Now that we’ve seen how sockets figure into the Internet picture, let’s move on to explore the tools that Python provides for programming sockets with Python scripts. This section shows you how to use the Python socket interface to perform low-level network communications. In later chapters, we will instead use one of the higher-level protocol modules that hide underlying sockets. Python’s socket interfaces can be used directly, though, to implement custom network dialogs and to access standard protocols manually.
As previewed in Chapter 5, the
basic socket interface in Python is the standard library’s
socket module. Like the
os POSIX module, Python’s
socket module is just a thin wrapper
(interface layer) over the underlying C library’s socket calls. Like
Python files, it’s also object-based—methods of a socket object
implemented by this module call out to the corresponding C library’s
operations after data conversions. For instance, the C library’s
recv function calls become methods of socket
objects in Python.
supports socket programming on any machine that supports BSD-style
sockets—Windows, Macs, Linux, Unix, and so on—and so provides a
portable socket interface. In addition, this module supports all
commonly used socket types—TCP/IP, UDP, datagram, and Unix
domain—and can be used as both a network interface API and a general
IPC mechanism between processes running on the same machine.
From a functional perspective, sockets are ...