[Auth] Alternative recaptcha approach (#14217)

Author: ncooke3

FirebaseAuth/Sources/ObjC/FIRRecaptchaBridge.m

@@ -18,83 +18,23 @@
 #import "FirebaseAuth/Sources/Public/FirebaseAuth/FIRRecaptchaBridge.h"
 #import "RecaptchaInterop/RecaptchaInterop.h"
 
-// This is thread safe since it is only called by the AuthRecaptchaVerifier singleton.
-static id<RCARecaptchaClientProtocol> recaptchaClient;
-
-static void retrieveToken(NSString *actionString,
-                          NSString *fakeToken,
-                          FIRAuthRecaptchaTokenCallback callback) {
-  Class RecaptchaActionClass = NSClassFromString(@"RecaptchaEnterprise.RCAAction");
-  SEL customActionSelector = NSSelectorFromString(@"initWithCustomAction:");
-  if (!RecaptchaActionClass) {
-    // Fall back to attempting to connect with pre-18.7.0 RecaptchaEnterprise.
-    RecaptchaActionClass = NSClassFromString(@"RecaptchaAction");
-  }
-
-  if (RecaptchaActionClass &&
-      [RecaptchaActionClass instancesRespondToSelector:customActionSelector]) {
-    // Initialize with a custom action
-    id (*funcWithCustomAction)(id, SEL, NSString *) = (id(*)(
-        id, SEL, NSString *))[RecaptchaActionClass instanceMethodForSelector:customActionSelector];
-
-    id<RCAActionProtocol> customAction =
-        funcWithCustomAction([RecaptchaActionClass alloc], customActionSelector, actionString);
-    if (customAction) {
-      [recaptchaClient execute:customAction
-                    completion:^(NSString *_Nullable token, NSError *_Nullable error) {
-                      if (!error) {
-                        callback(token, nil, YES, YES);
-                        return;
-                      } else {
-                        callback(fakeToken, nil, YES, YES);
-                      }
-                    }];
-    } else {
-      // RecaptchaAction class creation failed.
-      callback(@"", nil, YES, NO);
-    }
-
+Class<RCARecaptchaProtocol> _Nonnull __fir_castToRecaptchaProtocolFromClass(Class _Nonnull klass) {
+  if ([klass conformsToProtocol:@protocol(RCARecaptchaProtocol)]) {
+    NSLog(@"RCARecaptchaProtocol - true");
   } else {
-    // RecaptchaEnterprise not linked.
-    callback(@"", nil, NO, NO);
+    NSLog(@"RCARecaptchaProtocol - false");
   }
+  return (Class<RCARecaptchaProtocol>)klass;
 }
 
-void FIRRecaptchaGetToken(NSString *siteKey,
-                          NSString *actionString,
-                          NSString *fakeToken,
-                          FIRAuthRecaptchaTokenCallback callback) {
-  if (recaptchaClient != nil) {
-    retrieveToken(actionString, fakeToken, callback);
-    return;
-  }
-
-  // Why not use `conformsToProtocol`?
-  Class RecaptchaClass = NSClassFromString(@"RecaptchaEnterprise.RCARecaptcha");
-  SEL selector = NSSelectorFromString(@"fetchClientWithSiteKey:completion:");
-  if (!RecaptchaClass) {
-    // Fall back to attempting to connect with pre-18.7.0 RecaptchaEnterprise.
-    RecaptchaClass = NSClassFromString(@"Recaptcha");
-    selector = NSSelectorFromString(@"getClientWithSiteKey:completion:");
-  }
-
-  if (RecaptchaClass && [RecaptchaClass respondsToSelector:selector]) {
-    void (*funcWithoutTimeout)(id, SEL, NSString *,
-                               void (^)(id<RCARecaptchaClientProtocol> _Nullable recaptchaClient,
-                                        NSError *_Nullable error)) =
-        (void *)[RecaptchaClass methodForSelector:selector];
-    funcWithoutTimeout(RecaptchaClass, selector, siteKey,
-                       ^(id<RCARecaptchaClientProtocol> _Nonnull client, NSError *_Nullable error) {
-                         if (error) {
-                           callback(@"", error, YES, YES);
-                         } else {
-                           recaptchaClient = client;
-                           retrieveToken(actionString, fakeToken, callback);
-                         }
-                       });
+Class<RCAActionProtocol> _Nonnull __fir_castToRecaptchaActionProtocolFromClass(
+    Class _Nonnull klass) {
+  if ([klass conformsToProtocol:@protocol(RCAActionProtocol)]) {
+    NSLog(@"RCAActionProtocol - true");
   } else {
-    // RecaptchaEnterprise not linked.
-    callback(@"", nil, NO, NO);
+    NSLog(@"RCAActionProtocol - false");
   }
+  return (Class<RCAActionProtocol>)klass;
 }
+
 #endif

FirebaseAuth/Sources/Public/FirebaseAuth/FIRRecaptchaBridge.h

@@ -17,17 +17,12 @@
 
 #if TARGET_OS_IOS
 
-typedef void (^FIRAuthRecaptchaTokenCallback)(NSString *_Nonnull token,
-                                              NSError *_Nullable error,
-                                              BOOL linked,
-                                              BOOL recaptchaActionCreated);
+@protocol RCARecaptchaProtocol;
+@protocol RCAActionProtocol;
+
+Class<RCARecaptchaProtocol> _Nonnull __fir_castToRecaptchaProtocolFromClass(Class _Nonnull klass);
+
+Class<RCAActionProtocol> _Nonnull __fir_castToRecaptchaActionProtocolFromClass(
+    Class _Nonnull klass);
 
-// Provide a bridge to the Objective-C protocol provided by the optional Recaptcha Enterprise
-// dependency. Once the Recaptcha Enterprise provides a Swift interop protocol, this C and
-// Objective-C code can be converted to Swift. Casting to a Objective-C protocol does not seem
-// possible in Swift. The C API is a workaround for linkage problems with an Objective-C API.
-void FIRRecaptchaGetToken(NSString *_Nonnull siteKey,
-                          NSString *_Nonnull actionString,
-                          NSString *_Nonnull fakeToken,
-                          _Nonnull FIRAuthRecaptchaTokenCallback callback);
 #endif

FirebaseAuth/Sources/Swift/Utilities/AuthRecaptchaVerifier.swift

@@ -177,6 +177,7 @@
       } else if let recaptcha = NSClassFromString("Recaptcha") {
         // Fall back to attempting to connect with pre-18.7.0 RecaptchaEnterprise.
         do {
+          let recaptcha = __fir_castToRecaptchaProtocolFromClass(recaptcha)
           let client = try await recaptcha.getClient(withSiteKey: siteKey)
           recaptchaClient = client
           return await retrieveToken(actionString: actionString, fakeToken: fakeToken)
@@ -192,18 +193,21 @@
     private func retrieveToken(actionString: String,
                                fakeToken: String) async -> (token: String, error: Error?,
                                                             linked: Bool, actionCreated: Bool) {
-      let recaptchaAction = (
-        NSClassFromString("RecaptchaEnterprise.RCAAction") ?? NSClassFromString("RecaptchaAction")
-      ) as? RCAActionProtocol.Type
-
-      guard let recaptchaAction else {
+      if let recaptchaAction =
+        NSClassFromString("RecaptchaEnterprise.RCAAction") as? RCAActionProtocol.Type {
+        let action = recaptchaAction.init(customAction: actionString)
+        let token = try? await recaptchaClient!.execute(withAction: action)
+        return (token ?? "NO_RECAPTCHA", nil, true, true)
+      } else if let recaptchaAction = NSClassFromString("RecaptchaAction") {
+        // Fall back to attempting to connect with pre-18.7.0 RecaptchaEnterprise.
+        let recaptchaAction = __fir_castToRecaptchaActionProtocolFromClass(recaptchaAction)
+        let action = recaptchaAction.init(customAction: actionString)
+        let token = try? await recaptchaClient!.execute(withAction: action)
+        return (token ?? "NO_RECAPTCHA", nil, true, true)
+      } else {
         // RecaptchaEnterprise not linked.
         return ("", nil, false, false)
       }
-
-      let action = recaptchaAction.init(customAction: actionString)
-      let token = try? await recaptchaClient!.execute(withAction: action)
-      return (token ?? "NO_RECAPTCHA", nil, true, true)
     }
 
     func retrieveRecaptchaConfig(forceRefresh: Bool) async throws {