Error connecting to the service protocol: HttpException: Connection closed before full header was received, uri = http://127.0.0.1:8100/ws

[sahil311289]

Have been stuck for days on this. iOS app crashes on launch.

Launching lib/main.dart on Sahil’s iPhone in debug mode...
Automatically signing iOS for device deployment using specified development team in Xcode project: Q48Y4UFKL8
Starting Xcode build...
Xcode build done.
Installing and launching...
5.4.0 - [Firebase/Analytics][I-ACS023007] Firebase Analytics v.50001000 started
5.4.0 - [Firebase/Analytics][I-ACS023008] To enable debug logging set the following application argument: -FIRAnalyticsDebugEnabled (see http://goo.gl/RfcP7r)
Error connecting to the service protocol: HttpException: Connection closed before full header was received, uri = http://127.0.0.1:8100/ws

Flutter doctor:

Running flutter doctor...
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v0.5.1, on Mac OS X 10.13.5 17F77, locale en-IN)
[!] Android toolchain - develop for Android devices (Android SDK 28.0.0-rc1)
    ✗ Android license status unknown.
[✓] iOS toolchain - develop for iOS devices (Xcode 9.4.1)
[✓] Android Studio (version 3.1)
[✓] IntelliJ IDEA Community Edition (version 2018.1.5)
[✓] VS Code (version 1.23.1)
[✓] Connected devices (2 available)

! Doctor found issues in 1 category.
Process finished with exit code 0

[zoechi]

Looks similar to #18973
Are you using any kind of proxy?

[sahil311289]

Yeah, it is the same issue.
Nope, no proxy.

[zoechi]

There is also #14991

I haven't figured out why @Hixie concluded that it is an emulator issue (see #12353 (comment))

If this is actually related you could try #13379 (comment)

[DanTup]

What happens after you get that line in the terminal? Does it quit, or stay hung?

If you take the /ws off the end of the url in the error (eg. http://127.0.0.1:8100/) and paste it into your browser, does anything load?

[zipzit]

I'm having the exact same issue. I'm working on https://github.com/nitishk72/flutter_image_picker . I can test the software program successfully on Xcode ios simulator just fine in file picker mode. Obviously the emulator has no access to the camera. Hence the use of a real iphone device. I paid my subscription to Apple, I registered the device via Xcode, etc...

While testing for this posting, I went back to basics. I create a new hello_world (the count increment example). Sample ran great... once. Then I added a single character to the line home: new MyHomePage(title: 'Flutter Demo2 Home Page'),, something that I could see upon reload. Continuous failure from that moment on.

Launching lib/main.dart on iPhone in debug mode...
Signing iOS app for device deployment using developer identity: "iPhone Developer: (my name) (X99999999999)"
Xcode build done.
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/local/Cellar/python@2/2.7.15/Frameworks/Python.framework/Versions/2.7/lib/python2.7/copy.py", line 52, in <module>
    import weakref
  File "/usr/local/Cellar/python@2/2.7.15/Frameworks/Python.framework/Versions/2.7/lib/python2.7/weakref.py", line 14, in <module>
    from _weakref import (
ImportError: cannot import name _remove_dead_weakref
Error connecting to the service protocol: HttpException: , uri = http://127.0.0.1:8110/ws
Exited (sigterm)

Note: the port numbers start at 8101 and vary depending on the run... I tested with the browser multiple times, but was never able get an IP address response, no matter which port number.

$ flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel beta, v0.5.1, on Mac OS X 10.13.5 17F77, locale en-US)
[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
[✓] iOS toolchain - develop for iOS devices (Xcode 9.4.1)
[✓] Android Studio (version 3.1)
[!] VS Code (version 1.24.1)
[✓] Connected devices (1 available)

! Doctor found issues in 1 category.

(not sure what's up with the VS code error... I've installed, removed and reinstalled that thing multiple times. )

[!] VS Code (version 1.24.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension not installed; install from
      https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

Clearly the VS code is showing the flutter-dart module.

OS: System Version: macOS 10.13.5 (17F77)
iphone: 6S, ios = 11.3.1 (15E302)
Xcode: Version 9.4.1 (9F2000)
VS Code: Version 1.24.1 (1.24.1)

I'm going to reboot the computer and try this all again. I wanted to get this submitted before the reboot.

[zipzit]

Still testing. ios software emulator works great. Real physical device iphone = erratic and just odd. When I push code to the physical device, it seems to open up the app and I get a totally white screen. Quick close the app (with home button push), re-open = same fail (all white screen) . I still see the exact same error message in VS code during this push process.

Remove the app 'thread" (with double home button push and then slide the white screen app up and off the phone), then re-click the icon on the physical device = success. The simple increment app works, but its not clear what's going on here. I haven't yet tested my simple camera app with the same test.

Thanks to all for assistance. One testing note: I did look at the iphone console... holy cow but there are a whole of messages going by, even on a phone sitting at idle. The physical device (an iphone 6S) console and device logs are available via Xcode --> Window --> Devices and Simulators --> choose Devices, then select either "view device logs" or "Open Console" button. With phone at idle on the desk, black screen on display, I'm seeing nearly 1200 messages / minute. Ugh. Now I see where my battery juice is going....

Is there any testing that I can do to bring more clarity on this issue? Many thanks to all the folks supporting Flutter.

---Update: The camera image app had an error in camera permissions (which I would not have discovered had I not opened up the physical device console tool referenced above. ) issue fixed in code, and sure enough the camera app works, albeit after the clumsy code push to device. (push code, ignore the error messages, remove the 'thread' with double button push and slide up and off screen, then reopen the app), sigh.

[DanTup]

What happens if you run python -c "import weakref"? There's some info here suggesting maybe something wrong with the Python install.

(not sure what's up with the VS code error... I've installed, removed and reinstalled that thing multiple times. )

It's a bug; VS Code started lower-casing the extension folder names and our detection was accidentally case-sensitive. It's fixed in the master channel but hasn't made the beta channel yet.

[zipzit]

What happens if you run python -c "import weakref"? There's some info here suggesting maybe something wrong with the Python install.

@DanTup. I tried that. No response from the command line interpreter after $ python -c "import weakref" . I tried to do the whole push to physical device process with mods to code content. Still getting the entire ImportError: cannot import name _remove_dead_weakref error. I do notice the localhost port number keeps increasing.

It's a bug; VS Code started lower-casing the extension folder names and our detection was accidentally case-sensitive. It's fixed in the master channel but hasn't made the beta channel yet.

When you say master channel / beta channel are you talking about VS Code or about the flutter install? ( I didn't realize I had any beta tools loaded in either place...) .

Is there any other testing that would help bring more light to the weakref issue? Many thanks.

-----Update------------------------------------------------------------------------------------

Oops. I didn't see there was a link in your comment. When I research the link, the command they used was $aprun -n 1 python -c "import weakref" . I have no clue what aprun is. When I run that on the macOS I get -bash: aprun: command not found .

But wait, there's more! There was a link in that reference to https://askubuntu.com/questions/981663/python2-7-broken-by-weakref-import-error-please-help . The first answer in that link from user duhaime specifically addresses the fault on his Mac. His fix was

$ brew list

and if applicable

$ brew remove python@2 --ignore-dependencies

. I had to do that twice, but that fix has totally corrected all of my _remove_dead_weakref errors in my flutter application and code push to physical ios mobile device!

Yipee... This seems to be a python version management issue and not a flutter fault. (Note, I haven't yet tested all of my Python stuff, but we'll cross that bridge when we get to it...) . I will say I'm lost when it comes to managing all of the different python versions and symlinks, but there is a fix for that.

Is the action from askUbuntu good enough to close this issue? dunno. Its a place to start... My issue is fixed, but I wasn't there originator of this issue. Others are having the same troubles.

[DanTup]

The mis-reporting of the VS Code extension in flutter doctor is fixed in Flutter's master channel (it's flutter that reads the VS Code extensions). Probably it will be in the next beta release, but it's safe to ignore for now.

I'm not really sure about the Python issue - I hoped it would fail when you ran that so it was easier to debug, but it's strange that you can import it from a terminal like that but not when running flutter. Have you tried running flutter from the same terminal where Python worked, in case you've somehow got a different PATH there than when running from VS Code? (sometimes people have PATHs configured in shell scripts that only apply in the terminals, so VS Code often has different paths!).

[zipzit]

Oh, I have no idea what I'm doing when it comes to python symlinks and multiple different paths. Not sure you saw my last edit. I also didn't see how many open issues there are in this repo. I now understand the urgency in getting stuff closed. How can I help? What can I do next?

and thanks for the info on the flutter doctor stuff...

And yeah, I did futz up my python stuff.. If I run $ python --versionwithin VSCode terminal I get the response Python 2.7.10 If I run the same command in a systems shell I now get -bash: /usr/local/bin/python: No such file or directory So yeah, need to tread with care.

update: After re-installing python2 in system shell via $ brew install python2 the _remove_dead_weakref flutter code push error is back, sigh. There is one thing different now. Although I'm getting the errors in VSCode console, the actual app that pops up up the first time is fully functional, instead of just being a white screen. Not sure what's up with that.

[DanTup]

I didn't see your edit, sorry. Sounds like you've traded one problem for another!

I would start by doing echo $path in your terminal and in the VS Code terminal and seeing where they're different - presumably the difference is why it works in one and not the other (I'd also restart both your terminal and VS Code first).

I'm getting the errors in VSCode console

What sort of errors?

[zipzit]

This whole thing is just odd. I get no response at all to $ echo $path no matter where I run it. In a system bash window $ python --version results in Python 2.7.15, $ python2 --version = Python 2.7.15 and $ python3 --version = Python 3.6.5

In VS Code command line terminal the same tests gets slightly different results. $ python --version results in Python 2.7.10, $ python2 --version = Python 2.7.15 and $ python3 --version = Python 3.6.5

Could the _remove_dead_weakref issue be related to the difference between python 2.7.10 and 2.7.15?

When I push to physical device the error message within VS code debug console:

Launching lib/main.dart on iPhone in debug mode...
Signing iOS app for device deployment using developer identity: "iPhone Developer: MyName (X99999999)"
Xcode build done.
Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/copy.py", line 52, in <module>
    import weakref
  File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/weakref.py", line 14, in <module>
    from _weakref import (
ImportError: cannot import name _remove_dead_weakref
Error connecting to the service protocol: HttpException: , uri = http://127.0.0.1:8116/ws
Exited (sigterm)