update external link interceptor with optional param to override defa…

Sources/ShopifyCheckout/CheckoutView.swift

@@ -122,7 +122,7 @@ extension CheckoutView: WKNavigationDelegate {
 		}
 
 		if isExternalLink(action) || isMailOrTelLink(url) {
-			viewDelegate?.checkoutViewDidClickLink(url: url)
+			viewDelegate?.checkoutViewDidClickLink(url: removeExternalParam(url))
 			decisionHandler(.cancel)
 			return
 		}
@@ -170,9 +170,24 @@ extension CheckoutView: WKNavigationDelegate {
     }
 
 	private func isExternalLink(_ action: WKNavigationAction) -> Bool {
-		return action.navigationType == .linkActivated && action.targetFrame == nil
+		if action.navigationType == .linkActivated && action.targetFrame == nil { return true }
+
+		guard let url = action.request.url else { return false }
+		guard let url = URLComponents(url: url, resolvingAgainstBaseURL: false) else { return false }
+
+		guard let openExternally = url.queryItems?.first(where: { $0.name == "open_externally" })?.value else { return false }
+
+		return openExternally.lowercased() == "true" || openExternally == "1"
 	}
 
+	private func removeExternalParam(_ url: URL) -> URL {
+		guard var urlComponents = URLComponents(url: url, resolvingAgainstBaseURL: false) else {
+			return url
+		}
+		urlComponents.queryItems = urlComponents.queryItems?.filter { !($0.name == "open_externally") }
+		return urlComponents.url ?? url
+    }
+
 	private func isMailOrTelLink(_ url: URL) -> Bool {
 		return ["mailto", "tel"].contains(url.scheme)
 	}

Tests/ShopifyCheckoutTests/CheckoutViewTests.swift

@@ -86,6 +86,23 @@ class CheckoutViewTests: XCTestCase {
 		wait(for: [didClickLinkExpectation], timeout: 1)
 	}
 
+	func testURLLinkDelegationWithExternalParam() {
+		let link = URL(string: "https://www.shopify.com/legal/privacy/app-users?open_externally=true")!
+
+		let delegate = MockCheckoutViewDelegate()
+		let didClickLinkExpectation = expectation(
+			description: "checkoutViewDidClickLink was called"
+		)
+		delegate.didClickLinkExpectation = didClickLinkExpectation
+		view.viewDelegate = delegate
+
+		view.webView(view, decidePolicyFor: MockExternalNavigationAction(url: link, navigationType: .other)) { policy in
+			XCTAssertEqual(policy, .cancel)
+		}
+
+		wait(for: [didClickLinkExpectation], timeout: 1)
+	}
+
     func test410responseOnCheckoutURLCodeDelegation() {
 		view.load(checkout: URL(string: "http://shopify1.shopify.com/checkouts/cn/123")!)
 		let link = view.url!

Tests/ShopifyCheckoutTests/Mocks/MockNavigationAction.swift

@@ -38,21 +38,23 @@ class MockNavigationAction: WKNavigationAction {
 
 class MockExternalNavigationAction: WKNavigationAction {
 	private let mockRequest: URLRequest
+	private let navType: WKNavigationType
 
 	override var request: URLRequest {
 		return mockRequest
 	}
 
 	override var navigationType: WKNavigationType {
-		return .linkActivated
+		return self.navType
 	}
 
 	override var targetFrame: WKFrameInfo? {
 		return nil
 	}
 
-	init(url: URL) {
+	init(url: URL, navigationType: WKNavigationType = .linkActivated) {
 		self.mockRequest = URLRequest(url: url)
+		self.navType = navigationType
 		super.init()
 	}
 }