1IO::Async::Socket(3) User Contributed Perl Documentation IO::Async::Socket(3)
2
6 "IO::Async::Socket" - event callbacks and send buffering for a socket
7 filehandle
8
10 use IO::Async::Socket;
11 use IO::Async::Loop;
13 my $loop = IO::Async::Loop->new;
14 my $socket = IO::Async::Socket->new(
16 on_recv => sub {
17 my ( $self, $dgram, $addr ) = @_;
18 print "Received reply: $dgram\n",
20 $loop->stop;
21 },
22 on_recv_error => sub {
23 my ( $self, $errno ) = @_;
24 die "Cannot recv - $errno\n";
25 },
26 );
27 $loop->add( $socket );
28 $socket->connect(
30 host => "some.host.here",
31 service => "echo",
32 socktype => 'dgram',
33 )->get;
34 $socket->send( "A TEST DATAGRAM" );
36 $loop->run;
38
40 This subclass of IO::Async::Handle contains a socket filehandle. It
41 provides a queue of outgoing data. It invokes the "on_recv" handler
42 when new data is received from the filehandle. Data may be sent to the
43 filehandle by calling the "send" method.
44 It is primarily intended for "SOCK_DGRAM" or "SOCK_RAW" sockets (such
46 as UDP or packet-capture); for "SOCK_STREAM" sockets (such as TCP) an
47 instance of IO::Async::Stream is more appropriate.
48
50 The following events are invoked, either using subclass methods or CODE
51 references in parameters:
52 on_recv $data, $addr
54 Invoke on receipt of a packet, datagram, or stream segment.
55 The "on_recv" handler is invoked once for each packet, datagram, or
57 stream segment that is received. It is passed the data itself, and the
58 sender's address.
59 on_recv_error $errno
61 Optional. Invoked when the "recv" method on the receiving handle fails.
62 on_send_error $errno
64 Optional. Invoked when the "send" method on the sending handle fails.
65 The "on_recv_error" and "on_send_error" handlers are passed the value
67 of $! at the time the error occurred. (The $! variable itself, by its
68 nature, may have changed from the original error by the time this
69 handler runs so it should always use the value passed in).
70 If an error occurs when the corresponding error callback is not
72 supplied, and there is not a subclass method for it, then the "close"
73 method is called instead.
74 on_outgoing_empty
76 Optional. Invoked when the sending data buffer becomes empty.
77
79 The following named parameters may be passed to "new" or "configure":
80 read_handle => IO
82 The IO handle to receive from. Must implement "fileno" and "recv"
83 methods.
84 write_handle => IO
86 The IO handle to send to. Must implement "fileno" and "send" methods.
87 handle => IO
89 Shortcut to specifying the same IO handle for both of the above.
90 on_recv => CODE
92 on_recv_error => CODE
93 on_outgoing_empty => CODE
94 on_send_error => CODE
95 autoflush => BOOL
96 Optional. If true, the "send" method will atempt to send data to the
97 operating system immediately, without waiting for the loop to indicate
98 the filehandle is write-ready.
99 recv_len => INT
101 Optional. Sets the buffer size for "recv" calls. Defaults to 64 KiB.
102 recv_all => BOOL
104 Optional. If true, repeatedly call "recv" when the receiving handle
105 first becomes read-ready. By default this is turned off, meaning at
106 most one fixed-size buffer is received. If there is still more data in
107 the kernel's buffer, the handle will stil be readable, and will be
108 received from again.
109 This behaviour allows multiple streams and sockets to be multiplexed
111 simultaneously, meaning that a large bulk transfer on one cannot starve
112 other filehandles of processing time. Turning this option on may
113 improve bulk data transfer rate, at the risk of delaying or stalling
114 processing on other filehandles.
115 send_all => INT
117 Optional. Analogous to the "recv_all" option, but for sending. When
118 "autoflush" is enabled, this option only affects deferred sending if
119 the initial attempt failed.
120 The condition requiring an "on_recv" handler is checked at the time the
122 object is added to a Loop; it is allowed to create a
123 "IO::Async::Socket" object with a read handle but without a "on_recv"
124 handler, provided that one is later given using "configure" before the
125 stream is added to its containing Loop, either directly or by being a
126 child of another Notifier already in a Loop, or added to one.
127
129 send
130 $socket->send( $data, $flags, $addr )
131 This method adds a segment of data to be sent, or sends it immediately,
133 according to the "autoflush" parameter. $flags and $addr are optional.
134 If the "autoflush" option is set, this method will try immediately to
136 send the data to the underlying filehandle, optionally using the given
137 flags and destination address. If this completes successfully then it
138 will have been sent by the time this method returns. If it fails to
139 send, then the data is queued as if "autoflush" were not set, and will
140 be flushed as normal.
141
143 Send-first on a UDP Socket
144 "UDP" is carried by the "SOCK_DGRAM" socket type, for which the string
145 'dgram' is a convenient shortcut:
146 $socket->connect(
148 host => $hostname,
149 service => $service,
150 socktype => 'dgram',
151 ...
152 )
153 Receive-first on a UDP Socket
155 A typical server pattern with "UDP" involves binding a well-known port
156 number instead of connecting to one, and waiting on incoming packets.
157 $socket->bind(
159 service => 12345,
160 socktype => 'dgram',
161 )->get;
162
164 ยท IO::Handle - Supply object methods for I/O handles
165
167 Paul Evans <leonerd@leonerd.org.uk>
168perl v5.30.0 2019-07-26 IO::Async::Socket(3)