How to fix HttpException: Connection closed before full header was received

Question

I have recently upgraded my flutter version in my app. But when I want to debug the application, it shows me the following error.

Error connecting to the service protocol: HttpException: Connection closed before full header was received, URI = http://127.0.0.1:50795/ws

Is there anyone facing the same issue after upgrading the flutter version? If is there any workaround, please share.

Answer 1

Right now this issue is opened on github https://github.com/flutter/flutter/issues/32587

Temporarily you can solve this issue by switching to physical device instead of emulator How to test android apps in a real device with Android Studio?

Decision found on github (link upward)

I've got a temporary work around, which I can use for now. The exception above is thrown when I run the emulator as a Pixel 3 Android 9.+ Target (Q API). I made up a second emulated device, a Pixel 2 Android 9.0 Target (28 API), and this target works fine.

I'm also noticing that the Pixel 2 target takes up 8.5GB on Disk, while the Pixel 3 target only takes up 1.4GB. It makes me wonder if the Pixel 3 target is missing some important things.

Answer 2

The issue is mainly with Android Q.

You can downgrade your android version from Android Q to Android Pie.

which eventually leads to resolve the issue.

Answer 3

No solution unless the Flutter guys fix it.

I'm having it on one machine (Mac OS Mojave) even when connecting physical iOS devices. Of course it happens too with emulated Android devices (no matter which one).

I've also having this problem in a different computer (MacOS Mojave too) with a physical Android device (with a very old Android version: 5.1).

flutter clean does not fix it at all in my case(s).

Answer 4

First turning off your WiFi/Bluetooth.

And run below command:

flutter clean

And then quitting or restarting your emulator.

Answer 5

In my case (error "HttpException: Connection closed before full header was received") the call was to an https address using Microsoft Internet Information Services as backend, in the SSL settings of the website in IIS i had mistakenly set "Client certificates: Accept" instead of "Client certificates: Ignore", setting "Ignore" solved the problem.

Answer 6

I've faced the same problem. Actually the problem was in the native code.

You can track the problem for android if you open an your_app/android project from Android Studio and run it, the same for iOS -> open ios project in XCode So after I've fixed it the app run as intended

I hope this'd help

Answer 7

I fixed the issue by setting request.persistentConnection = false; (default is true)

Writing this in case someone has the same problem...

Answer 8

Like Vitaly says ..

I am also struggling to force this error at all when building through Xcode for iOS and I imagine the same goes for Android with Android studio..

For iOS do flutter build ios --release and then open/run the project in Xcode

For Android do flutter build apk --release and then open/run the project in Android Studio

It seems to be an issue when debugging through flutter ... I will update this answer if I find otherwise but it seems stable with this method

Answer 9

I figured out how to limit the connections on the underlying HttpClient of NetworkImage!

I globally overrode the HttpClient: (ref: Override HttpClient globally)

class MyHttpOverrides extends HttpOverrides {
  @override
  HttpClient createHttpClient(SecurityContext context) {
    return super.createHttpClient(context)
        ..maxConnectionsPerHost = 5;
  }
}


void main() {
  HttpOverrides.global = MyHttpOverrides();
  runApp(MyApp());
}

Ref : Connection closed...

Answer 10

I got the same error when I using Flutter with http package.

import 'package:http/http.dart' as http;
...
http.Response response =  http.get('url')

This was fine. But when I went to get the response.statusCode, it Error connecting error.

I found that I'm using SSR/v2Ray on my pc. I fix it by setting the proxy on Android Emulator extended controls panel.

Answer 11

I was getting the same issue in POST request while sending the Images as multipart
Resolved by using 
contentType: MediaType('image', 'jpeg') in the http.MultipartFile function 
e.g 
    request.files.add(
          http.MultipartFile(
            'image',
            stream,
            length,
            filename: basename(_image1.path),
            contentType: MediaType('image', 'jpeg'),
          ),
        );
where 'image' is the paramter name.
 
Don't forget to import 'package:http_parser/http_parser.dart';
for MediaType.
 
Other Mediatype which you can use are 
"image/png"
"image/jpg" 
"image/jpeg"
And I am sending this too in Header "Content-Type": "multipart/form-data"

Answer 12

This was my Problem And this worked For me:

PROBLEM
App would crash abruptly out of no where

CAUSE
I was using cached_network_image, When users uploaded heavy photos > 2MB, cache ran out of memory then app crashes. No warning.

SOLUTION
Use FadeInImage.memoryNetwork() or something else like NetworkImage() but not cache_network_image, it only works for less than 2 MB photos
thanks :)

Answer 13

If you faced this issue on IOS build, follow th below steps

Goto Runner -> editSchema -> Run -> change build configurations to Debug.

if you are in Release mode you will face this issue, while running on android studio.

Answer 14

I found the solution/work around. For me, it worked on physical device but not on emulator. The simple fix is to use your an emulator of x86 environment rather than x86_64 emulator.