Merge pull request #1962 from firebase/md-fdl

Add support for validating FDL links from custom domains. This feature is not yet enabled in the backend.

Author: dmandar

Example/DynamicLinks/App/iOS/DL-Info.plist

@@ -50,5 +50,11 @@
 		<string>UIInterfaceOrientationLandscapeLeft</string>
 		<string>UIInterfaceOrientationLandscapeRight</string>
 	</array>
+	<key>FirebaseDynamicLinksCustomDomains</key>
+	<array>
+		<string>https://google.com</string>
+		<string>https://google.com/one</string>
+		<string>https://a.firebase.com/mypath</string>
+	</array>
 </dict>
 </plist>

Example/DynamicLinks/FDLBuilderTestAppObjC/AppDelegate.m

@@ -60,7 +60,8 @@ - (BOOL)application:(UIApplication *)application
 
 - (BOOL)application:(UIApplication *)application
     continueUserActivity:(NSUserActivity *)userActivity
-      restorationHandler:(void (^)(NSArray *))restorationHandler {
+      restorationHandler:
+          (void (^)(NSArray<id<UIUserActivityRestoring>> *_Nullable))restorationHandler {
   BOOL handled = [[FIRDynamicLinks dynamicLinks]
       handleUniversalLink:userActivity.webpageURL
                completion:^(FIRDynamicLink *_Nullable dynamicLink, NSError *_Nullable error) {

Example/DynamicLinks/FDLBuilderTestAppObjC/Info.plist

@@ -2,6 +2,20 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
 	<key>CFBundleURLTypes</key>
 	<array>
 		<dict>
@@ -55,22 +69,22 @@
 			</array>
 		</dict>
 	</array>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>en</string>
-	<key>CFBundleExecutable</key>
-	<string>$(EXECUTABLE_NAME)</string>
-	<key>CFBundleIdentifier</key>
-	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleName</key>
-	<string>$(PRODUCT_NAME)</string>
-	<key>CFBundlePackageType</key>
-	<string>APPL</string>
-	<key>CFBundleShortVersionString</key>
-	<string>1.0</string>
 	<key>CFBundleVersion</key>
 	<string>1</string>
+	<key>FirebaseDynamicLinksCustomDomains</key>
+	<array>
+		<string>https://mydomain.com</string>
+		<string>https://mydomain2.com</string>
+		<string>https://google.com</string>
+		<string>https://google.com</string>
+		<string>google</string>
+		<string>mydomain.com</string>
+		<string>https://mydomain</string>
+		<string>https://mydomain3.com</string>
+		<string>https://google.com/one</string>
+		<string>https://custom.com/one/two</string>
+		<string>https://custom1.com/one/</string>
+	</array>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>UILaunchStoryboardName</key>

Example/DynamicLinks/FDLBuilderTestAppObjCTests/Info.plist

@@ -18,5 +18,24 @@
 	<string>1.0</string>
 	<key>CFBundleVersion</key>
 	<string>1</string>
+	<key>&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
+&lt;!DOCTYPE plist PUBLIC &quot;-//Apple//DTD PLIST 1.0//EN&quot; &quot;http://www.apple.com/DTDs/PropertyList-1.0.dtd&quot;&gt;
+&lt;plist version=&quot;1.0&quot;&gt;
+&lt;array&gt;
+	&lt;string&gt;https://mydomain.com&lt;/string&gt;
+	&lt;string&gt;https://mydomain2.com&lt;/string&gt;
+	&lt;string&gt;https://google.com&lt;/string&gt;
+	&lt;string&gt;https://google.com&lt;/string&gt;
+	&lt;string&gt;go&lt;/string&gt;
+	&lt;string&gt;g.co&lt;/string&gt;
+	&lt;string&gt;https://go&lt;/string&gt;
+	&lt;string&gt;https://g.co&lt;/string&gt;
+	&lt;string&gt;https://google.com/one&lt;/string&gt;
+	&lt;string&gt;https://custom.com/one/two&lt;/string&gt;
+	&lt;string&gt;https://custom1.com/one/&lt;/string&gt;
+&lt;/array&gt;
+&lt;/plist&gt;
+</key>
+	<string></string>
 </dict>
 </plist>

Example/DynamicLinks/Tests/FIRDynamicLinksTest.m

@@ -1015,6 +1015,57 @@ - (void)testSelfDiagnoseCompletionCalled {
   [self waitForExpectationsWithTimeout:2.0 handler:nil];
 }
 
+#pragma mark - Custom domain tests
+- (void)testValidCustomDomainNames {
+  // Entries in plist file:
+  //  https://google.com
+  //  https://google.com/one
+  //  https://a.firebase.com/mypath
+
+  NSArray<NSString *> *urlStrings = @[
+    @"https://google.com/1",                            // Valid domain. Any path.
+    @"https://google.com/2",                            // Valid domain. Any path.
+    @"https://google.com/one",                          // Valid domain. Specified path.
+    @"https://a.firebase.com/mypath/",                  // Valid subdomain.
+    @"https://a.firebase.com/mypath/abcd/efgh",         // Long path.
+    @"https://a.firebase.com/mypath?link=abcd&test=1",  // Long path.
+  ];
+
+  for (NSString *urlString in urlStrings) {
+    NSURL *url = [NSURL URLWithString:urlString];
+    BOOL matchesShortLinkFormat = [self.service matchesShortLinkFormat:url];
+
+    XCTAssertTrue(matchesShortLinkFormat,
+                  @"Non-DDL domain URL matched short link format with URL: %@", url);
+  }
+}
+
+- (void)testInvalidCustomDomainNames {
+  // Entries in plist file:
+  //  https://google.com
+  //  https://google.com/one
+  //  https://a.firebase.com/mypath
+
+  NSArray<NSString *> *urlStrings = @[
+    @"mydomain.com",                  // Domain not in plist. Also, no scheme.
+    @"http://mydomain",               // Domain not in plist. No path.
+    @"google.com",                    // Valid domain. No scheme.
+    @"https://google.com",            // Valid domain. No path.
+    @"http://google.com",             // Valid domain. Invalid scheme.
+    @"https://google.co.in/abc",      // Invalid domain starts with valid domain name.
+    @"https://firebase.com/mypath",   // Invalid (sub)domain.
+    @"https://b.firebase.com/mypath"  // Invalid subdomain.
+  ];
+
+  for (NSString *urlString in urlStrings) {
+    NSURL *url = [NSURL URLWithString:urlString];
+    BOOL matchesShortLinkFormat = [self.service matchesShortLinkFormat:url];
+
+    XCTAssertFalse(matchesShortLinkFormat,
+                   @"Non-DDL domain URL matched short link format with URL: %@", url);
+  }
+}
+
 #pragma mark - Private Helpers
 
 - (void)removeAllFIRApps {

Firebase/DynamicLinks/FIRDynamicLinks.m

@@ -60,6 +60,9 @@
 // We should only open url once. We use the following key to store the state in the user defaults.
 static NSString *const kFIRDLOpenURLKey = @"com.google.appinvite.openURL";
 
+// Custom domains to be whitelisted are optionally added as an array to the info.plist.
+static NSString *const kInfoPlistCustomDomainsKey = @"FirebaseDynamicLinksCustomDomains";
+
 NS_ASSUME_NONNULL_BEGIN
 
 @interface FIRDynamicLinks () <FIRDLRetrievalProcessDelegate>
@@ -216,6 +219,12 @@ - (void)configureDynamicLinks:(FIRApp *)app {
     }
     [NSException raise:kFirebaseDurableDeepLinkErrorDomain format:@"%@", message];
   }
+  // Check to see if FirebaseDynamicLinksCustomDomains array is present.
+  NSDictionary *infoDictionary = [NSBundle mainBundle].infoDictionary;
+  NSArray *customDomains = infoDictionary[kInfoPlistCustomDomainsKey];
+  if (customDomains) {
+    FIRDLAddToWhiteListForCustomDomainsArray(customDomains);
+  }
 }
 
 - (instancetype)initWithAnalytics:(nullable id<FIRAnalyticsInterop>)analytics {

Firebase/DynamicLinks/Utilities/FDLUtilities.h

@@ -136,4 +136,9 @@ BOOL FIRDLMatchesShortLinkFormat(NSURL *URL);
  */
 NSString *FIRDLMatchTypeStringFromServerString(NSString *_Nullable serverMatchTypeString);
 
+/**
+ Add custom domains from the info.plist to the internal whitelist.
+ */
+void FIRDLAddToWhiteListForCustomDomainsArray(NSArray *_Nonnull customDomains);
+
 NS_ASSUME_NONNULL_END

Firebase/DynamicLinks/Utilities/FDLUtilities.m

@@ -32,6 +32,7 @@
 NSString *const kFIRDLParameterWeakMatchEndpoint = @"invitation_weakMatchEndpoint";
 NSString *const kFIRDLParameterMatchMessage = @"match_message";
 NSString *const kFIRDLParameterRequestIPVersion = @"request_ip_version";
+static NSSet *FIRDLCustomDomains = nil;
 
 NSURL *FIRDLCookieRetrievalURL(NSString *urlScheme, NSString *bundleID) {
   static NSString *const kFDLBundleIDQueryParameterName = @"fdl_ios_bundle_id";
@@ -192,6 +193,23 @@ BOOL FIRDLOSVersionSupported(NSString *_Nullable systemVersion, NSString *minSup
   return timeZoneName;
 }
 
+BOOL FIRDLIsURLForWhiteListedCustomDomain(NSURL *_Nullable URL) {
+  BOOL customDomainMatchFound = false;
+  for (NSURL *allowedCustomDomain in FIRDLCustomDomains) {
+    // All custom domain host names should match at a minimum.
+    if ([allowedCustomDomain.host isEqualToString:URL.host]) {
+      // Next, do a string compare to check if the full path matches as well.
+      if (([URL.absoluteString rangeOfString:allowedCustomDomain.absoluteString
+                                     options:NSCaseInsensitiveSearch | NSAnchoredSearch]
+               .location) == 0) {
+        customDomainMatchFound = true;
+        break;
+      }
+    }
+  }
+  return customDomainMatchFound;
+}
+
 BOOL FIRDLCanParseUniversalLinkURL(NSURL *_Nullable URL) {
   // Handle universal links with format |https://goo.gl/app/<appcode>?<parameters>|.
   // Also support page.link format.
@@ -200,7 +218,11 @@ BOOL FIRDLCanParseUniversalLinkURL(NSURL *_Nullable URL) {
   // Handle universal links with format |https://<appcode>.app.goo.gl?<parameters>| and page.link.
   BOOL isDDLWithSubdomain =
       [URL.host hasSuffix:@".app.goo.gl"] || [URL.host hasSuffix:@".page.link"];
-  return isDDLWithAppcodeInPath || isDDLWithSubdomain;
+
+  // Handle universal links for custom domains.
+  BOOL isDDLWithCustomDomain = FIRDLIsURLForWhiteListedCustomDomain(URL);
+
+  return isDDLWithAppcodeInPath || isDDLWithSubdomain || isDDLWithCustomDomain;
 }
 
 BOOL FIRDLMatchesShortLinkFormat(NSURL *URL) {
@@ -227,4 +249,19 @@ BOOL FIRDLMatchesShortLinkFormat(NSURL *URL) {
   return matchMap[serverMatchTypeString] ?: @"none";
 }
 
+void FIRDLAddToWhiteListForCustomDomainsArray(NSArray *_Nonnull customDomains) {
+  // Duplicates will be weeded out when converting to a set.
+  NSMutableArray *validCustomDomains =
+      [[NSMutableArray alloc] initWithCapacity:customDomains.count];
+  for (NSString *customDomainEntry in customDomains) {
+    NSURL *customDomainURL = [NSURL URLWithString:customDomainEntry];
+    // We require a valid scheme for each custom domain enumerated in the info.plist file.
+    if (customDomainURL && customDomainURL.scheme) {
+      [validCustomDomains addObject:customDomainURL];
+    }
+  }
+  // Duplicates will be weeded out when converting to a set.
+  FIRDLCustomDomains = [NSSet setWithArray:validCustomDomains];
+}
+
 NS_ASSUME_NONNULL_END