Class | BasicSocket |
In: |
ext/socket/socket.c
|
Parent: | IO |
Class Socket provides access to the underlying operating system socket implementations. It can be used to provide more operating system specific functionality than the protocol-specific socket classes but at the expense of greater complexity. In particular, the class handles addresses using +struct sockaddr+ structures packed into Ruby strings, which can be a joy to manipulate.
Ruby‘s implementation of Socket causes an exception to be raised based on the error generated by the system dependent implementation. This is why the methods are documented in a way that isolate Unix-based system exceptions from Windows based exceptions. If more information on particular exception is needed please refer to the Unix manual pages or the Windows WinSock reference.
Much material in this documentation is taken with permission from Programming Ruby from The Pragmatic Bookshelf.
Gets a socket option. These are protocol and system specific, see your local sytem documentation for details. The option is returned as a String with the data being the binary value of the socket option.
Some socket options are integers with boolean values, in this case getsockopt could be called like this:
optval = sock.getsockopt(Socket::SOL_SOCKET,Socket::SO_REUSEADDR) optval = optval.unpack "i" reuseaddr = optval[0] == 0 ? false : true
Some socket options are integers with numeric values, in this case getsockopt could be called like this:
optval = sock.getsockopt(Socket::IPPROTO_IP, Socket::IP_TTL) ipttl = optval.unpack("i")[0]
Option values may be structs. Decoding them can be complex as it involves examining your system headers to determine the correct definition. An example is a +struct linger+, which may be defined in your system headers as:
struct linger { int l_onoff; int l_linger; };
In this case getsockopt could be called like this:
optval = sock.getsockopt(Socket::SOL_SOCKET, Socket::SO_LINGER) onoff, linger = optval.unpack "ii"
/* * Document-method: getsockopt * call-seq: getsockopt(level, optname) * * Gets a socket option. These are protocol and system specific, see your * local sytem documentation for details. The option is returned as * a String with the data being the binary value of the socket option. * * === Parameters * * +level+ is an integer, usually one of the SOL_ constants such as * Socket::SOL_SOCKET, or a protocol level. * * +optname+ is an integer, usually one of the SO_ constants, such * as Socket::SO_REUSEADDR. * * === Examples * * Some socket options are integers with boolean values, in this case * #getsockopt could be called like this: * optval = sock.getsockopt(Socket::SOL_SOCKET,Socket::SO_REUSEADDR) * optval = optval.unpack "i" * reuseaddr = optval[0] == 0 ? false : true * * Some socket options are integers with numeric values, in this case * #getsockopt could be called like this: * optval = sock.getsockopt(Socket::IPPROTO_IP, Socket::IP_TTL) * ipttl = optval.unpack("i")[0] * * Option values may be structs. Decoding them can be complex as it involves * examining your system headers to determine the correct definition. An * example is a +struct linger+, which may be defined in your system headers * as: * struct linger { * int l_onoff; * int l_linger; * }; * * In this case #getsockopt could be called like this: * optval = sock.getsockopt(Socket::SOL_SOCKET, Socket::SO_LINGER) * onoff, linger = optval.unpack "ii" */ static VALUE bsock_getsockopt(sock, lev, optname) VALUE sock, lev, optname; { #if !defined(__BEOS__) int level, option; socklen_t len; char *buf; rb_io_t *fptr; level = NUM2INT(lev); option = NUM2INT(optname); len = 256; buf = ALLOCA_N(char,len); GetOpenFile(sock, fptr); GetOpenFile(sock, fptr); if (getsockopt(fileno(fptr->f), level, option, buf, &len) < 0) rb_sys_fail(fptr->path); return rb_str_new(buf, len); #else rb_notimplement(); #endif }
Receives up to maxlen bytes from socket using recvfrom(2) after O_NONBLOCK is set for the underlying file descriptor. flags is zero or more of the MSG_ options. The result, mesg, is the data received.
When recvfrom(2) returns 0, Socket#recv_nonblock returns an empty string as data. The meaning depends on the socket: EOF on TCP, empty packet on UDP, etc.
serv = TCPServer.new("127.0.0.1", 0) af, port, host, addr = serv.addr c = TCPSocket.new(addr, port) s = serv.accept c.send "aaa", 0 IO.select([s]) p s.recv_nonblock(10) #=> "aaa"
Refer to Socket#recvfrom for the exceptions that may be thrown if the call to recv_nonblock fails.
BasicSocket#recv_nonblock may raise any error corresponding to recvfrom(2) failure, including Errno::EAGAIN.
/* * call-seq: * basicsocket.recv_nonblock(maxlen) => mesg * basicsocket.recv_nonblock(maxlen, flags) => mesg * * Receives up to _maxlen_ bytes from +socket+ using recvfrom(2) after * O_NONBLOCK is set for the underlying file descriptor. * _flags_ is zero or more of the +MSG_+ options. * The result, _mesg_, is the data received. * * When recvfrom(2) returns 0, Socket#recv_nonblock returns * an empty string as data. * The meaning depends on the socket: EOF on TCP, empty packet on UDP, etc. * * === Parameters * * +maxlen+ - the number of bytes to receive from the socket * * +flags+ - zero or more of the +MSG_+ options * * === Example * serv = TCPServer.new("127.0.0.1", 0) * af, port, host, addr = serv.addr * c = TCPSocket.new(addr, port) * s = serv.accept * c.send "aaa", 0 * IO.select([s]) * p s.recv_nonblock(10) #=> "aaa" * * Refer to Socket#recvfrom for the exceptions that may be thrown if the call * to _recv_nonblock_ fails. * * BasicSocket#recv_nonblock may raise any error corresponding to recvfrom(2) failure, * including Errno::EAGAIN. * * === See * * Socket#recvfrom */ static VALUE bsock_recv_nonblock(argc, argv, sock) int argc; VALUE *argv; VALUE sock; { return s_recvfrom_nonblock(sock, argc, argv, RECV_RECV); }
Sets a socket option. These are protocol and system specific, see your local sytem documentation for details.
Some socket options are integers with boolean values, in this case setsockopt could be called like this:
sock.setsockopt(Socket::SOL_SOCKET,Socket::SO_REUSEADDR, true)
Some socket options are integers with numeric values, in this case setsockopt could be called like this:
sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_TTL, 255)
Option values may be structs. Passing them can be complex as it involves examining your system headers to determine the correct definition. An example is an ip_mreq, which may be defined in your system headers as:
struct ip_mreq { struct in_addr imr_multiaddr; struct in_addr imr_interface; };
In this case setsockopt could be called like this:
optval = IPAddr.new("224.0.0.251") + Socket::INADDR_ANY sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, optval)
/* * Document-method: setsockopt * call-seq: setsockopt(level, optname, optval) * * Sets a socket option. These are protocol and system specific, see your * local sytem documentation for details. * * === Parameters * * +level+ is an integer, usually one of the SOL_ constants such as * Socket::SOL_SOCKET, or a protocol level. * * +optname+ is an integer, usually one of the SO_ constants, such * as Socket::SO_REUSEADDR. * * +optval+ is the value of the option, it is passed to the underlying * setsockopt() as a pointer to a certain number of bytes. How this is * done depends on the type: * - Fixnum: value is assigned to an int, and a pointer to the int is * passed, with length of sizeof(int). * - true or false: 1 or 0 (respectively) is assigned to an int, and the * int is passed as for a Fixnum. Note that +false+ must be passed, * not +nil+. * - String: the string's data and length is passed to the socket. * * === Examples * * Some socket options are integers with boolean values, in this case * #setsockopt could be called like this: * sock.setsockopt(Socket::SOL_SOCKET,Socket::SO_REUSEADDR, true) * * Some socket options are integers with numeric values, in this case * #setsockopt could be called like this: * sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_TTL, 255) * * Option values may be structs. Passing them can be complex as it involves * examining your system headers to determine the correct definition. An * example is an +ip_mreq+, which may be defined in your system headers as: * struct ip_mreq { * struct in_addr imr_multiaddr; * struct in_addr imr_interface; * }; * * In this case #setsockopt could be called like this: * optval = IPAddr.new("224.0.0.251") + Socket::INADDR_ANY * sock.setsockopt(Socket::IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, optval) * */ static VALUE bsock_setsockopt(sock, lev, optname, val) VALUE sock, lev, optname, val; { int level, option; rb_io_t *fptr; int i; char *v; int vlen; rb_secure(2); level = NUM2INT(lev); option = NUM2INT(optname); switch (TYPE(val)) { case T_FIXNUM: i = FIX2INT(val); goto numval; case T_FALSE: i = 0; goto numval; case T_TRUE: i = 1; numval: v = (char*)&i; vlen = sizeof(i); break; default: StringValue(val); v = RSTRING(val)->ptr; vlen = RSTRING(val)->len; break; } GetOpenFile(sock, fptr); if (setsockopt(fileno(fptr->f), level, option, v, vlen) < 0) rb_sys_fail(fptr->path); return INT2FIX(0); }