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<TITLE>Socket Objects -- Python library reference</TITLE> Next: <A HREF="../s/socket_example" TYPE="Next">Socket Example</A> Prev: <A HREF="../s/socket" TYPE="Prev">socket</A> Up: <A HREF="../s/socket" TYPE="Up">socket</A> Top: <A HREF="../t/top" TYPE="Top">Top</A> <H2>7.2.1. Socket Objects</H2> Socket objects have the following methods. Except for <CODE>makefile()</CODE> these correspond to UNIX system calls applicable to sockets. <DL><DT>accept () -- Method on socket<DD> Accept a connection. The socket must be bound to an address and listening for connections. The return value is a pair <CODE>(<VAR>conn</VAR>, <VAR>address</VAR>)</CODE> where <VAR>conn</VAR> is a new socket object usable to send and receive data on the connection, and <VAR>address</VAR> is the address bound to the socket on the other end of the connection. </DL> <DL><DT>bind (<VAR>address</VAR>) -- Method on socket<DD> Bind the socket to <VAR>address</VAR>. The socket must not already be bound. (The format of <VAR>address</VAR> depends on the address family --- see above.) </DL> <DL><DT>close () -- Method on socket<DD> Close the socket. All future operations on the socket object will fail. The remote end will receive no more data (after queued data is flushed). Sockets are automatically closed when they are garbage-collected. </DL> <DL><DT>connect (<VAR>address</VAR>) -- Method on socket<DD> Connect to a remote socket at <VAR>address</VAR>. (The format of <VAR>address</VAR> depends on the address family --- see above.) </DL> <DL><DT>fileno () -- Method on socket<DD> Return the socket's file descriptor (a small integer). This is useful with <CODE>select</CODE>. </DL> <DL><DT>getpeername () -- Method on socket<DD> Return the remote address to which the socket is connected. This is useful to find out the port number of a remote IP socket, for instance. (The format of the address returned depends on the address family --- see above.) On some systems this function is not supported. </DL> <DL><DT>getsockname () -- Method on socket<DD> Return the socket's own address. This is useful to find out the port number of an IP socket, for instance. (The format of the address returned depends on the address family --- see above.) </DL> <DL><DT>getsockopt (<VAR>level</VAR>, <VAR>optname</VAR>[, <VAR>buflen</VAR>]) -- Method on socket<DD> Return the value of the given socket option (see the UNIX man page getsockopt(2)). The needed symbolic constants (<CODE>SO_*</CODE> etc.) are defined in this module. If <VAR>buflen</VAR> is absent, an integer option is assumed and its integer value is returned by the function. If <VAR>buflen</VAR> is present, it specifies the maximum length of the buffer used to receive the option in, and this buffer is returned as a string. It is up to the caller to decode the contents of the buffer (see the optional built-in module <CODE>struct</CODE> for a way to decode C structures encoded as strings). </DL> <DL><DT>listen (<VAR>backlog</VAR>) -- Method on socket<DD> Listen for connections made to the socket. The <VAR>backlog</VAR> argument specifies the maximum number of queued connections and should be at least 1; the maximum value is system-dependent (usually 5). </DL> <DL><DT>makefile ([<VAR>mode</VAR>[, <VAR>bufsize</VAR>]]) -- Method on socket<DD> Return a <DFN>file object</DFN> associated with the socket. (File objects were described earlier under Built-in Types.) The file object references a <CODE>dup()</CODE>ped version of the socket file descriptor, so the file object and socket object may be closed or garbage-collected independently. The optional <VAR>mode</VAR> and <VAR>bufsize</VAR> arguments are interpreted the same way as by the built-in <CODE>open()</CODE> function. </DL> <DL><DT>recv (<VAR>bufsize</VAR>[, <VAR>flags</VAR>]) -- Method on socket<DD> Receive data from the socket. The return value is a string representing the data received. The maximum amount of data to be received at once is specified by <VAR>bufsize</VAR>. See the UNIX manual page for the meaning of the optional argument <VAR>flags</VAR>; it defaults to zero. </DL> <DL><DT>recvfrom (<VAR>bufsize</VAR>[, <VAR>flags</VAR>]) -- Method on socket<DD> Receive data from the socket. The return value is a pair <CODE>(<VAR>string</VAR>, <VAR>address</VAR>)</CODE> where <VAR>string</VAR> is a string representing the data received and <VAR>address</VAR> is the address of the socket sending the data. The optional <VAR>flags</VAR> argument has the same meaning as for <CODE>recv()</CODE> above. (The format of <VAR>address</VAR> depends on the address family --- see above.) </DL> <DL><DT>send (<VAR>string</VAR>[, <VAR>flags</VAR>]) -- Method on socket<DD> Send data to the socket. The socket must be connected to a remote socket. The optional <VAR>flags</VAR> argument has the same meaning as for <CODE>recv()</CODE> above. Return the number of bytes sent. </DL> <DL><DT>sendto (<VAR>string</VAR>[, <VAR>flags</VAR>], <VAR>address</VAR>) -- Method on socket<DD> Send data to the socket. The socket should not be connected to a remote socket, since the destination socket is specified by <CODE>address</CODE>. The optional <VAR>flags</VAR> argument has the same meaning as for <CODE>recv()</CODE> above. Return the number of bytes sent. (The format of <VAR>address</VAR> depends on the address family --- see above.) </DL> <DL><DT>setblocking (<VAR>flag</VAR>) -- Method on socket<DD> Set blocking or non-blocking mode of the socket: if <VAR>flag</VAR> is 0, the socket is set to non-blocking, else to blocking mode. Initially all sockets are in blocking mode. In non-blocking mode, if a <CODE>recv</CODE> call doesn't find any data, or if a <CODE>send</CODE> call can't immediately dispose of the data, a <CODE>socket.error</CODE> exception is raised; in blocking mode, the calls block until they can proceed. </DL> <DL><DT>setsockopt (<VAR>level</VAR>, <VAR>optname</VAR>, <VAR>value</VAR>) -- Method on socket<DD> Set the value of the given socket option (see the UNIX man page setsockopt(2)). The needed symbolic constants are defined in the <CODE>socket</CODE> module (<CODE>SO_*</CODE> etc.). The value can be an integer or a string representing a buffer. In the latter case it is up to the caller to ensure that the string contains the proper bits (see the optional built-in module <CODE>struct</CODE> for a way to encode C structures as strings). </DL> <DL><DT>shutdown (<VAR>how</VAR>) -- Method on socket<DD> Shut down one or both halves of the connection. If <VAR>how</VAR> is <CODE>0</CODE>, further receives are disallowed. If <VAR>how</VAR> is <CODE>1</CODE>, further sends are disallowed. If <VAR>how</VAR> is <CODE>2</CODE>, further sends and receives are disallowed. </DL> Note that there are no methods <CODE>read()</CODE> or <CODE>write()</CODE>; use <CODE>recv()</CODE> and <CODE>send()</CODE> without <VAR>flags</VAR> argument instead.