Properly warn if auth token is rejected by the RT DB server

This aligns with Android implementation, which would warn when the token is rejected for more than 3 time.
https://cs.corp.google.com/piper///depot/google3/java/com/google/android/gmscore/dev/client/firebase-database-connection/src/com/google/firebase/database/connection/PersistentConnectionImpl.java?l=844

For desktop implementation, it would attempt to reconnect immediately.  The retry windows should be implemented in b/123780315.

PiperOrigin-RevId: 246433502

Author: chkuang-g

database/src/desktop/connection/persistent_connection.cc

@@ -86,6 +86,8 @@ const char* PersistentConnection::kServerDataTag = "t";
 const char* PersistentConnection::kServerDataWarnings = "w";
 const char* PersistentConnection::kServerResponseData = "d";
 
+int PersistentConnection::kInvalidAuthTokenThreshold = 3;
+
 compat::Atomic<uint32_t> PersistentConnection::next_log_id_(0);
 
 // Util function to print QuerySpec in debug logs.
@@ -108,6 +110,7 @@ PersistentConnection::PersistentConnection(
       realtime_(nullptr),
       connection_state_(kDisconnected),
       is_first_connection_(true),
+      invalid_auth_token_count(0),
       next_request_id_(0),
       force_auth_refresh_(false),
       next_listen_id_(0),
@@ -926,6 +929,7 @@ void PersistentConnection::HandleAuthTokenResponse(const Variant& message,
   std::string status = GetStringValue(message, kRequestStatus);
 
   if (status == kRequestStatusOk) {
+    invalid_auth_token_count = 0;
     event_handler_->OnAuthStatus(true);
     LogDebug("%s Authentication success", log_id_.c_str());
 
@@ -944,8 +948,25 @@ void PersistentConnection::HandleAuthTokenResponse(const Variant& message,
              status.c_str(), reason.c_str());
     realtime_->Close();
 
-    // TODO(chkuang): schedule another time to retrieve and send another auth
-    // token
+    Error error = StatusStringToErrorCode(status);
+    if (error == kErrorInvalidToken) {
+      // We'll wait a couple times before logging the warning / increasing the
+      // retry period since oauth tokens will report as "invalid" if they're
+      // just expired. Plus there may be transient issues that resolve
+      // themselves.
+      ++invalid_auth_token_count;
+
+      if (invalid_auth_token_count >= kInvalidAuthTokenThreshold) {
+        // TODO(chkuang): Maximize retry interval (after retry is properly
+        //                implemented).
+        LogWarning(
+            "Provided authentication credentials are invalid. This indicates "
+            "your FirebaseApp instance was not initialized correctly. Make "
+            "sure your google-services.json file has the correct firebase_url "
+            "and api_key. You can re-download google-services.json from "
+            "https://console.firebase.google.com/.");
+      }
+    }
   }
 }
 

database/src/desktop/connection/persistent_connection.h

@@ -455,6 +455,8 @@ class PersistentConnection : public ConnectionEventHandler {
   static const char* kServerDataWarnings;
   static const char* kServerResponseData;
 
+  static int kInvalidAuthTokenThreshold;
+
   // Log id.  Unique for each persistent connection.
   static compat::Atomic<uint32_t> next_log_id_;
   std::string log_id_;
@@ -489,6 +491,9 @@ class PersistentConnection : public ConnectionEventHandler {
   // Session
   std::string last_session_id_;
 
+  // Number of time when auth token is rejected by the server
+  int invalid_auth_token_count;
+
   // Request/Response
   uint64_t next_request_id_;
   std::map<uint64_t, RequestDataPtr> request_map_;