socket This module provides access to the BSD socket interface. It is available on systems that support this interface.
For an introduction to socket programming (in C), see the following papers: An Introductory 4.3BSD Interprocess Communication Tutorial, by Stuart Sechrest and An Advanced 4.3BSD Interprocess Communication Tutorial, by Samuel J. Leffler et al, both in the Programmer's Manual, Supplementary Documents 1 (sections PS1:7 and PS1:8). The manual pages for the various socket-related system calls also a valuable source of information on the details of socket semantics.
The Python interface is a straightforward transliteration of the system call and library interface for sockets to Python's object-oriented style: the socket() function returns a socket object whose methods implement the various socket system calls. Parameter types are somewhat higer-level than in the C interface: as with read() and write() operations on Python files, buffer allocation on receive operations is automatic, and buffer length is implicit on send operations.
Socket addresses are represented as a single string for the AF_UNIX address family and as a pair (host, port) for the AF_INET address family, where host is a string representing either a hostname in Internet domain notation like 'daring.cwi.nl' or an IP address like '100.50.200.5', and port is an integral port number. Other address families are currently not supported. The address format required by a particular socket object is automatically selected based on the address family specified when the socket object was created.
All errors raise exceptions. The normal exceptions for invalid argument types and out-of-memory conditions can be raised; errors related to socket or address semantics raise the error socket.error.
Non-blocking and asynchronous mode are not supported; see module select for a way to do non-blocking socket I/O.
The module socket exports the following constants and functions:
