macOS: no running event loop

[andypiper]

Same as #21 I think...

Browser shows an error:

bluetoothProblemHandler@http://127.0.0.1:8095/main.js:677:20
{
    "name": "Exception",
    "details": "no running event loop"
}

Console shows:

cat-printer python3 ./server.py
Serving at http://127.0.0.1:8095/
----------------------------------------
Exception occurred during processing of request from ('127.0.0.1', 64391)
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 316, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 347, in process_request
    self.finish_request(request, client_address)
  File "/Users/andypiper/Downloads/cat-printer/./server.py", line 276, in finish_request
    self.handler.__init__(request, client_address, self)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 747, in __init__
    self.handle()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/http/server.py", line 425, in handle
    self.handle_one_request()
  File "/Users/andypiper/Downloads/cat-printer/./server.py", line 82, in handle_one_request
    super().handle_one_request()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/http/server.py", line 413, in handle_one_request
    method()
  File "/Users/andypiper/Downloads/cat-printer/./server.py", line 229, in do_POST
    self.handle_api()
  File "/Users/andypiper/Downloads/cat-printer/./server.py", line 190, in handle_api
    } for device in self.printer.scan()]
  File "/Users/andypiper/Downloads/cat-printer/printer.py", line 367, in scan
    scanner = BleakScanner()
  File "/Users/andypiper/Downloads/cat-printer/bleak/backends/corebluetooth/scanner.py", line 44, in __init__
    self._manager = CentralManagerDelegate.alloc().init()
  File "/Users/andypiper/Downloads/cat-printer/bleak/backends/corebluetooth/CentralManagerDelegate.py", line 61, in init
    self.event_loop = asyncio.get_running_loop()
RuntimeError: no running event loop
----------------------------------------
Exception ignored in: <CentralManagerDelegate objective-c instance 0x0>
Traceback (most recent call last):
  File "/Users/andypiper/Downloads/cat-printer/bleak/backends/corebluetooth/CentralManagerDelegate.py", line 102, in __del__
    self.central_manager.removeObserver_forKeyPath_(self, "isScanning")
AttributeError: 'CentralManagerDelegate' object has no attribute 'central_manager'
Exception ignored in: <function CentralManagerDelegate.__del__ at 0x106626670>

I've tried toggling Bluetooth off and on, but this still happens.

I do not get prompted to allow the server program access to Bluetooth, which is weird - I would expect this.

[andypiper]

If it helps, this code works fine, but it invokes BleakScanner with a filter directly rather than setting up a scanner object first, I don't know if this might affect the functionality.

I tried python3 ./printer.py and it also crashes with a similar result:

Cat Printer
Connecting
Traceback (most recent call last):
  File "/Users/andypiper/Downloads/cat-printer/./printer.py", line 716, in <module>
    main()
  File "/Users/andypiper/Downloads/cat-printer/./printer.py", line 696, in main
    _main()
  File "/Users/andypiper/Downloads/cat-printer/./printer.py", line 653, in _main
    printer.scan(identifier, use_result=True)
  File "/Users/andypiper/Downloads/cat-printer/./printer.py", line 367, in scan
    scanner = BleakScanner()
  File "/Users/andypiper/Downloads/cat-printer/bleak/backends/corebluetooth/scanner.py", line 44, in __init__
    self._manager = CentralManagerDelegate.alloc().init()
  File "/Users/andypiper/Downloads/cat-printer/bleak/backends/corebluetooth/CentralManagerDelegate.py", line 61, in init
    self.event_loop = asyncio.get_running_loop()
RuntimeError: no running event loop
Exception ignored in: <CentralManagerDelegate objective-c instance 0x0>
Traceback (most recent call last):
  File "/Users/andypiper/Downloads/cat-printer/bleak/backends/corebluetooth/CentralManagerDelegate.py", line 102, in __del__
    self.central_manager.removeObserver_forKeyPath_(self, "isScanning")
AttributeError: 'CentralManagerDelegate' object has no attribute 'central_manager'
Exception ignored in: <function CentralManagerDelegate.__del__ at 0x10745e3a0>

[NaitLee]

Hi, In newest repo state, I switched discover method to something similar as rbaron/catprinter, please test if it will work, by simply cloning the repo & run it. (in your case, you've already installed the deps so you can directly start)

I can't test those myself, 'cause I have no Mac... And (hopefully) the event-loop RuntimeError won't show, since it's just non-sense (event loop just dies when there's an (worth-to-spot) unhandled exception inside)

[andypiper]

It works sometimes, now. When I Refresh and scan for devices, sometimes there is an error on a particular (non-printer) device and it stops and the (GB03) printer is not in the list, but if I try again one or more times, it shows up, and then I can print. The drop-down list is showing a lot of different BLE devices as well as the printer, so I guess something is causing an error in the scan handling.

[andypiper]

Success 😸

[NaitLee]

Ouch! I forgot to filter non-printer devices again (first time is around 0.2.0) That's easy to fix. But I'm interested on what's the error, when being fuzzed by unrelated devices? I think we could have a workaround to avoid that.

That's enough to publish a new release :)

[andypiper]

Sure, so here is an example. Server says:

Exception occurred during processing of request from ('127.0.0.1', 53615)
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 316, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 347, in process_request
    self.finish_request(request, client_address)
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 308, in finish_request
    self.handler.__init__(request, client_address, self)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 747, in __init__
    self.handle()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/http/server.py", line 425, in handle
    self.handle_one_request()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 90, in handle_one_request
    super().handle_one_request()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/http/server.py", line 413, in handle_one_request
    method()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 251, in do_POST
    self.handle_api()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 225, in handle_api
    self.update_printer()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 194, in update_printer
    self.printer.connect(name, address)
  File "/Users/andypiper/Development/third-party/Cat-Printer/printer.py", line 333, in connect
    self.model = Models[name]
KeyError: 'Living Room AppleTV'

BTW I cannot copy/paste from the error section on the web UI, this is really inconvenient for bug reporting! But it lists the AppleTV device in the error message.

Second time I scanned, it got stuck on a device Withings Aura 80, and finally a third time, on Unknown... by this time, my printer (GB03) shows in the list so I can select it.

Exception occurred during processing of request from ('127.0.0.1', 53830)
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 316, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 347, in process_request
    self.finish_request(request, client_address)
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 308, in finish_request
    self.handler.__init__(request, client_address, self)
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/socketserver.py", line 747, in __init__
    self.handle()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/http/server.py", line 425, in handle
    self.handle_one_request()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 90, in handle_one_request
    super().handle_one_request()
  File "/opt/homebrew/Cellar/python@3.9/3.9.12/Frameworks/Python.framework/Versions/3.9/lib/python3.9/http/server.py", line 413, in handle_one_request
    method()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 251, in do_POST
    self.handle_api()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 225, in handle_api
    self.update_printer()
  File "/Users/andypiper/Development/third-party/Cat-Printer/./server.py", line 194, in update_printer
    self.printer.connect(name, address)
  File "/Users/andypiper/Development/third-party/Cat-Printer/printer.py", line 333, in connect
    self.model = Models[name]
KeyError: 'Unknown'
----------------------------------------

So I wondered if it might be devices with spaces in the name? Or if you can be more specific about which device(s) to search for...

[NaitLee]

Oh sorry the sole problem is didn't filtering non-printer devices.

Only last commit have this problem, i.e. fix for macOS I will take care very soon. Thank you very much!

And, tip about looking at error message:

    self.model = Models[name]
KeyError: 'Living Room AppleTV'

As you see, this just means AppleTV wasn't found as a printer model and that's it.

[NaitLee]

Please try the newest 0.4.2. I'm in a hurry and didn't fix frontend error copying (it's matter of CSS).

[andypiper]

Yes, this is better! It now just looks for the printer and (usually) finds it, but sometimes it finds it and then gets an error (but the app still works).

Error: API Failure
    at http://127.0.0.1:8095/~every.js:691:28
    at async callApi (http://127.0.0.1:8095/~every.js:680:12)
    at async Main.set (http://127.0.0.1:8095/~every.js:1097:35)
{
    "name": "BleakError",
    "details": "Device with address B4BE32FB-7707-0593-CE92-E29B52E3E7E3 was not found"
}

[NaitLee]

Maybe it's Mac assigning another uuid after scanning. but I'm assuming it won't change. I'll try fix

[NaitLee]

Now the previous scanning result (of printers) won't persist to next page refresh. It also solves another problem I've seen. Try newest commit

[NaitLee]

I think it's solved, let me close :)