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!

Arslan ud Din Shafiq · Accepted Answer · 2024-05-24 20:20:54Z

17

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

edited May 24, 2024 at 20:20

answered Feb 8, 2020 at 14:14

Arslan ud Din Shafiq

3403 silver badges12 bronze badges

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2 Comments

Nicholas Obert Over a year ago

Well.. this is a really dumb error, but it actually happens a lot

Edoardo Over a year ago

...and from other galaxies you get here cause you sometimes forget that qemu / simulators is not localhost ':)

user13065506user13065506 · Accepted Answer · 2020-10-13 02:10:01Z

17

If you use the emulator with localhost. please change the IP address from 127.0.0.1 to 10.0.2.2 in API urls.

answered Oct 13, 2020 at 2:10

user13065506

Comments

Vanni Buglione · Accepted Answer · 2020-12-24 21:21:09Z

to avoid the following problems:

write failed
connection closed before ...
Flutter Doctor Error - SocketException: Write failed (OS Error: Broken pipe, errno = 32)

you need to add the correct parameters in the headers.

In my case these problems occur with uploading images and sending base64 encoded requests. I solved it by adding the following 'connection' header: 'keep-alive',

  final response = await this.httpClient.put(
    url,
    encoding: Utf8Codec(),
    headers: <String, String>{
      'Content-Type': 'application/json; charset=UTF-8',
      'Accept': "*/*",
      'connection': 'keep-alive',
      'Accept-Encoding' : 'gzip, deflate, br',
    },
    body: body,
  );

it works for me

mgnl · Accepted Answer · 2021-05-31 08:00:31Z

1

I had the same problem. I've connencted my PC to my Phone hotspot, got my ip adress using "ipconfig" and made it as my base URL like this

"http://PC_IP_Adress:8000/api"

answered May 31, 2021 at 8:00

mgnl

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