work in progress changes to migrate onto checkout sheet protocol

.gitignore

@@ -7,4 +7,3 @@ xcuserdata
 .vscode/settings.json
 .claude/
 CLAUDE.md
-

Sources/ShopifyCheckoutSheetKit/CheckoutBridge.swift

@@ -34,30 +34,19 @@ protocol CheckoutBridgeProtocol {
 }
 
 enum CheckoutBridge: CheckoutBridgeProtocol {
-	static let schemaVersion = "8.1"
-	static let messageHandler = "mobileCheckoutSdk"
-	internal static let userAgent = "ShopifyCheckoutSDK/\(ShopifyCheckoutSheetKit.version)"
+	static let schemaVersion = "2025-04"
+	static let messageHandler = "CheckoutSheetProtocolConsumer"
 
 	static var applicationName: String {
-		let theme = ShopifyCheckoutSheetKit.configuration.colorScheme.rawValue
-		let userAgentString = "\(userAgent) (\(schemaVersion);\(theme);standard)"
-
-		return userAgentWithOptionalSuffix(userAgentString)
+		let platform = ShopifyCheckoutSheetKit.configuration.platform?.rawValue ?? "iOS"
+		let userAgentString = "CheckoutKit/\(ShopifyCheckoutSheetKit.version) (\(platform)) CheckoutSheetProtocol/\(schemaVersion)"
+		return userAgentString
 	}
 
 	static var recoveryAgent: String {
-		let theme = ShopifyCheckoutSheetKit.configuration.colorScheme.rawValue
-		let userAgentString = "\(userAgent) (noconnect;\(theme);standard_recovery)"
-
-		return userAgentWithOptionalSuffix(userAgentString)
-	}
-
-	static func userAgentWithOptionalSuffix(_ userAgentString: String) -> String {
-		if let platform = ShopifyCheckoutSheetKit.configuration.platform?.rawValue {
-			return "\(userAgentString) \(platform)"
-		} else {
-			return userAgentString
-		}
+		let platform = ShopifyCheckoutSheetKit.configuration.platform?.rawValue ?? "iOS"
+		let userAgentString = "CheckoutKit/\(ShopifyCheckoutSheetKit.version) (\(platform)) CheckoutSheetProtocol/noconnect"
+		return userAgentString
 	}
 
 	static func instrument(_ webView: WKWebView, _ instrumentation: InstrumentationPayload) {
@@ -91,11 +80,11 @@ enum CheckoutBridge: CheckoutBridgeProtocol {
 
 	static internal func dispatchMessageTemplate(body: String) -> String {
 		return """
-		if (window.MobileCheckoutSdk && window.MobileCheckoutSdk.dispatchMessage) {
-			window.MobileCheckoutSdk.dispatchMessage(\(body));
+		if (window.Shopify?.CheckoutSheetProtocol?.postMessage) {
+			window.Shopify.CheckoutSheetProtocol.postMessage(\(body));
 		} else {
 			window.addEventListener('mobileCheckoutBridgeReady', function () {
-				window.MobileCheckoutSdk.dispatchMessage(\(body));
+				window.Shopify.CheckoutSheetProtocol.postMessage(\(body));
 			}, {passive: true, once: true});
 		}
 		"""

Sources/ShopifyCheckoutSheetKit/CheckoutURL.swift

@@ -59,4 +59,12 @@ public struct CheckoutURL {
 
 		return !["http", "https"].contains(scheme)
 	}
+
+	public func isWebLink() -> Bool {
+		guard let scheme = url.scheme else {
+			return false
+		}
+
+		return ["http", "https"].contains(scheme)
+	}
 }

Sources/ShopifyCheckoutSheetKit/CheckoutWebView.swift

@@ -228,7 +228,12 @@ class CheckoutWebView: WKWebView {
 
 		if isPreload && isPreloadingAvailable {
 			isPreloadRequest = true
-			request.setValue("prefetch", forHTTPHeaderField: "Sec-Purpose")
+		}
+
+		// Add checkout kit headers
+		let headers = checkoutKitHeaders(isPreload: isPreload)
+		for (key, value) in headers {
+			request.setValue(value, forHTTPHeaderField: key)
 		}
 
 		load(request)
@@ -305,6 +310,39 @@ extension CheckoutWebView: WKNavigationDelegate {
 			return
 		}
 
+		// Check if we need to inject headers for main frame navigation
+		if action.targetFrame?.isMainFrame == true && CheckoutURL(from: url).isWebLink() {
+			let currentHeaders = action.request.allHTTPHeaderFields ?? [:]
+			let checkoutHeaders = checkoutKitHeaders()
+			var shouldOverride = false
+			var newHeaders = currentHeaders
+
+			let colorScheme = ShopifyCheckoutSheetKit.configuration.colorScheme
+			let shouldHaveColorSchemeHeader = !(colorScheme == .web || colorScheme == .automatic)
+
+			if shouldHaveColorSchemeHeader && !currentHeaders.hasColorSchemeHeader() {
+				let headersWithColorScheme = currentHeaders.withColorScheme()
+				newHeaders.merge(headersWithColorScheme) { _, new in new }
+				shouldOverride = true
+			}
+
+			if !currentHeaders.hasBrandingHeader() {
+				let headersWithBranding = currentHeaders.withBranding()
+				newHeaders.merge(headersWithBranding) { _, new in new }
+				shouldOverride = true
+			}
+
+			if shouldOverride {
+				var request = URLRequest(url: url)
+				for (key, value) in newHeaders {
+					request.setValue(value, forHTTPHeaderField: key)
+				}
+				webView.load(request)
+				decisionHandler(.cancel)
+				return
+			}
+		}
+
 		decisionHandler(.allow)
 	}
 

Sources/ShopifyCheckoutSheetKit/Headers.swift

@@ -0,0 +1,93 @@
+/*
+MIT License
+
+Copyright 2023 - Present, Shopify Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+import Foundation
+
+internal struct Headers {
+	static let purpose = "Sec-Purpose"
+	static let purposePrefetch = "prefetch"
+
+	static let prefersColorScheme = "Sec-CH-Prefers-Color-Scheme"
+
+	static let branding = "X-Shopify-Checkout-Kit-Branding"
+	static let brandingCheckoutKit = "CHECKOUT_KIT"
+	static let brandingWeb = "WEB_DEFAULT"
+}
+
+internal func checkoutKitHeaders(isPreload: Bool = false) -> [String: String] {
+	var headers = [String: String]()
+
+	if isPreload {
+		headers[Headers.purpose] = Headers.purposePrefetch
+	}
+
+	return headers
+		.withColorScheme()
+		.withBranding()
+}
+
+internal extension Dictionary where Key == String, Value == String {
+	func withColorScheme() -> [String: String] {
+		var headers = self
+
+		let colorScheme = ShopifyCheckoutSheetKit.configuration.colorScheme
+		switch colorScheme {
+		case .light:
+			headers[Headers.prefersColorScheme] = "light"
+		case .dark:
+			headers[Headers.prefersColorScheme] = "dark"
+		case .automatic, .web:
+			break // Don't add header for automatic or web color schemes
+		}
+
+		return headers
+	}
+
+	func withBranding() -> [String: String] {
+		var headers = self
+
+		let colorScheme = ShopifyCheckoutSheetKit.configuration.colorScheme
+		switch colorScheme {
+		case .web:
+			headers[Headers.branding] = Headers.brandingWeb
+		default:
+			headers[Headers.branding] = Headers.brandingCheckoutKit
+		}
+
+		return headers
+	}
+
+	func hasColorSchemeHeader() -> Bool {
+		return hasHeader(Headers.prefersColorScheme)
+	}
+
+	func hasBrandingHeader() -> Bool {
+		return hasHeader(Headers.branding)
+	}
+
+	private func hasHeader(_ headerName: String) -> Bool {
+		return self.keys.contains { key in
+			key.caseInsensitiveCompare(headerName) == .orderedSame
+		}
+	}
+}

Tests/ShopifyCheckoutSheetKitTests/CheckoutBridgeTests.swift

@@ -42,20 +42,20 @@ class CheckoutBridgeTests: XCTestCase {
 	func testReturnsStandardUserAgent() {
 		let version = ShopifyCheckoutSheetKit.version
 		let schemaVersion = CheckoutBridge.schemaVersion
-		XCTAssertEqual(CheckoutBridge.applicationName, "ShopifyCheckoutSDK/\(version) (\(schemaVersion);automatic;standard)")
+		XCTAssertEqual(CheckoutBridge.applicationName, "CheckoutKit/\(version) (iOS) CheckoutSheetProtocol/\(schemaVersion)")
 	}
 
 	func testReturnsRecoveryUserAgent() {
 		let version = ShopifyCheckoutSheetKit.version
-		XCTAssertEqual(CheckoutBridge.recoveryAgent, "ShopifyCheckoutSDK/\(version) (noconnect;automatic;standard_recovery)")
+		XCTAssertEqual(CheckoutBridge.recoveryAgent, "CheckoutKit/\(version) (iOS) CheckoutSheetProtocol/noconnect")
 	}
 
 	func testReturnsUserAgentWithCustomPlatformSuffix() {
 		let version = ShopifyCheckoutSheetKit.version
 		let schemaVersion = CheckoutBridge.schemaVersion
 		ShopifyCheckoutSheetKit.configuration.platform = Platform.reactNative
-		XCTAssertEqual(CheckoutBridge.applicationName, "ShopifyCheckoutSDK/\(version) (\(schemaVersion);automatic;standard) ReactNative")
-		XCTAssertEqual(CheckoutBridge.recoveryAgent, "ShopifyCheckoutSDK/\(version) (noconnect;automatic;standard_recovery) ReactNative")
+		XCTAssertEqual(CheckoutBridge.applicationName, "CheckoutKit/\(version) (ReactNative) CheckoutSheetProtocol/\(schemaVersion)")
+		XCTAssertEqual(CheckoutBridge.recoveryAgent, "CheckoutKit/\(version) (ReactNative) CheckoutSheetProtocol/noconnect")
 		ShopifyCheckoutSheetKit.configuration.platform = nil
 	}
 
@@ -320,23 +320,23 @@ class CheckoutBridgeTests: XCTestCase {
 
 	private func expectedPresentedScript() -> String {
 		return """
-		if (window.MobileCheckoutSdk && window.MobileCheckoutSdk.dispatchMessage) {
-			window.MobileCheckoutSdk.dispatchMessage('presented');
+		if (window.Shopify?.CheckoutSheetProtocol?.postMessage) {
+			window.Shopify.CheckoutSheetProtocol.postMessage('presented');
 		} else {
 			window.addEventListener('mobileCheckoutBridgeReady', function () {
-				window.MobileCheckoutSdk.dispatchMessage('presented');
+				window.Shopify.CheckoutSheetProtocol.postMessage('presented');
 			}, {passive: true, once: true});
 		}
 		"""
 	}
 
 	private func expectedPayloadScript() -> String {
 		return """
-		if (window.MobileCheckoutSdk && window.MobileCheckoutSdk.dispatchMessage) {
-			window.MobileCheckoutSdk.dispatchMessage('payload', {"one": true});
+		if (window.Shopify?.CheckoutSheetProtocol?.postMessage) {
+			window.Shopify.CheckoutSheetProtocol.postMessage('payload', {"one": true});
 		} else {
 			window.addEventListener('mobileCheckoutBridgeReady', function () {
-				window.MobileCheckoutSdk.dispatchMessage('payload', {"one": true});
+				window.Shopify.CheckoutSheetProtocol.postMessage('payload', {"one": true});
 			}, {passive: true, once: true});
 		}
 		"""

Tests/ShopifyCheckoutSheetKitTests/CheckoutWebViewTests.swift

@@ -61,7 +61,7 @@ class CheckoutWebViewTests: XCTestCase {
 		XCTAssertTrue(recovery.isRecovery)
 		XCTAssertFalse(recovery.isBridgeAttached)
 		XCTAssertFalse(recovery.isPreloadingAvailable)
-		XCTAssertEqual(recovery.configuration.applicationNameForUserAgent, "ShopifyCheckoutSDK/\(ShopifyCheckoutSheetKit.version) (noconnect;automatic;standard_recovery)")
+		XCTAssertEqual(recovery.configuration.applicationNameForUserAgent, "CheckoutKit/\(ShopifyCheckoutSheetKit.version) (iOS) CheckoutSheetProtocol/noconnect")
 		XCTAssertTrue(recovery.configuration.allowsInlineMediaPlayback)
 		XCTAssertEqual(recovery.backgroundColor, backgroundColor)
 		XCTAssertFalse(recovery.isOpaque)