[firebase_core]: CORS Error When Accessing Firebase Emulator UI via Project IDX

Is there an existing issue for this?

[X] I have searched the existing issues.

Which plugins are affected?

Core

Which platforms are affected?

Web

Description

I am using the Project IDX online IDE to run the Firebase Emulator and accessing the link provided by Project IDX on port 4000:

https://4000-idx-xxxxxxxxx-1722318992255.cluster-qpa6grkipzc64wfjrbr3hsdma2.cloudworkstations.dev/

I am encountering a CORS error when trying to view the Firebase Emulator UI through the browser. However, the emulator is accessible from a Flutter app, only the browser access is blocked by CORS policy.

Error Message:

https://4000-idx-xxxxxxx-1722318992255.cluster-qpa6grkipzc64wfjrbr3hsdma2.cloudworkstations.dev' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Reproducing the issue

Use Project IDX online IDE to run Firebase Emulator. Access the link provided by Project IDX on port 4000 through a browser: https://4000-idx-xxxxxxxxx-1722318992255.cluster-qpa6grkipzc64wfjrbr3hsdma2.cloudworkstations.dev/ Observe the CORS error in the browser console.

Firebase Core version

node@377e77b1b504:~$ firebase --version 13.14.2 node@377e77b1b504:~$

Flutter Version

3.22.2

Relevant Log Output

'Access to XMLHttpRequest at 'https://4000-idx-xxxxxxx-1722318992255.cluster-qpa6grkipzc64wfjrbr3hsdma2.cloudworkstations.dev' from origin 'http://localhost:4000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Flutter dependencies

Expand Flutter dependencies snippet

```yaml xxxxxx-7371638:~/xxxxxxx{main}$ flutter pub deps -- --style=compact Dart SDK 3.4.3 Flutter SDK 3.22.2 xxxxxxxx 0.0.2+1 dependencies: - back_button_interceptor 7.0.3 [collection flutter] - cached_network_image 3.3.1 [cached_network_image_platform_interface cached_network_image_web flutter flutter_cache_manager octo_image] - clipboard 0.1.3 [flutter] - cloud_firestore 4.15.9 [cloud_firestore_platform_interface cloud_firestore_web collection firebase_core firebase_core_platform_interface flutter meta] - equatable 2.0.5 [collection meta] - file_picker 6.2.0 [flutter flutter_web_plugins flutter_plugin_android_lifecycle plugin_platform_interface ffi path win32] - firebase_analytics 10.8.10 [firebase_analytics_platform_interface firebase_analytics_web firebase_core firebase_core_platform_interface flutter] - firebase_auth 4.17.9 [firebase_auth_platform_interface firebase_auth_web firebase_core firebase_core_platform_interface flutter meta] - firebase_core 2.27.1 [firebase_core_platform_interface firebase_core_web flutter meta] - firebase_storage 11.6.10 [firebase_core firebase_core_platform_interface firebase_storage_platform_interface firebase_storage_web flutter] - firebase_ui_auth 1.13.1 [email_validator firebase_auth firebase_core firebase_dynamic_links firebase_ui_localizations firebase_ui_oauth firebase_ui_shared flutter flutter_localizations meta] - firebase_ui_oauth_google 1.3.1 [firebase_auth firebase_ui_oauth flutter google_sign_in] - flutter 0.0.0 [characters collection material_color_utilities meta vector_math sky_engine] - flutter_bloc 8.1.5 [bloc flutter provider] - flutter_line_sdk 2.3.6 [flutter] - flutter_udid 3.0.0 [flutter crypto] - go_router 13.2.4 [collection flutter flutter_web_plugins logging meta] - google_mobile_ads 4.0.0 [meta flutter webview_flutter_android webview_flutter_wkwebview webview_flutter] - http 1.2.1 [async http_parser meta web] - image 4.1.7 [archive meta xml] - infinite_scroll_pagination 4.0.0 [flutter flutter_staggered_grid_view sliver_tools] - intl 0.19.0 [clock meta path] - jwt_decoder 2.0.1 - like_button 2.0.5 [flutter] - logger 2.1.0 - modal_bottom_sheet 3.0.0 [flutter] - path_provider 2.1.2 [flutter path_provider_android path_provider_foundation path_provider_linux path_provider_platform_interface path_provider_windows] - pigeon 17.1.2 [analyzer args collection meta path yaml] - readmore 3.0.0 [flutter] - shared_preferences 2.2.2 [flutter shared_preferences_android shared_preferences_foundation shared_preferences_linux shared_preferences_platform_interface shared_preferences_web shared_preferences_windows] - sign_in_with_apple 6.0.0 [flutter meta sign_in_with_apple_platform_interface sign_in_with_apple_web] - universal_html 2.2.4 [async csslib charcode collection html meta source_span typed_data universal_io] - url_launcher 6.2.5 [flutter url_launcher_android url_launcher_ios url_launcher_linux url_launcher_macos url_launcher_platform_interface url_launcher_web url_launcher_windows] - uuid 4.3.3 [crypto sprintf meta fixnum] - video_player 2.8.3 [flutter html video_player_android video_player_avfoundation video_player_platform_interface video_player_web] dev dependencies: - fake_cloud_firestore 2.4.8 [flutter cloud_firestore cloud_firestore_platform_interface collection plugin_platform_interface quiver rxdart mock_exceptions fake_firebase_security_rules rx equatable clock] - flutter_lints 3.0.1 [lints] - flutter_test 0.0.0 [flutter test_api matcher path fake_async clock stack_trace vector_math leak_tracker_flutter_testing async boolean_selector characters collection leak_tracker leak_tracker_testing material_color_utilities meta source_span stream_channel string_scanner term_glyph vm_service] - test 1.25.2 [analyzer async boolean_selector collection coverage http_multi_server io js matcher node_preamble package_config path pool shelf shelf_packages_handler shelf_static shelf_web_socket source_span stack_trace stream_channel test_api test_core typed_data web_socket_channel webkit_inspection_protocol yaml] transitive dependencies: - _fe_analyzer_shared 67.0.0 [meta] - _flutterfire_internals 1.3.26 [collection firebase_core firebase_core_platform_interface flutter meta] - analyzer 6.4.1 [_fe_analyzer_shared collection convert crypto glob meta package_config path pub_semver source_span watcher yaml] - antlr4 4.13.1 [logging collection] - archive 3.4.10 [crypto path pointycastle] - args 2.4.2 - async 2.11.0 [collection meta] - bloc 8.1.4 [meta] - boolean_selector 2.1.1 [source_span string_scanner] - cached_network_image_platform_interface 4.0.0 [flutter flutter_cache_manager] - cached_network_image_web 1.1.1 [cached_network_image_platform_interface flutter flutter_cache_manager] - cel 0.5.3 [antlr4 collection equatable] - characters 1.3.0 - charcode 1.3.1 - clock 1.1.1 - cloud_firestore_platform_interface 6.1.10 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface] - cloud_firestore_web 3.10.9 [_flutterfire_internals cloud_firestore_platform_interface collection firebase_core firebase_core_web flutter flutter_web_plugins js] - collection 1.18.0 - convert 3.1.1 [typed_data] - coverage 1.7.2 [args logging package_config path source_maps stack_trace vm_service] - crypto 3.0.3 [typed_data] - csslib 1.0.0 [source_span] - desktop_webview_auth 0.0.15 [crypto flutter http flutter_web_plugins plugin_platform_interface] - email_validator 2.1.17 - fake_async 1.3.1 [clock collection] - fake_firebase_security_rules 0.5.3 [antlr4 cel equatable logger tuple] - ffi 2.1.2 - file 7.0.0 [meta path] - firebase_analytics_platform_interface 3.9.10 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface] - firebase_analytics_web 0.5.5+22 [_flutterfire_internals firebase_analytics_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins js] - firebase_auth_platform_interface 7.1.9 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface] - firebase_auth_web 5.10.0 [firebase_auth_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins http_parser js meta web] - firebase_core_platform_interface 5.0.0 [collection flutter flutter_test meta plugin_platform_interface] - firebase_core_web 2.12.0 [firebase_core_platform_interface flutter flutter_web_plugins js meta web] - firebase_dynamic_links 5.4.18 [firebase_core firebase_core_platform_interface firebase_dynamic_links_platform_interface flutter meta plugin_platform_interface] - firebase_dynamic_links_platform_interface 0.2.6+26 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface] - firebase_storage_platform_interface 5.1.13 [_flutterfire_internals collection firebase_core flutter meta plugin_platform_interface] - firebase_storage_web 3.8.0 [_flutterfire_internals async firebase_core firebase_core_web firebase_storage_platform_interface flutter flutter_web_plugins http js meta web] - firebase_ui_localizations 1.10.2 [flutter flutter_localizations path] - firebase_ui_oauth 1.5.1 [desktop_webview_auth firebase_auth firebase_ui_auth firebase_ui_shared flutter_svg flutter] - firebase_ui_shared 1.4.1 [flutter] - fixnum 1.1.0 - flutter_cache_manager 3.3.1 [clock collection file flutter http path path_provider rxdart sqflite uuid] - flutter_localizations 0.0.0 [flutter intl characters clock collection material_color_utilities meta path vector_math] - flutter_plugin_android_lifecycle 2.0.17 [flutter] - flutter_staggered_grid_view 0.7.0 [flutter] - flutter_svg 2.0.10+1 [flutter http vector_graphics vector_graphics_codec vector_graphics_compiler] - flutter_web_plugins 0.0.0 [flutter characters collection material_color_utilities meta vector_math] - frontend_server_client 3.2.0 [async path] - glob 2.1.2 [async collection file path string_scanner] - google_identity_services_web 0.3.1+1 [meta web] - google_sign_in 6.2.1 [flutter google_sign_in_android google_sign_in_ios google_sign_in_platform_interface google_sign_in_web] - google_sign_in_android 6.1.21 [flutter google_sign_in_platform_interface] - google_sign_in_ios 5.7.4 [flutter google_sign_in_platform_interface] - google_sign_in_platform_interface 2.4.5 [flutter plugin_platform_interface] - google_sign_in_web 0.12.4 [flutter flutter_web_plugins google_identity_services_web google_sign_in_platform_interface http web] - html 0.15.4 [csslib source_span] - http_multi_server 3.2.1 [async] - http_parser 4.0.2 [collection source_span string_scanner typed_data] - io 1.0.4 [meta path string_scanner] - js 0.6.7 [meta] - leak_tracker 10.0.4 [clock collection meta path vm_service] - leak_tracker_flutter_testing 3.0.3 [flutter leak_tracker leak_tracker_testing matcher meta] - leak_tracker_testing 3.0.1 [leak_tracker matcher meta] - lints 3.0.0 - logging 1.2.0 - matcher 0.12.16+1 [async meta stack_trace term_glyph test_api] - material_color_utilities 0.8.0 [collection] - meta 1.12.0 - mime 1.0.5 - mock_exceptions 0.8.2 [matcher] - more 4.2.0 [characters clock collection meta] - nested 1.0.0 [flutter] - node_preamble 2.0.2 - octo_image 2.0.0 [flutter] - package_config 2.1.0 [path] - path 1.9.0 - path_parsing 1.0.1 [vector_math meta] - path_provider_android 2.2.2 [flutter path_provider_platform_interface] - path_provider_foundation 2.3.2 [flutter path_provider_platform_interface] - path_provider_linux 2.2.1 [ffi flutter path path_provider_platform_interface xdg_directories] - path_provider_platform_interface 2.1.2 [flutter platform plugin_platform_interface] - path_provider_windows 2.2.1 [ffi flutter path path_provider_platform_interface win32] - petitparser 6.0.2 [meta] - platform 3.1.4 - plugin_platform_interface 2.1.8 [meta] - pointycastle 3.7.4 [collection convert js] - pool 1.5.1 [async stack_trace] - provider 6.1.2 [collection flutter nested] - pub_semver 2.1.4 [collection meta] - quiver 3.2.1 [matcher] - rx 0.3.0 [collection matcher meta more] - rxdart 0.27.7 - shared_preferences_android 2.2.1 [flutter shared_preferences_platform_interface] - shared_preferences_foundation 2.3.5 [flutter shared_preferences_platform_interface] - shared_preferences_linux 2.3.2 [file flutter path path_provider_linux path_provider_platform_interface shared_preferences_platform_interface] - shared_preferences_platform_interface 2.3.2 [flutter plugin_platform_interface] - shared_preferences_web 2.3.0 [flutter flutter_web_plugins shared_preferences_platform_interface web] - shared_preferences_windows 2.3.2 [file flutter path path_provider_platform_interface path_provider_windows shared_preferences_platform_interface] - shelf 1.4.1 [async collection http_parser path stack_trace stream_channel] - shelf_packages_handler 3.0.2 [path shelf shelf_static] - shelf_static 1.1.2 [convert http_parser mime path shelf] - shelf_web_socket 1.0.4 [shelf stream_channel web_socket_channel] - sign_in_with_apple_platform_interface 1.0.0 [flutter plugin_platform_interface meta] - sign_in_with_apple_web 2.0.0 [flutter flutter_web_plugins sign_in_with_apple_platform_interface] - sky_engine 0.0.99 - sliver_tools 0.2.12 [flutter] - source_map_stack_trace 2.1.1 [path source_maps stack_trace] - source_maps 0.10.12 [source_span] - source_span 1.10.0 [collection path term_glyph] - sprintf 7.0.0 - sqflite 2.3.2 [flutter sqflite_common path] - sqflite_common 2.5.3 [synchronized path meta] - stack_trace 1.11.1 [path] - stream_channel 2.1.2 [async] - string_scanner 1.2.0 [source_span] - synchronized 3.1.0+1 - term_glyph 1.2.1 - test_api 0.7.0 [async boolean_selector collection meta source_span stack_trace stream_channel string_scanner term_glyph] - test_core 0.6.0 [analyzer args async boolean_selector collection coverage frontend_server_client glob io meta package_config path pool source_map_stack_trace source_maps source_span stack_trace stream_channel test_api vm_service yaml] - tuple 2.0.2 - typed_data 1.3.2 [collection] - universal_io 2.2.2 [collection meta typed_data] - url_launcher_android 6.3.0 [flutter url_launcher_platform_interface] - url_launcher_ios 6.2.5 [flutter url_launcher_platform_interface] - url_launcher_linux 3.1.1 [flutter url_launcher_platform_interface] - url_launcher_macos 3.1.0 [flutter url_launcher_platform_interface] - url_launcher_platform_interface 2.3.2 [flutter plugin_platform_interface] - url_launcher_web 2.3.0 [flutter flutter_web_plugins url_launcher_platform_interface web] - url_launcher_windows 3.1.1 [flutter url_launcher_platform_interface] - vector_graphics 1.1.11+1 [flutter http vector_graphics_codec] - vector_graphics_codec 1.1.11+1 - vector_graphics_compiler 1.1.11+1 [args meta path_parsing xml vector_graphics_codec path] - vector_math 2.1.4 - video_player_android 2.4.12 [flutter video_player_platform_interface] - video_player_avfoundation 2.5.6 [flutter video_player_platform_interface] - video_player_platform_interface 6.2.2 [flutter plugin_platform_interface] - video_player_web 2.3.0 [flutter flutter_web_plugins video_player_platform_interface web] - vm_service 14.2.1 - watcher 1.1.0 [async path] - web 0.5.1 - web_socket_channel 2.4.4 [async crypto stream_channel web] - webkit_inspection_protocol 1.2.1 [logging] - webview_flutter 4.7.0 [flutter webview_flutter_android webview_flutter_platform_interface webview_flutter_wkwebview] - webview_flutter_android 3.16.0 [flutter webview_flutter_platform_interface] - webview_flutter_platform_interface 2.10.0 [flutter meta plugin_platform_interface] - webview_flutter_wkwebview 3.13.0 [flutter path webview_flutter_platform_interface] - win32 5.3.0 [ffi] - xdg_directories 1.0.4 [meta path] - xml 6.5.0 [collection meta petitparser] - yaml 3.1.2 [collection source_span string_scanner] xxxxxxxx-7371638:~/xxxxxxxxx{main}$ ```

Additional context and comments

The Firebase Emulator is accessible from a Flutter app but not through a browser due to CORS policy. Is there any workaround or solution to configure CORS settings for Firebase Emulator in this environment?

firebase / flutterfire