Error: Unsupported operation: RawSocket constructor

[Patrick386]

I use Google Workspace and have an account.
Also, I'm using the FlutterFire UI.

I got the mail and token normally.
An error occurred as below.
Could you please tell me what settings I need?

Flutter Web
Error: Unsupported operation: RawSocket constructor

Code:

  sendEmail(UserModel prontoUser) async {
    final String userEmail =  'milke.${prontoUser.email}';     
    final String accessToken = prontoUser.accessToken;

    final smtpServer = gmailSaslXoauth2(userEmail, accessToken);

    print('email:${userEmail}  - ${accessToken}');
    final message = Message()
      ..from = Address(userEmail, 'Pronto Io')
      ..recipients = [userEmail]
      ..subject = 'Hello ellisvill'
      ..text = 'This is a test email!';

    print('message:$userEmail  ${accessToken}');

    await send(message, smtpServer);

    ToastMsg(message: 'Success Send email!', msgType: MsgType.success);
  }

message:milke.patrick386@sint.kr  eyJhbGciOiJSU......

Error: Unsupported operation: RawSocket constructor
    at Object.throw_ [as throw] (http://localhost:51944/dart_sdk.js:5067:11)
    at Function.connect (http://localhost:51944/dart_sdk.js:60281:17)
    at Function.connect (http://localhost:51944/dart_sdk.js:58470:27)
    at Function.connect (http://localhost:51944/dart_sdk.js:58362:33)
    at connection.Connection.new.connect (http://localhost:51944/packages/mailer/src/smtp/connection.dart.lib.js:176:50)
    at connect.next (<anonymous>)
    at runBody (http://localhost:51944/dart_sdk.js:40590:34)
    at Object._async [as async] (http://localhost:51944/dart_sdk.js:40621:7)
    at connection.Connection.new.connect (http://localhost:51944/packages/mailer/src/smtp/connection.dart.lib.js:172:20)
    at connect (http://localhost:51944/packages/mailer/src/smtp/smtp_client.dart.lib.js:108:17)
    at connect.next (<anonymous>)
    at runBody (http://localhost:51944/dart_sdk.js:40590:34)
    at Object._async [as async] (http://localhost:51944/dart_sdk.js:40621:7)
    at Object.connect (http://localhost:51944/packages/mailer/src/smtp/smtp_client.dart.lib.js:105:18)
    at send (http://localhost:51944/packages/mailer/src/smtp/mail_sender.dart.lib.js:164:43)
    at send.next (<anonymous>)
    at runBody (http://localhost:51944/dart_sdk.js:40590:34)
    at Object._async [as async] (http://localhost:51944/dart_sdk.js:40621:7)
    at Object.send (http://localhost:51944/packages/mailer/src/smtp/mail_sender.dart.lib.js:162:18)
    at sendEmail (http://localhost:51944/packages/pronto/pages/product_page/product_detail_screen.dart.lib.js:46073:27)
    at sendEmail.next (<anonymous>)
    at runBody (http://localhost:51944/dart_sdk.js:40590:34)
    at Object._async [as async] (http://localhost:51944/dart_sdk.js:40621:7)
    at dashboard_screen$._EmailSender.new.sendEmail (http://localhost:51944/packages/pronto/pages/product_page/product_detail_screen.dart.lib.js:46059:20)
    at dashboard_screen$._EmailSender.new.<anonymous> (http://localhost:51944/packages/pronto/pages/product_page/product_detail_screen.dart.lib.js:46055:36)
    at Generator.next (<anonymous>)
    at runBody (http://localhost:51944/dart_sdk.js:40590:34)
    at Object._async [as async] (http://localhost:51944/dart_sdk.js:40621:7)
    at http://localhost:51944/packages/pronto/pages/product_page/product_detail_screen.dart.lib.js:46054:575
    at ink_well._InkResponseState.new.[_handleTap] (http://localhost:51944/packages/flutter/src/material/icon_button.dart.lib.js:40468:31)
    at tap.TapGestureRecognizer.new.invokeCallback (http://localhost:51944/packages/flutter/src/gestures/recognizer.dart.lib.js:190:18)
    at tap.TapGestureRecognizer.new.handleTapUp (http://localhost:51944/packages/flutter/src/gestures/tap.dart.lib.js:409:40)
    at tap.TapGestureRecognizer.new.[_checkUp] (http://localhost:51944/packages/flutter/src/gestures/tap.dart.lib.js:217:12)
    at tap.TapGestureRecognizer.new.handlePrimaryPointer (http://localhost:51944/packages/flutter/src/gestures/tap.dart.lib.js:166:23)
    at tap.TapGestureRecognizer.new.handleEvent (http://localhost:51944/packages/flutter/src/gestures/recognizer.dart.lib.js:426:16)
    at pointer_router.PointerRouter.new.[_dispatch] (http://localhost:51944/packages/flutter/src/gestures/pointer_router.dart.lib.js:86:9)
    at http://localhost:51944/packages/flutter/src/gestures/pointer_router.dart.lib.js:112:26
    at LinkedMap.new.forEach (http://localhost:51944/dart_sdk.js:27679:11)
    at pointer_router.PointerRouter.new.[_dispatchEventToRoutes] (http://localhost:51944/packages/flutter/src/gestures/pointer_router.dart.lib.js:110:29)
    at pointer_router.PointerRouter.new.route (http://localhost:51944/packages/flutter/src/gestures/pointer_router.dart.lib.js:105:37)
    at binding$5.WidgetsFlutterBinding.new.handleEvent (http://localhost:51944/packages/flutter/src/gestures/binding.dart.lib.js:364:26)
    at binding$5.WidgetsFlutterBinding.new.dispatchEvent (http://localhost:51944/packages/flutter/src/gestures/binding.dart.lib.js:352:24)
    at binding$5.WidgetsFlutterBinding.new.dispatchEvent (http://localhost:51944/packages/flutter/src/rendering/layer.dart.lib.js:5427:13)
    at binding$5.WidgetsFlutterBinding.new.[_handlePointerEventImmediately] (http://localhost:51944/packages/flutter/src/gestures/binding.dart.lib.js:328:14)
    at binding$5.WidgetsFlutterBinding.new.handlePointerEvent (http://localhost:51944/packages/flutter/src/gestures/binding.dart.lib.js:302:43)
    at binding$5.WidgetsFlutterBinding.new.[_flushPointerEventQueue] (http://localhost:51944/packages/flutter/src/gestures/binding.dart.lib.js:292:14)
    at binding$5.WidgetsFlutterBinding.new.[_handlePointerDataPacket] (http://localhost:51944/packages/flutter/src/gestures/binding.dart.lib.js:283:54)
    at Object.invoke1 (http://localhost:51944/dart_sdk.js:190401:7)
    at _engine.EnginePlatformDispatcher.__.invokeOnPointerDataPacket (http://localhost:51944/dart_sdk.js:171080:15)
    at _engine.PointerBinding.__.[_onPointerData] (http://localhost:51944/dart_sdk.js:171962:49)
    at http://localhost:51944/dart_sdk.js:172400:28
    at http://localhost:51944/dart_sdk.js:172356:16
    at loggedHandler (http://localhost:51944/dart_sdk.js:172061:11)

[close2]

This library doesn't work in flutter web.
A browser simply doesn't allow you to open raw sockets. You can only open http connections from inside a browser.

[nuno84]

Hi, this also applies to an edge-function env, correct? I am experiencing the same error.
Any alternative for it?
Thanks

[close2]

@nuno84 Not allowing smtp connections in edge environments is not because of technical reasons.
Your provider might not allow them to prevent spam,...

If the usual ports are blocked you might try to find a provider which exposes its smtp service on an unusal port.

Another workaround (which would also be a good solution for flutter web based applications) is to use for instance supabase: trigger a transactional mail whenever you write into a specific database (unless supabase doesn't allow this in their terms and conditions...)

If you find another mail service which allows sending mails through an http API please add it to this comment.