Unobtrusive Method for Instantiating Socket Object from File Descriptor

Question

There currently exists a socket library in Python:

Reference: http://docs.python.org/library/socket.html

However, this library does not include functionality for referencing an existing socket based off a file descriptor. I am currently developing Python bindings for a C++ library which opens up a socket first and need a way to reference this opened socket in Python after-the-fact. Keep in mind that this is on Windows (I am using a cross-platform layer of abstraction which neglects file handles).

The code is similar to this:

fd = connect(...) # file descriptor
os.read(fd, buffer)
os.close(fd)

I am looking to find a way to actually define a socket object based off the file descriptor without the by-value duplication found in os.dup and os.dup2.

Would anyone know a way to reference this?

Answer 1

As it doesn't appear that this question has been answered as of yet (for 1 week), I'll state my solution.

I implemented an internal binding for retrieving the socket information from within the library, converting the ctypes to pytuples. Because the application itself is wrapped in py2exe, this modification is unobtrusive to the end-user.

Answer 2

socket.fromfd(fd, family, type[, proto]) seems to do what you want. It's only available on Unix like platforms, unfortunately.

Unfortunately, this functionality does not seem to be available for Windows. You may consider logging a bug at http://bugs.python.org/ (I see no reason why a windows socket object should not be wrappable in a Python socket object).

Answer 3

Does this help? You can use it to wrap sockets and/or file descriptors, so that they feel more like files, while providing operations useful in framing data like sock.readto('\0'):

http://stromberg.dnsalias.org/~strombrg/bufsock.html

Answer 4

Please check again:

http://docs.python.org/library/socket.html#socket.fromfd