pg8000.exceptions.InterfaceError: Can't create a connection to host pgm-bp1p68c041qp48r6fo.pg.rds.aliyuncs.com and port 5432 (timeout is None and source_address is None).

[jlij]

The error generated after running the 'briefcase run web' command， can run normally with the same code under both the 'briefcase dev' and 'briefcase run android' commands.

Traceback (most recent call last):
  File "/lib/python3.11/site-packages/pg8000/core.py", line 206, in _make_socket
    sock = socket.create_connection((host, port), timeout, source_address)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python311.zip/socket.py", line 851, in create_connection
    raise exceptions[0]
  File "/lib/python311.zip/socket.py", line 836, in create_connection
    sock.connect(sa)
BlockingIOError: [Errno 26] Operation in progress

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/pyodide/pyscript/_internal.py", line 104, in run_pyscript
    result = eval_code(code, globals=__main__.__dict__)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python311.zip/_pyodide/_base.py", line 468, in eval_code
    .run(globals, locals)
     ^^^^^^^^^^^^^^^^^^^^
  File "/lib/python311.zip/_pyodide/_base.py", line 310, in run
    coroutine = eval(self.code, globals, locals)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<exec>", line 2, in <module>
  File "<frozen runpy>", line 226, in run_module
  File "<frozen runpy>", line 98, in _run_module_code
  File "<frozen runpy>", line 88, in _run_code
  File "/lib/python3.11/site-packages/flow/__main__.py", line 4, in <module>
    main().main_loop()
  File "/lib/python3.11/site-packages/toga/app.py", line 619, in main_loop
    self._impl.main_loop()
  File "/lib/python3.11/site-packages/toga_web/app.py", line 153, in main_loop
    self.create()
  File "/lib/python3.11/site-packages/toga_web/app.py", line 45, in create
    self.interface._startup()
  File "/lib/python3.11/site-packages/toga/app.py", line 641, in _startup
    self.startup()
  File "/lib/python3.11/site-packages/flow/app.py", line 172, in startup
    self.select_data = self.select_data()
                       ^^^^^^^^^^^^^^^^^^
  File "/lib/python3.11/site-packages/flow/app.py", line 151, in select_data
    connect = self.connect_db()
              ^^^^^^^^^^^^^^^^^
  File "/lib/python3.11/site-packages/flow/app.py", line 243, in connect_db
    return pg8000.connect(host='pgm-bp1p68c041qp48r6fo.pg.rds.aliyuncs.com'
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/lib/python3.11/site-packages/pg8000/__init__.py", line 111, in connect
    return Connection(
           ^^^^^^^^^^^
  File "/lib/python3.11/site-packages/pg8000/legacy.py", line 443, in __init__
    super().__init__(*args, **kwargs)
  File "/lib/python3.11/site-packages/pg8000/core.py", line 320, in __init__
    self.channel_binding, self._usock = _make_socket(
                                        ^^^^^^^^^^^^^
  File "/lib/python3.11/site-packages/pg8000/core.py", line 208, in _make_socket
    raise InterfaceError(
pg8000.exceptions.InterfaceError: Can't create a connection to host pgm-bp1p68c041qp48r6fo.pg.rds.aliyuncs.com and port 5432 (timeout is None and source_address is None).

[rmartin16]

Briefcase leverages Pyscript as the platform to run Python in the browser. As such, it cannot open sockets due to the security model of the browser. Therefore, most (if not all) packages for Python that need to open a socket are not compatible with Pyscript currently. Pyscript does provide some basic APIs for HTTP requests and WebSockets....but it's non-trivial to see how these could facilitate a database connection today.