Flutter Unhandled Exception: SocketException: OS Error: Connection refused, errno = 111

Question

I'm attempting to get a flutter app, made in android studio, to connect to a c# api hosted locally. Running the api on IIS Express gives a url of https://localhost:44364/api/trip, which I believe relates to http://10.0.2.2:44364/api in Android studio when using the emulator.

I'm attempting to retrieve a list of Trips from the db via API. Postman works fine.

I get multiple errors. I have tried the emulator, I've also tried plugging a phone in directly and switching the address to my ip address. I've even tried switching the api to run in the console and not IIS. Nothing works.

I did attempt to reach the api through the emulator browser and was told the site was unsafe, leading me to think it's a certificate problem.

The flutter project is fairly simple, it's in its infancy stage and I'm still learning how to program it.

Here are the three flutter files, and the error list.

main.dart

import 'dart:convert';
import 'package:bike_client/API.dart';
import 'package:bike_client/models/Trip.dart';
import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Track It',
      theme: new ThemeData(
        primarySwatch: Colors.red,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  createState() => new _MyHomePageState();
}

class _MyHomePageState extends State {
  var trips = new List<Trip>();

  _getTrips() {
    API.getTrips().then((response) {
      setState(() {
        Iterable list = json.decode(response.body);
        trips = list.map((model) => Trip.fromJson(model)).toList();
      });
    });
  }

  initState() {
    super.initState();
    _getTrips();
  }

  dispose() {
    super.dispose();
  }

  @override
  build(context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("Trip List"),
        ),
        body: ListView.builder(
          itemCount: trips.length,
          itemBuilder: (context, index) {
            return ListTile(title: Text((trips[index].tripId).toString()));
          },
        ));
  }
}

API.dart

import 'dart:async';
import 'package:http/http.dart' as http;

//const baseUrl = "https://192.168.1.14:44364/api";
const baseUrl = "http://10.0.2.2:44364/api";

class API {
  static Future getTrips() {
    var url = baseUrl + "/trip/1";
    return http.get(url);
  }
}

Trip.dart

class Trip {
  int tripId;
  int userId;

  Trip(int tripId, int userId) {
    this.tripId = tripId;
    this.userId = userId;
  }

  Trip.fromJson(Map json)
      : tripId = json['tripId'],
        userId = json['userId'];

  Map toJson() {
    return {'tripId': tripId, 'userId': userId};
  }
}

Console

Launching lib\main.dart on AOSP on IA Emulator in debug mode...
Running Gradle task 'assembleDebug'...
E/flutter ( 7781): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: SocketException: OS Error: Connection refused, errno = 111, address = localhost, port = 38612
E/flutter ( 7781): #0      IOClient.send (package:http/src/io_client.dart:33:24)
E/flutter ( 7781): <asynchronous suspension>
E/flutter ( 7781): #1      BaseClient._sendUnstreamed (package:http/src/base_client.dart:176:38)
E/flutter ( 7781): #2      BaseClient.get (package:http/src/base_client.dart:35:7)
E/flutter ( 7781): #3      get.<anonymous closure> (package:http/http.dart:46:36)
E/flutter ( 7781): #4      _withClient (package:http/http.dart:166:20)
E/flutter ( 7781): #5      get (package:http/http.dart:46:5)
E/flutter ( 7781): #6      API.getTrips (package:bike_client/API.dart:9:12)
E/flutter ( 7781): #7      _MyHomePageState._getTrips (package:bike_client/main.dart:30:9)
E/flutter ( 7781): #8      _MyHomePageState.initState (package:bike_client/main.dart:40:5)
E/flutter ( 7781): #9      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4355:58)
E/flutter ( 7781): #10     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #11     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #12     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #13     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #14     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #15     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #16     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #17     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #18     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #19     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #20     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #21     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #22     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #23     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #25     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #26     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #28     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #29     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #30     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #31     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
E/flutter ( 7781): #32     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #33     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #34     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #35     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #36     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #38     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #39     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #40     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #41     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #42     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #43     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #44     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
E/flutter ( 7781): #45     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #46     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #47     Element.updateChild (package:flutter/src/wid
E/flutter ( 7781): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: SocketException: OS Error: Connection refused, errno = 111, address = localhost, port = 38760
E/flutter ( 7781): #0      IOClient.send (package:http/src/io_client.dart:33:24)
E/flutter ( 7781): <asynchronous suspension>
E/flutter ( 7781): #1      BaseClient._sendUnstreamed (package:http/src/base_client.dart:176:38)
E/flutter ( 7781): #2      BaseClient.get (package:http/src/base_client.dart:35:7)
E/flutter ( 7781): #3      get.<anonymous closure> (package:http/http.dart:46:36)
E/flutter ( 7781): #4      _withClient (package:http/http.dart:166:20)
E/flutter ( 7781): #5      get (package:http/http.dart:46:5)
E/flutter ( 7781): #6      API.getTrips (package:bike_client/API.dart:9:12)
E/flutter ( 7781): #7      _MyHomePageState._getTrips (package:bike_client/main.dart:30:9)
E/flutter ( 7781): #8      _MyHomePageState.initState (package:bike_client/main.dart:40:5)
E/flutter ( 7781): #9      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4355:58)
E/flutter ( 7781): #10     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #11     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #12     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #13     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #14     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #15     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #16     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #17     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #18     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #19     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #20     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #21     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #22     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #23     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #25     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #26     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #28     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #29     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #30     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #31     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
E/flutter ( 7781): #32     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #33     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #34     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #35     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #36     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #38     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #39     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #40     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #41     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #42     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #43     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #44     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
E/flutter ( 7781): #45     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #46     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #47     Element.updateChild (package:flutter/src/wid
E/flutter ( 7781): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: SocketException: OS Error: Connection refused, errno = 111, address = localhost, port = 38884
E/flutter ( 7781): #0      IOClient.send (package:http/src/io_client.dart:33:24)
E/flutter ( 7781): <asynchronous suspension>
E/flutter ( 7781): #1      BaseClient._sendUnstreamed (package:http/src/base_client.dart:176:38)
E/flutter ( 7781): #2      BaseClient.get (package:http/src/base_client.dart:35:7)
E/flutter ( 7781): #3      get.<anonymous closure> (package:http/http.dart:46:36)
E/flutter ( 7781): #4      _withClient (package:http/http.dart:166:20)
E/flutter ( 7781): #5      get (package:http/http.dart:46:5)
E/flutter ( 7781): #6      API.getTrips (package:bike_client/API.dart:9:12)
E/flutter ( 7781): #7      _MyHomePageState._getTrips (package:bike_client/main.dart:30:9)
E/flutter ( 7781): #8      _MyHomePageState.initState (package:bike_client/main.dart:40:5)
E/flutter ( 7781): #9      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4355:58)
E/flutter ( 7781): #10     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #11     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #12     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #13     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #14     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #15     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #16     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #17     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #18     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #19     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #20     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #21     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #22     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #23     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #24     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #25     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #26     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #27     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #28     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #29     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #30     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #31     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
E/flutter ( 7781): #32     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #33     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #34     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #35     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #36     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #37     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #38     SingleChildRenderObjectElement.mount (package:flutter/src/widgets/framework.dart:5445:14)
E/flutter ( 7781): #39     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #40     Element.updateChild (package:flutter/src/widgets/framework.dart:2988:12)
E/flutter ( 7781): #41     ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4243:16)
E/flutter ( 7781): #42     Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
E/flutter ( 7781): #43     ComponentElement._firstBuild (package:flutter/src/widgets/framework.dart:4206:5)
E/flutter ( 7781): #44     StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4381:11)
E/flutter ( 7781): #45     ComponentElement.mount (package:flutter/src/widgets/framework.dart:4201:5)
E/flutter ( 7781): #46     Element.inflateWidget (package:flutter/src/widgets/framework.dart:3194:14)
E/flutter ( 7781): #47     Element.updateChild (package:flutter/src/wid
E/flutter ( 7781): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: SocketException: 
AND MUCH MORE!

Answer 1

This error occurs mostly when your android AVD or android device is not connected to internet. Sometimes, the developer tries to access plugin on localhost from android device instead of AVD, in such cases, same error occurs. I hope this solves your problem.

Other scenarios involves port blocked by firewalls on serverside.

Kindly upvote if you find my answer usable.

Learn Cybers