Listening host string is not sent to uws properly

[wdhwg001]

Describe the bug

I tried to listen with a host 127.0.0.1 but it turns out that socketify is listening to 0.0.0.0 instead, and the callback is having a mostly empty, sometimes random string as its host.

Tested with int port number without host, dict and AppListenOptions.

Desktop (please complete the following information):

• Device: MacBook Pro M1 Max (arm64)
• OS: macOS 15.3
• Version 0.0.31
• CPython 3.12.8
• cffi Version 1.17.1, 1.17.0, 1.16.0

Additional context

I'm feeling that it'd be either we are not using cffi in the right way, or there's some issues with the latest cffi.

A minimal reproducible example is here:

Python 3.12.8 (main, Jan 30 2025, 09:29:57) [Clang 16.0.0 (clang-1600.0.26.6)]
Type 'copyright', 'credits' or 'license' for more information
IPython 8.32.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import cffi

In [2]: ffi = cffi.FFI()

In [3]: ffi.cdef("""
   ...: typedef struct
   ...: {
   ...:     int port;
   ...:     const char *host;
   ...:     int options;
   ...: } uws_app_listen_config_t;
   ...: """)

In [4]: native_options = ffi.new("uws_app_listen_config_t *")

In [5]: options = native_options[0]

In [6]: port = 3000

In [7]: host = "127.0.0.1"

In [8]: options.port = (
   ...:     ffi.cast("int", port)
   ...:     if isinstance(port, int)
   ...:     else ffi.cast("int", 0)
   ...: )

In [9]: options.port
Out[9]: 3000

In [10]: options.host = (
    ...:     ffi.new("char[]", host.encode("utf-8"))
    ...: )

In [11]: options.host
Out[11]: <cdata 'char *' 0x1259f6210>

In [12]: ffi.string(options.host).decode('utf-8')
Out[12]: ''

In [13]: foo = ffi.new("char[]", host.encode("utf-8"))

In [14]: foo
Out[14]: <cdata 'char[]' owning 10 bytes>

In [15]: options.host = foo

In [16]: options.host
Out[16]: <cdata 'char *' 0x145a34da0>

In [17]: ffi.string(options.host).decode('utf-8')
Out[17]: '127.0.0.1'

Linked to: python-cffi/cffi#155