Creates a new Hash using the key-value pairs from the database, then calls Hash#reject with the given block, which returns a Hash with only the key-value pairs for which the block returns false.
Empties the database, then inserts the given key-value pairs.
This method will work with any object which implements an each_pair method, such as a Hash.
Returns a new Array containing each key-value pair in the database.
Example:
require 'sdbm' SDBM.open 'my_database' do |db| db.update('apple' => 'fruit', 'spinach' => 'vegetable') db.to_a #=> [["apple", "fruit"], ["spinach", "vegetable"]] end
Listens for connections, using the specified int as the backlog. A call to listen only applies if the socket is of type SOCK_STREAM or SOCK_SEQPACKET.
backlog - the maximum length of the queue for pending connections.
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 )
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) socket.listen( 1 )
On unix based systems the above will work because a new sockaddr struct is created on the address ADDR_ANY, for an arbitrary port number as handed off by the kernel. It will not work on Windows, because Windows requires that the socket is bound by calling bind before it can listen.
If the backlog amount exceeds the implementation-dependent maximum queue length, the implementation’s maximum queue length will be used.
On unix-based based systems the following system exceptions may be raised if the call to listen fails:
Errno::EBADF - the socket argument is not a valid file descriptor
Errno::EDESTADDRREQ - the socket is not bound to a local address, and the protocol does not support listening on an unbound socket
Errno::EINVAL - the socket is already connected
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::EOPNOTSUPP - the socket protocol does not support listen
Errno::EACCES - the calling process does not have appropriate privileges
Errno::EINVAL - the socket has been shut down
Errno::ENOBUFS - insufficient resources are available in the system to complete the call
On Windows systems the following system exceptions may be raised if the call to listen fails:
Errno::ENETDOWN - the network is down
Errno::EADDRINUSE - the socket’s local address is already in use. This usually occurs during the execution of bind but could be delayed if the call to bind was to a partially wildcard address (involving ADDR_ANY) and if a specific address needs to be committed at the time of the call to listen
Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - the socket has not been bound with a call to bind.
Errno::EISCONN - the socket is already connected
Errno::EMFILE - no more socket descriptors are available
Errno::ENOBUFS - no buffer space is available
Errno::ENOTSOC - socket is not a socket
Errno::EOPNOTSUPP - the referenced socket is not a type that supports the listen method
listen manual pages on unix-based systems
listen function in Microsoft’s Winsock functions reference
Receives up to maxlen bytes from socket. flags is zero or more of the MSG_ options. The first element of the results, mesg, is the data received. The second element, sender_addrinfo, contains protocol-specific address information of the sender.
maxlen - the maximum number of bytes to receive from the socket
flags - zero or more of the MSG_ options
# In one file, start this first require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 ) client, client_addrinfo = socket.accept data = client.recvfrom( 20 )[0].chomp puts "I only received 20 bytes '#{data}'" sleep 1 socket.close # In another file, start this second require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.connect( sockaddr ) socket.puts "Watch this get cut short!" socket.close
On unix-based based systems the following system exceptions may be raised if the call to recvfrom fails:
Errno::EAGAIN - the socket file descriptor is marked as O_NONBLOCK and no data is waiting to be received; or MSG_OOB is set and no out-of-band data is available and either the socket file descriptor is marked as O_NONBLOCK or the socket does not support blocking to wait for out-of-band-data
Errno::EWOULDBLOCK - see Errno::EAGAIN
Errno::EBADF - the socket is not a valid file descriptor
Errno::ECONNRESET - a connection was forcibly closed by a peer
Errno::EFAULT - the socket’s internal buffer, address or address length cannot be accessed or written
Errno::EINTR - a signal interrupted recvfrom before any data was available
Errno::EINVAL - the MSG_OOB flag is set and no out-of-band data is available
Errno::EIO - an i/o error occurred while reading from or writing to the filesystem
Errno::ENOBUFS - insufficient resources were available in the system to perform the operation
Errno::ENOMEM - insufficient memory was available to fulfill the request
Errno::ENOSR - there were insufficient STREAMS resources available to complete the operation
Errno::ENOTCONN - a receive is attempted on a connection-mode socket that is not connected
Errno::ENOTSOCK - the socket does not refer to a socket
Errno::EOPNOTSUPP - the specified flags are not supported for this socket type
Errno::ETIMEDOUT - the connection timed out during connection establishment or due to a transmission timeout on an active connection
On Windows systems the following system exceptions may be raised if the call to recvfrom fails:
Errno::ENETDOWN - the network is down
Errno::EFAULT - the internal buffer and from parameters on socket are not part of the user address space, or the internal fromlen parameter is too small to accommodate the peer address
Errno::EINTR - the (blocking) call was cancelled by an internal call to the WinSock function WSACancelBlockingCall
Errno::EINPROGRESS - a blocking Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - socket has not been bound with a call to bind, or an unknown flag was specified, or MSG_OOB was specified for a socket with SO_OOBINLINE enabled, or (for byte stream-style sockets only) the internal len parameter on socket was zero or negative
Errno::EISCONN - socket is already connected. The call to recvfrom is not permitted with a connected socket on a socket that is connection oriented or connectionless.
Errno::ENETRESET - the connection has been broken due to the keep-alive activity detecting a failure while the operation was in progress.
Errno::EOPNOTSUPP - MSG_OOB was specified, but socket is not stream-style such as type SOCK_STREAM. OOB data is not supported in the communication domain associated with socket, or socket is unidirectional and supports only send operations
Errno::ESHUTDOWN - socket has been shutdown. It is not possible to call recvfrom on a socket after shutdown has been invoked.
Errno::EWOULDBLOCK - socket is marked as nonblocking and a call to recvfrom would block.
Errno::EMSGSIZE - the message was too large to fit into the specified buffer and was truncated.
Errno::ETIMEDOUT - the connection has been dropped, because of a network failure or because the system on the other end went down without notice
Errno::ECONNRESET - the virtual circuit was reset by the remote side executing a hard or abortive close. The application should close the socket; it is no longer usable. On a UDP-datagram socket this error indicates a previous send operation resulted in an ICMP Port Unreachable message.
Returns the hostname.
p Socket.gethostname #=> "hal"
Note that it is not guaranteed to be able to convert to IP address using gethostbyname, getaddrinfo, etc. If you need local IP address, use Socket.ip_address_list.
Use Addrinfo.getaddrinfo instead. This method is deprecated for the following reasons:
The 3rd element of the result is the address family of the first address. The address families of the rest of the addresses are not returned.
Uncommon address representation: 4/16-bytes binary string to represent IPv4/IPv6 address.
gethostbyname() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.
This method obtains the host information for hostname.
p Socket.gethostbyname("hal") #=> ["localhost", ["hal"], 2, "\x7F\x00\x00\x01"]
Use Addrinfo#getnameinfo instead. This method is deprecated for the following reasons:
Uncommon address representation: 4/16-bytes binary string to represent IPv4/IPv6 address.
gethostbyaddr() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.
This method obtains the host information for address.
p Socket.gethostbyaddr([221,186,184,68].pack("CCCC"))
#=> ["carbon.ruby-lang.org", [], 2, "\xDD\xBA\xB8D"]
p Socket.gethostbyaddr([127,0,0,1].pack("CCCC"))
["localhost", [], 2, "\x7F\x00\x00\x01"]
p Socket.gethostbyaddr(([0]*15+[1]).pack("C"*16))
#=> ["localhost", ["ip6-localhost", "ip6-loopback"], 10,
"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"]
Obtains the port number for port.
If protocol_name is not given, “tcp” is assumed.
Socket.getservbyport(80) #=> "www" Socket.getservbyport(514, "tcp") #=> "shell" Socket.getservbyport(514, "udp") #=> "syslog"
Returns the user and group on the peer of the UNIX socket. The result is a two element array which contains the effective uid and the effective gid.
Socket.unix_server_loop("/tmp/sock") {|s| begin euid, egid = s.getpeereid # Check the connected client is myself or not. next if euid != Process.uid # do something about my resource. ensure s.close end }
Receives a message.
maxlen is the maximum number of bytes to receive.
flags should be a bitwise OR of Socket::MSG_* constants.
outbuf will contain only the received data after the method call even if it is not empty at the beginning.
UNIXSocket.pair {|s1, s2| s1.puts "Hello World" p s2.recv(4) #=> "Hell" p s2.recv(4, Socket::MSG_PEEK) #=> "o Wo" p s2.recv(4) #=> "o Wo" p s2.recv(10) #=> "rld\n" }
recvmsg receives a message using recvmsg(2) system call in blocking manner.
maxmesglen is the maximum length of mesg to receive.
flags is bitwise OR of MSG_* constants such as Socket::MSG_PEEK.
maxcontrollen is the maximum length of controls (ancillary data) to receive.
opts is option hash. Currently :scm_rights=>bool is the only option.
:scm_rights option specifies that application expects SCM_RIGHTS control message. If the value is nil or false, application don’t expects SCM_RIGHTS control message. In this case, recvmsg closes the passed file descriptors immediately. This is the default behavior.
If :scm_rights value is neither nil nor false, application expects SCM_RIGHTS control message. In this case, recvmsg creates IO objects for each file descriptors for Socket::AncillaryData#unix_rights method.
The return value is 4-elements array.
mesg is a string of the received message.
sender_addrinfo is a sender socket address for connection-less socket. It is an Addrinfo object. For connection-oriented socket such as TCP, sender_addrinfo is platform dependent.
rflags is a flags on the received message which is bitwise OR of MSG_* constants such as Socket::MSG_TRUNC. It will be nil if the system uses 4.3BSD style old recvmsg system call.
controls is ancillary data which is an array of Socket::AncillaryData objects such as:
#<Socket::AncillaryData: AF_UNIX SOCKET RIGHTS 7>
maxmesglen and maxcontrollen can be nil. In that case, the buffer will be grown until the message is not truncated. Internally, MSG_PEEK is used. Buffer full and MSG_CTRUNC are checked for truncation.
recvmsg can be used to implement recv_io as follows:
mesg, sender_sockaddr, rflags, *controls = sock.recvmsg(:scm_rights=>true) controls.each {|ancdata| if ancdata.cmsg_is?(:SOCKET, :RIGHTS) return ancdata.unix_rights[0] end }
Receives a message and return the message as a string and an address which the message come from.
maxlen is the maximum number of bytes to receive.
flags should be a bitwise OR of Socket::MSG_* constants.
ipaddr is same as IPSocket#{peeraddr,addr}.
u1 = UDPSocket.new u1.bind("127.0.0.1", 4913) u2 = UDPSocket.new u2.send "uuuu", 0, "127.0.0.1", 4913 p u1.recvfrom(10) #=> ["uuuu", ["AF_INET", 33230, "localhost", "127.0.0.1"]]
Lookups the IP address of host.
require 'socket' IPSocket.getaddress("localhost") #=> "127.0.0.1" IPSocket.getaddress("ip6-localhost") #=> "::1"
creates a listening socket bound to self.
returns the socket type as an integer.
Addrinfo.tcp("localhost", 80).protocol == Socket::IPPROTO_TCP #=> true
returns the socket address as packed struct sockaddr string.
Addrinfo.tcp("localhost", 80).to_sockaddr #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00"
Listens for connections, using the specified int as the backlog. A call to listen only applies if the socket is of type SOCK_STREAM or SOCK_SEQPACKET.
backlog - the maximum length of the queue for pending connections.
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 )
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) socket.listen( 1 )
On unix based systems the above will work because a new sockaddr struct is created on the address ADDR_ANY, for an arbitrary port number as handed off by the kernel. It will not work on Windows, because Windows requires that the socket is bound by calling bind before it can listen.
If the backlog amount exceeds the implementation-dependent maximum queue length, the implementation’s maximum queue length will be used.
On unix-based based systems the following system exceptions may be raised if the call to listen fails:
Errno::EBADF - the socket argument is not a valid file descriptor
Errno::EDESTADDRREQ - the socket is not bound to a local address, and the protocol does not support listening on an unbound socket
Errno::EINVAL - the socket is already connected
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::EOPNOTSUPP - the socket protocol does not support listen
Errno::EACCES - the calling process does not have appropriate privileges
Errno::EINVAL - the socket has been shut down
Errno::ENOBUFS - insufficient resources are available in the system to complete the call
On Windows systems the following system exceptions may be raised if the call to listen fails:
Errno::ENETDOWN - the network is down
Errno::EADDRINUSE - the socket’s local address is already in use. This usually occurs during the execution of bind but could be delayed if the call to bind was to a partially wildcard address (involving ADDR_ANY) and if a specific address needs to be committed at the time of the call to listen
Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - the socket has not been bound with a call to bind.
Errno::EISCONN - the socket is already connected
Errno::EMFILE - no more socket descriptors are available
Errno::ENOBUFS - no buffer space is available
Errno::ENOTSOC - socket is not a socket
Errno::EOPNOTSUPP - the referenced socket is not a type that supports the listen method
listen manual pages on unix-based systems
listen function in Microsoft’s Winsock functions reference
Listens for connections, using the specified int as the backlog. A call to listen only applies if the socket is of type SOCK_STREAM or SOCK_SEQPACKET.
backlog - the maximum length of the queue for pending connections.
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' ) socket.bind( sockaddr ) socket.listen( 5 )
require 'socket' include Socket::Constants socket = Socket.new( AF_INET, SOCK_STREAM, 0 ) socket.listen( 1 )
On unix based systems the above will work because a new sockaddr struct is created on the address ADDR_ANY, for an arbitrary port number as handed off by the kernel. It will not work on Windows, because Windows requires that the socket is bound by calling bind before it can listen.
If the backlog amount exceeds the implementation-dependent maximum queue length, the implementation’s maximum queue length will be used.
On unix-based based systems the following system exceptions may be raised if the call to listen fails:
Errno::EBADF - the socket argument is not a valid file descriptor
Errno::EDESTADDRREQ - the socket is not bound to a local address, and the protocol does not support listening on an unbound socket
Errno::EINVAL - the socket is already connected
Errno::ENOTSOCK - the socket argument does not refer to a socket
Errno::EOPNOTSUPP - the socket protocol does not support listen
Errno::EACCES - the calling process does not have appropriate privileges
Errno::EINVAL - the socket has been shut down
Errno::ENOBUFS - insufficient resources are available in the system to complete the call
On Windows systems the following system exceptions may be raised if the call to listen fails:
Errno::ENETDOWN - the network is down
Errno::EADDRINUSE - the socket’s local address is already in use. This usually occurs during the execution of bind but could be delayed if the call to bind was to a partially wildcard address (involving ADDR_ANY) and if a specific address needs to be committed at the time of the call to listen
Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the service provider is still processing a callback function
Errno::EINVAL - the socket has not been bound with a call to bind.
Errno::EISCONN - the socket is already connected
Errno::EMFILE - no more socket descriptors are available
Errno::ENOBUFS - no buffer space is available
Errno::ENOTSOC - socket is not a socket
Errno::EOPNOTSUPP - the referenced socket is not a type that supports the listen method
listen manual pages on unix-based systems
listen function in Microsoft’s Winsock functions reference
Use Addrinfo.getaddrinfo instead. This method is deprecated for the following reasons:
The 3rd element of the result is the address family of the first address. The address families of the rest of the addresses are not returned.
gethostbyname() may take a long time and it may block other threads. (GVL cannot be released since gethostbyname() is not thread safe.)
This method uses gethostbyname() function already removed from POSIX.
This method lookups host information by hostname.
TCPSocket.gethostbyname("localhost") #=> ["localhost", ["hal"], 2, "127.0.0.1"]
Receives a message via unixsocket.
maxlen is the maximum number of bytes to receive.
flags should be a bitwise OR of Socket::MSG_* constants.
outbuf will contain only the received data after the method call even if it is not empty at the beginning.
s1 = Socket.new(:UNIX, :DGRAM, 0) s1_ai = Addrinfo.unix("/tmp/sock1") s1.bind(s1_ai) s2 = Socket.new(:UNIX, :DGRAM, 0) s2_ai = Addrinfo.unix("/tmp/sock2") s2.bind(s2_ai) s3 = UNIXSocket.for_fd(s2.fileno) s1.send "a", 0, s2_ai p s3.recvfrom(10) #=> ["a", ["AF_UNIX", "/tmp/sock1"]]
Reinitializes the stream with the given other_StrIO or string and mode (see StringIO#new).
Positions the stream to the beginning of input, resetting lineno to zero.