostname()) && normalisedPort(httpURL) == normalisedPort(wsURL)
+}
+
+func normalisedPort(u *url.URL) string {
+	if port := u.Port(); port != "" {
+		return port
+	}
+
+	switch u.Scheme {
+	case "http", "ws":
+		return "80"
+	case "https", "wss":
+		return "443"
+	default:
+		return ""
+	}
+}
+
+func targetIDFromWebSocketURL(raw string) (string, error) {
+	wsURL, err := url.Parse(raw)
+	if err != nil {
+		return "", err
+	}
+
+	targetID := path.Base(strings.TrimSuffix(wsURL.Path, "/"))
+	if targetID == "." || targetID == "/" || targetID == "" {
+		return "", coreerr.E("CDPClient.targetIDFromWebSocketURL", "missing target ID in WebSocket URL", nil)
+	}
+
+	return targetID, nil
+}
+
+func (c *CDPClient) close(reason error) {
+	c.closeOnce.Do(func() {
+		c.cancel()
+		c.failPending(reason)
+
+		c.mu.Lock()
+		err := c.conn.Close()
+		c.mu.Unlock()
+		if err != nil && !isTerminalReadError(err) {
+			c.closeErr = err
+		}
+	})
+}
+
+func (c *CDPClient) failPending(err error) {
+	c.pendMu.Lock()
+	defer c.pendMu.Unlock()
+
+	for id, ch := range c.pending {
+		resp := &cdpResponse{
+			ID: id,
+			Error: &cdpError{
+				Message: err.Error(),
+			},
+		}
+		select {
+		case ch <- resp:
+		default:
+		}
+	}
+}
+
+func isTerminalReadError(err error) bool {
+	if err == nil {
+		return false
+	}
+	if errors.Is(err, net.ErrClosed) || errors.Is(err, websocket.ErrCloseSent) {
+		return true
+	}
+	var closeErr *websocket.CloseError
+	return errors.As(err, &closeErr)
+}
+
+func cloneMapAny(src map[string]any) map[string]any {
+	if src == nil {
+		return nil
+	}
+
+	dst := make(map[string]any, len(src))
+	for key, value := range src {
+		dst[key] = cloneAny(value)
+	}
+	return dst
+}
+
+func cloneSliceAny(src []any) []any {
+	if src == nil {
+		return nil
+	}
+
+	dst := make([]any, len(src))
+	for i, value := range src {
+		dst[i] = cloneAny(value)
+	}
+	return dst
+}
+
+func cloneAny(value any) any {
+	switch typed := value.(type) {
+	case map[string]any:
+		return cloneMapAny(typed)
+	case []any:
+		return cloneSliceAny(typed)
+	default:
+		return typed
+	}
+}

console.go

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: EUPL-1.2
 package webview
 
 import (
@@ -7,17 +8,19 @@ import (
 	"slices"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 )
 
 // ConsoleWatcher provides advanced console message watching capabilities.
 type ConsoleWatcher struct {
-	mu       sync.RWMutex
-	wv       *Webview
-	messages []ConsoleMessage
-	filters  []ConsoleFilter
-	limit    int
-	handlers []ConsoleHandler
+	mu            sync.RWMutex
+	wv            *Webview
+	messages      []ConsoleMessage
+	filters       []ConsoleFilter
+	limit         int
+	handlers      []consoleHandlerRegistration
+	nextHandlerID atomic.Int64
 }
 
 // ConsoleFilter filters console messages.
@@ -29,6 +32,11 @@ type ConsoleFilter struct {
 // ConsoleHandler is called when a matching console message is received.
 type ConsoleHandler func(msg ConsoleMessage)
 
+type consoleHandlerRegistration struct {
+	id      int64
+	handler ConsoleHandler
+}
+
 // NewConsoleWatcher creates a new console watcher for the webview.
 func NewConsoleWatcher(wv *Webview) *ConsoleWatcher {
 	cw := &ConsoleWatcher{
@@ -36,7 +44,7 @@ func NewConsoleWatcher(wv *Webview) *ConsoleWatcher {
 		messages: make([]ConsoleMessage, 0, 100),
 		filters:  make([]ConsoleFilter, 0),
 		limit:    1000,
-		handlers: make([]ConsoleHandler, 0),
+		handlers: make([]consoleHandlerRegistration, 0),
 	}
 
 	// Subscribe to console events from the webview's client
@@ -63,9 +71,30 @@ func (cw *ConsoleWatcher) ClearFilters() {
 
 // AddHandler adds a handler for console messages.
 func (cw *ConsoleWatcher) AddHandler(handler ConsoleHandler) {
+	cw.addHandler(handler)
+}
+
+func (cw *ConsoleWatcher) addHandler(handler ConsoleHandler) int64 {
 	cw.mu.Lock()
 	defer cw.mu.Unlock()
-	cw.handlers = append(cw.handlers, handler)
+	id := cw.nextHandlerID.Add(1)
+	cw.handlers = append(cw.handlers, consoleHandlerRegistration{
+		id:      id,
+		handler: handler,
+	})
+	return id
+}
+
+func (cw *ConsoleWatcher) removeHandler(id int64) {
+	cw.mu.Lock()
+	defer cw.mu.Unlock()
+
+	for i, registration := range cw.handlers {
+		if registration.id == id {
+			cw.handlers = slices.Delete(cw.handlers, i, i+1)
+			return
+		}
+	}
 }
 
 // SetLimit sets the maximum number of messages to retain.
@@ -187,13 +216,8 @@ func (cw *ConsoleWatcher) WaitForMessage(ctx context.Context, filter ConsoleFilt
 		}
 	}
 
-	cw.AddHandler(handler)
-	defer func() {
-		cw.mu.Lock()
-		// Remove handler (simple implementation - in production you'd want a handle-based removal)
-		cw.handlers = cw.handlers[:len(cw.handlers)-1]
-		cw.mu.Unlock()
-	}()
+	handlerID := cw.addHandler(handler)
+	defer cw.removeHandler(handlerID)
 
 	select {
 	case <-ctx.Done():
@@ -302,8 +326,8 @@ func (cw *ConsoleWatcher) addMessage(msg ConsoleMessage) {
 	cw.mu.Unlock()
 
 	// Call handlers
-	for _, handler := range handlers {
-		handler(msg)
+	for _, registration := range handlers {
+		registration.handler(msg)
 	}
 }
 
@@ -361,10 +385,16 @@ type ExceptionInfo struct {
 
 // ExceptionWatcher watches for JavaScript exceptions.
 type ExceptionWatcher struct {
-	mu         sync.RWMutex
-	wv         *Webview
-	exceptions []ExceptionInfo
-	handlers   []func(ExceptionInfo)
+	mu            sync.RWMutex
+	wv            *Webview
+	exceptions    []ExceptionInfo
+	handlers      []exceptionHandlerRegistration
+	nextHandlerID atomic.Int64
+}
+
+type exceptionHandlerRegistration struct {
+	id      int64
+	handler func(ExceptionInfo)
 }
 
 // NewExceptionWatcher creates a new exception watcher.
@@ -372,7 +402,7 @@ func NewExceptionWatcher(wv *Webview) *ExceptionWatcher {
 	ew := &ExceptionWatcher{
 		wv:         wv,
 		exceptions: make([]ExceptionInfo, 0),
-		handlers:   make([]func(ExceptionInfo), 0),
+		handlers:   make([]exceptionHandlerRegistration, 0),
 	}
 
 	// Subscribe to exception events
@@ -425,9 +455,30 @@ func (ew *ExceptionWatcher) Count() int {
 
 // AddHandler adds a handler for exceptions.
 func (ew *ExceptionWatcher) AddHandler(handler func(ExceptionInfo)) {
+	ew.addHandler(handler)
+}
+
+func (ew *ExceptionWatcher) addHandler(handler func(ExceptionInfo)) int64 {
 	ew.mu.Lock()
 	defer ew.mu.Unlock()
-	ew.handlers = append(ew.handlers, handler)
+	id := ew.nextHandlerID.Add(1)
+	ew.handlers = append(ew.handlers, exceptionHandlerRegistration{
+		id:      id,
+		handler: handler,
+	})
+	return id
+}
+
+func (ew *ExceptionWatcher) removeHandler(id int64) {
+	ew.mu.Lock()
+	defer ew.mu.Unlock()
+
+	for i, registration := range ew.handlers {
+		if registration.id == id {
+			ew.handlers = slices.Delete(ew.handlers, i, i+1)
+			return
+		}
+	}
 }
 
 // WaitForException waits for an exception to be thrown.
@@ -450,12 +501,8 @@ func (ew *ExceptionWatcher) WaitForException(ctx context.Context) (*ExceptionInf
 		}
 	}
 
-	ew.AddHandler(handler)
-	defer func() {
-		ew.mu.Lock()
-		ew.handlers = ew.handlers[:len(ew.handlers)-1]
-		ew.mu.Unlock()
-	}()
+	handlerID := ew.addHandler(handler)
+	defer ew.removeHandler(handlerID)
 
 	select {
 	case <-ctx.Done():
@@ -515,8 +562,8 @@ func (ew *ExceptionWatcher) handleException(params map[string]any) {
 	ew.mu.Unlock()
 
 	// Call handlers
-	for _, handler := range handlers {
-		handler(info)
+	for _, registration := range handlers {
+		registration.handler(info)
 	}
 }
 

webview.go

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: EUPL-1.2
 // Package webview provides browser automation via Chrome DevTools Protocol (CDP).
 //
 // The package allows controlling Chrome/Chromium browsers for automated testing,
@@ -118,9 +119,16 @@ func New(opts ...Option) (*Webview, error) {
 		consoleLimit: 1000,
 	}
 
+	cleanupOnError := func() {
+		cancel()
+		if wv.client != nil {
+			_ = wv.client.Close()
+		}
+	}
+
 	for _, opt := range opts {
 		if err := opt(wv); err != nil {
-			cancel()
+			cleanupOnError()
 			return nil, err
 		}
 	}
@@ -132,7 +140,7 @@ func New(opts ...Option) (*Webview, error) {
 
 	// Enable console capture
 	if err := wv.enableConsole(); err != nil {
-		cancel()
+		cleanupOnError()
 		return nil, coreerr.E("Webview.New", "failed to enable console capture", err)
 	}
 
@@ -542,6 +550,7 @@ func (wv *Webview) evaluate(ctx context.Context, script string) (any, error) {
 	result, err := wv.client.Call(ctx, "Runtime.evaluate", map[string]any{
 		"expression":    script,
 		"returnByValue": true,
+		"awaitPromise":  true,
 	})
 	if err != nil {
 		return nil, coreerr.E("Webview.evaluate", "failed to evaluate script", err)

webview_test.go

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: EUPL-1.2
 package webview
 
 import (
@@ -427,6 +428,8 @@ func TestFormatJSValue_Good(t *testing.T) {
 		{nil, "null"},
 		{42, "42"},
 		{3.14, "3.14"},
+		{map[string]any{"enabled": true}, `{"enabled":true}`},
+		{[]any{1, "two"}, `[1,"two"]`},
 	}
 
 	for _, tc := range tests {
@@ -512,7 +515,7 @@ func TestConsoleWatcherFilter_Good(t *testing.T) {
 		messages: make([]ConsoleMessage, 0),
 		filters:  make([]ConsoleFilter, 0),
 		limit:    1000,
-		handlers: make([]ConsoleHandler, 0),
+		handlers: make([]consoleHandlerRegistration, 0),
 	}
 
 	// No filters — everything matches
@@ -556,7 +559,7 @@ func TestConsoleWatcherCounts_Good(t *testing.T) {
 		},
 		filters:  make([]ConsoleFilter, 0),
 		limit:    1000,
-		handlers: make([]ConsoleHandler, 0),
+		handlers: make([]consoleHandlerRegistration, 0),
 	}
 
 	if cw.Count() != 5 {
@@ -592,7 +595,7 @@ func TestConsoleWatcherCounts_Good(t *testing.T) {
 func TestExceptionWatcher_Good(t *testing.T) {
 	ew := &ExceptionWatcher{
 		exceptions: make([]ExceptionInfo, 0),
-		handlers:   make([]func(ExceptionInfo), 0),
+		handlers:   make([]exceptionHandlerRegistration, 0),
 	}
 
 	if ew.HasExceptions() {
@@ -682,7 +685,7 @@ func TestConsoleWatcherAddMessage_Good(t *testing.T) {
 		messages: make([]ConsoleMessage, 0),
 		filters:  make([]ConsoleFilter, 0),
 		limit:    5,
-		handlers: make([]ConsoleHandler, 0),
+		handlers: make([]consoleHandlerRegistration, 0),
 	}
 
 	// Add messages past the limit
@@ -704,7 +707,7 @@ func TestConsoleWatcherHandler_Good(t *testing.T) {
 		messages: make([]ConsoleMessage, 0),
 		filters:  make([]ConsoleFilter, 0),
 		limit:    1000,
-		handlers: make([]ConsoleHandler, 0),
+		handlers: make([]consoleHandlerRegistration, 0),
 	}
 
 	var received ConsoleMessage
@@ -729,7 +732,7 @@ func TestConsoleWatcherFilteredMessages_Good(t *testing.T) {
 		},
 		filters:  []ConsoleFilter{{Type: "error"}},
 		limit:    1000,
-		handlers: make([]ConsoleHandler, 0),
+		handlers: make([]consoleHandlerRegistration, 0),
 	}
 
 	filtered := cw.FilteredMessages()