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DEMRUM-2370: webview injection fix including legacy support #328

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3c89ed0
DEMRUM-2370: implement user script approach
carlosmcevilly Jun 7, 2025
a484d83
DEMRUM-2370: Implement hybrid sync/async solution for partial legacy …
carlosmcevilly Jun 10, 2025
dbb3874
Merge branch 'feature/next-gen' into bugfix/DEMRUM-2370-webview-injec…
carlosmcevilly Jun 10, 2025
bc797a8
DEMRUM: 2370: address lint issue: consistent order of modifiers
carlosmcevilly Jun 10, 2025
9110caa
DEMRUM-2370: resolve some lint errors
carlosmcevilly Jun 10, 2025
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153 changes: 102 additions & 51 deletions Applications/DevelApp/DevelApp/WebViewDemoView.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -22,83 +22,133 @@ import SwiftUI
import WebKit

struct WebViewDemoView: View {
@State private var webView = WKWebView()
@State private var injected = false
@State private var subscription: AnyCancellable?
@State private var modernWebView = WKWebView()
@State private var legacyWebView = WKWebView()

// Store the script content in variables
private let modernScriptContent = modernScriptExample()
private let legacyScriptContent = legacyScriptExample()

var body: some View {
VStack {
Text("WebView Demo").font(.title).padding()
DemoHeaderView()
WebViewRepresentable(webView: webView, injected: injected)
.frame(height: 200)
.border(Color.gray)
.padding()

Button("Inject JavaScript") {
injectJavaScript()
}
.padding()
// Legacy WebView Section
WebViewSectionView(
caption: "WebView using current BRUM legacy API",
webView: legacyWebView,
buttonText: "Inject JavaScript (legacy, sync)",
backgroundColor: Color(red: 0.9, green: 0.93, blue: 1.0),
scriptContent: legacyScriptContent,
injectAction: injectIntoLegacyWebView
)

// Modern WebView Section
WebViewSectionView(
caption: "WebView using future BRUM async API",
webView: modernWebView,
buttonText: "Inject JavaScript (modern, async)",
backgroundColor: Color(red: 0.88, green: 1.0, blue: 0.88),
scriptContent: modernScriptContent,
injectAction: injectIntoModernWebView
)

Spacer()
}
.onAppear {
loadWebViewContent()
observeSessionIdChanges()
}
.onDisappear {
subscription?.cancel()
loadWebViewContent(for: modernWebView, scriptContent: modernScriptContent)
loadWebViewContent(for: legacyWebView, scriptContent: legacyScriptContent)
}
.navigationTitle("WebView Demo")
}

private func loadWebViewContent() {
// Load a simple HTML page with a placeholder for the session ID
private static func modernScriptExample() -> String {
return """
async function updateSessionId() {
try {
const response = await window.SplunkRumNative.getNativeSessionIdAsync();
document.getElementById('sessionId').innerText = response;
} catch (error) {
document.getElementById('sessionId').innerText = "unknown";
console.log(`Error getting native Session ID: ${error.message}`);
}
}
setInterval(updateSessionId, 1000);
"""
}

private static func legacyScriptExample() -> String {
return """
function updateSessionId() {
try {
const sessionId = window.SplunkRumNative.getNativeSessionId();
document.getElementById('sessionId').innerText = sessionId;
} catch (error) {
document.getElementById('sessionId').innerText = "unknown";
console.log(`Error getting native Session ID: ${error.message}`);
}
}
setInterval(updateSessionId, 1000);
"""
}

private func loadWebViewContent(for webView: WKWebView, scriptContent: String) {
let initialContent = """
<!DOCTYPE html>
<html>
<head>
<title>WebView Demo</title>
<script>
function updateSessionId() {
// Fetch the session ID from the native layer
const sessionId = window.SplunkRumNative.getNativeSessionId();
document.getElementById('sessionId').innerText = sessionId;
}

// Update the session ID every 1 second
setInterval(updateSessionId, 1000);
</script>
</head>
<body>
<h1>WebView Demo</h1>
<p>Current Session ID:</p>
<p id="sessionId">unknown</p>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<script>
\(scriptContent)
</script>
</head>
<body style="font-size: 48px; font-family: sans-serif">
<h3>Current Native Session ID:</h3>
<p id="sessionId">unknown</p>
</body>
</html>
"""
webView.loadHTMLString(initialContent, baseURL: nil)
}

private func injectJavaScript() {
// This integrates the web view with SplunkRum
SplunkRum.webView.integrateWithBrowserRum(webView)
injected = true
private func injectIntoModernWebView() {
SplunkRum.webView.integrateWithBrowserRum(modernWebView)
}

private func injectIntoLegacyWebView() {
SplunkRum.webView.integrateWithBrowserRum(legacyWebView)
}
}

struct WebViewSectionView: View {
let caption: String
let webView: WKWebView
let buttonText: String
let backgroundColor: Color
let scriptContent: String
let injectAction: () -> Void

private func observeSessionIdChanges() {
// Observe changes to the session ID and reload the web view content if needed
subscription = NotificationCenter.default
.publisher(for: NSNotification.Name("com.splunk.rum.session-id-did-change"))
.sink { _ in
print("Session ID changed. WebView should now reflect the updated value.")
var body: some View {
VStack {
Text(caption)
.font(.footnote)
.padding(.top)
WebViewRepresentable(webView: webView)
.frame(height: 150)
.border(Color.gray)
.padding(.horizontal)
Button(buttonText) {
injectAction()
}
.padding()
}
.background(backgroundColor)
.cornerRadius(8)
.padding()
}
}

struct WebViewRepresentable: UIViewRepresentable {
let webView: WKWebView
let injected: Bool

func makeUIView(context: Context) -> WKWebView {
return webView
Expand All @@ -108,3 +158,4 @@ struct WebViewRepresentable: UIViewRepresentable {
// Nothing to do here
}
}

151 changes: 122 additions & 29 deletions SplunkWebView/Sources/SplunkWebView/WebViewInstrumentationInternal.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ internal import CiscoLogger
import SplunkCommon
import WebKit

public final class WebViewInstrumentationInternal {
public final class WebViewInstrumentationInternal: NSObject {

public static var instance = WebViewInstrumentationInternal()

Expand All @@ -28,47 +28,140 @@ public final class WebViewInstrumentationInternal {
public var sharedState: AgentSharedState?

// Module conformance
public required init() {}
public required override init() {}

// MARK: - Internal Methods

// swiftlint:disable function_body_length
public func injectSessionId(into webView: WKWebView) {

guard let sessionId = sharedState?.sessionId else {
logger.log(level: .warn) {
"Session ID not available."
"Native Session ID not available for webview injection."
}
return
}

// Extracted JavaScript template for better readability and maintainability
let script = """
if (!window.SplunkRumNative) {
window.SplunkRumNative = {
cachedSessionId: '\(sessionId)',
getNativeSessionId: function() {
try {
window.webkit.messageHandlers.SplunkRumNativeUpdate.postMessage('').catch(function() {});
} catch (e) {
console.error('Error in getNativeSessionId:', e); // Improved error handling
}
return window.SplunkRumNative.cachedSessionId;
},
};
let javaScript = """
if (window.SplunkRumNative && window.SplunkRumNative._isInitialized) {
console.log("[SplunkRumNative] Already initialized; skipping.");
} else {
window.SplunkRumNative.cachedSessionId = '\(sessionId)';
}
window.SplunkRumNative = (function() {
const debounceDurationMs = 1000;
const staleAfterDurationMs = 5000;
const self = {
cachedSessionId: '\(sessionId)',
_isInitialized: false,
_lastCheckTime: Date.now(),
_updateInProgress: false,
onNativeSessionIdChanged: null,

_fetchSessionId: function() {
return window.webkit.messageHandlers.SplunkRumNativeUpdate
.postMessage({})
.then((r) => r.sessionId)
.catch( function(error) {
console.error("[SplunkRumNative] Failed to fetch native session ID:", error);
throw error;
});
},
_notifyChange: function(oldId, newId) {
if (typeof self.onNativeSessionIdChanged === "function") {
try {
self.onNativeSessionIdChanged({
currentId: newId,
previousId: oldId,
timestamp: Date.now()
});
} catch (error) {
console.error("[SplunkRumNative] Error in application-provided callback for onNativeSessionIdChanged:", error);
}
}
},
// This must be synchronous for legacy BRUM compatibility.
getNativeSessionId: function() {
const now = Date.now();
const stale = (now - self._lastCheckTime) > staleAfterDurationMs;
if (stale && !self._updateInProgress) {
self._updateInProgress = true;
self._lastCheckTime = now;
self._fetchSessionId()
.then( function(newId) {
if (newId !== self.cachedSessionId) {
const oldId = self.cachedSessionId;
self.cachedSessionId = newId;
self._notifyChange(oldId, newId);
}
})
.catch( function(error) {
console.error("[SplunkRumNative] Failed to fetch session ID from native:", error);
})
.finally( function() {
self._updateInProgress = false;
});
}
// Here we finish before above promise is fulfilled, and
// return cached ID immediately for legacy compatibility.
return self.cachedSessionId;
},
// Recommended for BRUM use in new agents going forward.
getNativeSessionIdAsync: async function() {
const newId = await self._fetchSessionId();
if (newId !== self.cachedSessionId) {
const oldId = self.cachedSessionId;
self.cachedSessionId = newId;
self._notifyChange(oldId, newId);
}
return newId;
}
};
console.log("[SplunkRumNative] Initialized with native session:", self.cachedSessionId)
console.log("[SplunkRumNative] Bridge available:", Boolean(window.webkit?.messageHandlers?.SplunkRumNativeUpdate));
return self;
}());
}
"""

webView.evaluateJavaScript(script) { _, error in
if let error = error {
self.logger.log(level: .error) {
"Error injecting JavaScript: \(error)"
}
} else {
self.logger.log(level: .debug) {
"JavaScript injected successfully."
}
}
let userScript = WKUserScript(
source: javaScript,
injectionTime: .atDocumentStart, // expected by legacy BRUM
forMainFrameOnly: false // expected by legacy BRUM
)

contentController(
forName: "SplunkRumNativeUpdate",
forWebView: webView
).addUserScript(userScript)

// Needed at first load only; user script will persist across reloads and navigation
webView.evaluateJavaScript(javaScript)
}

// swiftlint:enable function_body_length

private func contentController(forName name: String, forWebView webView: WKWebView) -> WKUserContentController {
let contentController = webView.configuration.userContentController
contentController.removeScriptMessageHandler(forName: name)
contentController.addScriptMessageHandler(self, contentWorld: .page, name: name)
return contentController
}
}

// MARK: - WKScriptMessageHandlerWithReply

extension WebViewInstrumentationInternal: WKScriptMessageHandlerWithReply {

/// Handles JavaScript messages with a reply handler for asynchronous communication
public func userContentController(
_ userContentController: WKUserContentController,
didReceive message: WKScriptMessage,
replyHandler: @escaping @MainActor @Sendable (Any?, String?) -> Void
) {
// hint: parse message.body["action"] here if you need to add features
if let sessionId = sharedState?.sessionId {
replyHandler(["sessionId": sessionId], nil)
} else {
replyHandler(nil, "Native Session ID not available")
}
}
}
Expand Down
1 change: 0 additions & 1 deletion SplunkWebView/Tests/SplunkWebViewTests/WebViewInstrumentationInternalTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,6 @@ final class WebViewInstrumentationInternalTests: XCTestCase {
// Assert that the script is the expected script
XCTAssertTrue(script.contains("window.SplunkRumNative"))
XCTAssertTrue(script.contains("getNativeSessionId"))
XCTAssertTrue(script.contains("cachedSessionId"))
expectation.fulfill()
completionHandler(nil, nil) // Simulate success
}
Expand Down