Current File : //proc/self/root/usr/src/node-v0.10.4/doc/api/dgram.json
{
"source": "doc/api/dgram.markdown",
"modules": [
{
"textRaw": "UDP / Datagram Sockets",
"name": "dgram",
"stability": 3,
"stabilityText": "Stable",
"desc": "<p>Datagram sockets are available through <code>require('dgram')</code>.\n\n</p>\n<p>Important note: the behavior of <code>dgram.Socket#bind()</code> has changed in v0.10\nand is always asynchronous now. If you have code that looks like this:\n\n</p>\n<pre><code>var s = dgram.createSocket('udp4');\ns.bind(1234);\ns.addMembership('224.0.0.114');</code></pre>\n<p>You have to change it to this:\n\n</p>\n<pre><code>var s = dgram.createSocket('udp4');\ns.bind(1234, function() {\n s.addMembership('224.0.0.114');\n});</code></pre>\n",
"methods": [
{
"textRaw": "dgram.createSocket(type, [callback])",
"type": "method",
"name": "createSocket",
"signatures": [
{
"return": {
"textRaw": "Returns: Socket object ",
"name": "return",
"desc": "Socket object"
},
"params": [
{
"textRaw": "`type` String. Either 'udp4' or 'udp6' ",
"name": "type",
"desc": "String. Either 'udp4' or 'udp6'"
},
{
"textRaw": "`callback` Function. Attached as a listener to `message` events. Optional ",
"name": "callback",
"optional": true,
"desc": "Function. Attached as a listener to `message` events."
}
]
},
{
"params": [
{
"name": "type"
},
{
"name": "callback",
"optional": true
}
]
}
],
"desc": "<p>Creates a datagram Socket of the specified types. Valid types are <code>udp4</code>\nand <code>udp6</code>.\n\n</p>\n<p>Takes an optional callback which is added as a listener for <code>message</code> events.\n\n</p>\n<p>Call <code>socket.bind</code> if you want to receive datagrams. <code>socket.bind()</code> will bind\nto the "all interfaces" address on a random port (it does the right thing for\nboth <code>udp4</code> and <code>udp6</code> sockets). You can then retrieve the address and port\nwith <code>socket.address().address</code> and <code>socket.address().port</code>.\n\n</p>\n"
}
],
"classes": [
{
"textRaw": "Class: dgram.Socket",
"type": "class",
"name": "dgram.Socket",
"desc": "<p>The dgram Socket class encapsulates the datagram functionality. It\nshould be created via <code>dgram.createSocket(type, [callback])</code>.\n\n</p>\n",
"events": [
{
"textRaw": "Event: 'message'",
"type": "event",
"name": "message",
"params": [],
"desc": "<p>Emitted when a new datagram is available on a socket. <code>msg</code> is a <code>Buffer</code> and <code>rinfo</code> is\nan object with the sender's address information and the number of bytes in the datagram.\n\n</p>\n"
},
{
"textRaw": "Event: 'listening'",
"type": "event",
"name": "listening",
"desc": "<p>Emitted when a socket starts listening for datagrams. This happens as soon as UDP sockets\nare created.\n\n</p>\n",
"params": []
},
{
"textRaw": "Event: 'close'",
"type": "event",
"name": "close",
"desc": "<p>Emitted when a socket is closed with <code>close()</code>. No new <code>message</code> events will be emitted\non this socket.\n\n</p>\n",
"params": []
},
{
"textRaw": "Event: 'error'",
"type": "event",
"name": "error",
"params": [],
"desc": "<p>Emitted when an error occurs.\n\n</p>\n"
}
],
"methods": [
{
"textRaw": "socket.send(buf, offset, length, port, address, [callback])",
"type": "method",
"name": "send",
"signatures": [
{
"params": [
{
"textRaw": "`buf` Buffer object. Message to be sent ",
"name": "buf",
"desc": "Buffer object. Message to be sent"
},
{
"textRaw": "`offset` Integer. Offset in the buffer where the message starts. ",
"name": "offset",
"desc": "Integer. Offset in the buffer where the message starts."
},
{
"textRaw": "`length` Integer. Number of bytes in the message. ",
"name": "length",
"desc": "Integer. Number of bytes in the message."
},
{
"textRaw": "`port` Integer. destination port ",
"name": "port",
"desc": "Integer. destination port"
},
{
"textRaw": "`address` String. destination IP ",
"name": "address",
"desc": "String. destination IP"
},
{
"textRaw": "`callback` Function. Callback when message is done being delivered. Optional. ",
"name": "callback",
"desc": "Function. Callback when message is done being delivered. Optional.",
"optional": true
}
]
},
{
"params": [
{
"name": "buf"
},
{
"name": "offset"
},
{
"name": "length"
},
{
"name": "port"
},
{
"name": "address"
},
{
"name": "callback",
"optional": true
}
]
}
],
"desc": "<p>For UDP sockets, the destination port and IP address must be specified. A string\nmay be supplied for the <code>address</code> parameter, and it will be resolved with DNS. An\noptional callback may be specified to detect any DNS errors and when <code>buf</code> may be\nre-used. Note that DNS lookups will delay the time that a send takes place, at\nleast until the next tick. The only way to know for sure that a send has taken place\nis to use the callback.\n\n</p>\n<p>If the socket has not been previously bound with a call to <code>bind</code>, it's\nassigned a random port number and bound to the "all interfaces" address\n(0.0.0.0 for <code>udp4</code> sockets, ::0 for <code>udp6</code> sockets).\n\n</p>\n<p>Example of sending a UDP packet to a random port on <code>localhost</code>;\n\n</p>\n<pre><code>var dgram = require('dgram');\nvar message = new Buffer("Some bytes");\nvar client = dgram.createSocket("udp4");\nclient.send(message, 0, message.length, 41234, "localhost", function(err, bytes) {\n client.close();\n});</code></pre>\n<p><strong>A Note about UDP datagram size</strong>\n\n</p>\n<p>The maximum size of an <code>IPv4/v6</code> datagram depends on the <code>MTU</code> (<em>Maximum Transmission Unit</em>)\nand on the <code>Payload Length</code> field size.\n\n</p>\n<ul>\n<li><p>The <code>Payload Length</code> field is <code>16 bits</code> wide, which means that a normal payload\ncannot be larger than 64K octets including internet header and data\n(65,507 bytes = 65,535 − 8 bytes UDP header − 20 bytes IP header);\nthis is generally true for loopback interfaces, but such long datagrams\nare impractical for most hosts and networks.</p>\n</li>\n<li><p>The <code>MTU</code> is the largest size a given link layer technology can support for datagrams.\nFor any link, <code>IPv4</code> mandates a minimum <code>MTU</code> of <code>68</code> octets, while the recommended <code>MTU</code>\nfor IPv4 is <code>576</code> (typically recommended as the <code>MTU</code> for dial-up type applications),\nwhether they arrive whole or in fragments.</p>\n<p>For <code>IPv6</code>, the minimum <code>MTU</code> is <code>1280</code> octets, however, the mandatory minimum\nfragment reassembly buffer size is <code>1500</code> octets.\nThe value of <code>68</code> octets is very small, since most current link layer technologies have\na minimum <code>MTU</code> of <code>1500</code> (like Ethernet).</p>\n</li>\n</ul>\n<p>Note that it's impossible to know in advance the MTU of each link through which\na packet might travel, and that generally sending a datagram greater than\nthe (receiver) <code>MTU</code> won't work (the packet gets silently dropped, without\ninforming the source that the data did not reach its intended recipient).\n\n</p>\n"
},
{
"textRaw": "socket.bind(port, [address], [callback])",
"type": "method",
"name": "bind",
"signatures": [
{
"params": [
{
"textRaw": "`port` Integer ",
"name": "port",
"desc": "Integer"
},
{
"textRaw": "`address` String, Optional ",
"name": "address",
"optional": true,
"desc": "String"
},
{
"textRaw": "`callback` Function, Optional ",
"name": "callback",
"optional": true,
"desc": "Function"
}
]
},
{
"params": [
{
"name": "port"
},
{
"name": "address",
"optional": true
},
{
"name": "callback",
"optional": true
}
]
}
],
"desc": "<p>For UDP sockets, listen for datagrams on a named <code>port</code> and optional <code>address</code>.\nIf <code>address</code> is not specified, the OS will try to listen on all addresses.\n\n</p>\n<p>The <code>callback</code> argument, if provided, is added as a one-shot <code>'listening'</code>\nevent listener.\n\n</p>\n<p>Example of a UDP server listening on port 41234:\n\n</p>\n<pre><code>var dgram = require("dgram");\n\nvar server = dgram.createSocket("udp4");\n\nserver.on("message", function (msg, rinfo) {\n console.log("server got: " + msg + " from " +\n rinfo.address + ":" + rinfo.port);\n});\n\nserver.on("listening", function () {\n var address = server.address();\n console.log("server listening " +\n address.address + ":" + address.port);\n});\n\nserver.bind(41234);\n// server listening 0.0.0.0:41234</code></pre>\n"
},
{
"textRaw": "socket.close()",
"type": "method",
"name": "close",
"desc": "<p>Close the underlying socket and stop listening for data on it.\n\n</p>\n",
"signatures": [
{
"params": []
}
]
},
{
"textRaw": "socket.address()",
"type": "method",
"name": "address",
"desc": "<p>Returns an object containing the address information for a socket. For UDP sockets,\nthis object will contain <code>address</code> , <code>family</code> and <code>port</code>.\n\n</p>\n",
"signatures": [
{
"params": []
}
]
},
{
"textRaw": "socket.setBroadcast(flag)",
"type": "method",
"name": "setBroadcast",
"signatures": [
{
"params": [
{
"textRaw": "`flag` Boolean ",
"name": "flag",
"desc": "Boolean"
}
]
},
{
"params": [
{
"name": "flag"
}
]
}
],
"desc": "<p>Sets or clears the <code>SO_BROADCAST</code> socket option. When this option is set, UDP packets\nmay be sent to a local interface's broadcast address.\n\n</p>\n"
},
{
"textRaw": "socket.setTTL(ttl)",
"type": "method",
"name": "setTTL",
"signatures": [
{
"params": [
{
"textRaw": "`ttl` Integer ",
"name": "ttl",
"desc": "Integer"
}
]
},
{
"params": [
{
"name": "ttl"
}
]
}
],
"desc": "<p>Sets the <code>IP_TTL</code> socket option. TTL stands for "Time to Live," but in this context it\nspecifies the number of IP hops that a packet is allowed to go through. Each router or\ngateway that forwards a packet decrements the TTL. If the TTL is decremented to 0 by a\nrouter, it will not be forwarded. Changing TTL values is typically done for network\nprobes or when multicasting.\n\n</p>\n<p>The argument to <code>setTTL()</code> is a number of hops between 1 and 255. The default on most\nsystems is 64.\n\n</p>\n"
},
{
"textRaw": "socket.setMulticastTTL(ttl)",
"type": "method",
"name": "setMulticastTTL",
"signatures": [
{
"params": [
{
"textRaw": "`ttl` Integer ",
"name": "ttl",
"desc": "Integer"
}
]
},
{
"params": [
{
"name": "ttl"
}
]
}
],
"desc": "<p>Sets the <code>IP_MULTICAST_TTL</code> socket option. TTL stands for "Time to Live," but in this\ncontext it specifies the number of IP hops that a packet is allowed to go through,\nspecifically for multicast traffic. Each router or gateway that forwards a packet\ndecrements the TTL. If the TTL is decremented to 0 by a router, it will not be forwarded.\n\n</p>\n<p>The argument to <code>setMulticastTTL()</code> is a number of hops between 0 and 255. The default on most\nsystems is 1.\n\n</p>\n"
},
{
"textRaw": "socket.setMulticastLoopback(flag)",
"type": "method",
"name": "setMulticastLoopback",
"signatures": [
{
"params": [
{
"textRaw": "`flag` Boolean ",
"name": "flag",
"desc": "Boolean"
}
]
},
{
"params": [
{
"name": "flag"
}
]
}
],
"desc": "<p>Sets or clears the <code>IP_MULTICAST_LOOP</code> socket option. When this option is set, multicast\npackets will also be received on the local interface.\n\n</p>\n"
},
{
"textRaw": "socket.addMembership(multicastAddress, [multicastInterface])",
"type": "method",
"name": "addMembership",
"signatures": [
{
"params": [
{
"textRaw": "`multicastAddress` String ",
"name": "multicastAddress",
"desc": "String"
},
{
"textRaw": "`multicastInterface` String, Optional ",
"name": "multicastInterface",
"optional": true,
"desc": "String"
}
]
},
{
"params": [
{
"name": "multicastAddress"
},
{
"name": "multicastInterface",
"optional": true
}
]
}
],
"desc": "<p>Tells the kernel to join a multicast group with <code>IP_ADD_MEMBERSHIP</code> socket option.\n\n</p>\n<p>If <code>multicastInterface</code> is not specified, the OS will try to add membership to all valid\ninterfaces.\n\n</p>\n"
},
{
"textRaw": "socket.dropMembership(multicastAddress, [multicastInterface])",
"type": "method",
"name": "dropMembership",
"signatures": [
{
"params": [
{
"textRaw": "`multicastAddress` String ",
"name": "multicastAddress",
"desc": "String"
},
{
"textRaw": "`multicastInterface` String, Optional ",
"name": "multicastInterface",
"optional": true,
"desc": "String"
}
]
},
{
"params": [
{
"name": "multicastAddress"
},
{
"name": "multicastInterface",
"optional": true
}
]
}
],
"desc": "<p>Opposite of <code>addMembership</code> - tells the kernel to leave a multicast group with\n<code>IP_DROP_MEMBERSHIP</code> socket option. This is automatically called by the kernel\nwhen the socket is closed or process terminates, so most apps will never need to call\nthis.\n\n</p>\n<p>If <code>multicastInterface</code> is not specified, the OS will try to drop membership to all valid\ninterfaces.\n\n</p>\n"
},
{
"textRaw": "socket.unref()",
"type": "method",
"name": "unref",
"desc": "<p>Calling <code>unref</code> on a socket will allow the program to exit if this is the only\nactive socket in the event system. If the socket is already <code>unref</code>d calling\n<code>unref</code> again will have no effect.\n\n</p>\n",
"signatures": [
{
"params": []
}
]
},
{
"textRaw": "socket.ref()",
"type": "method",
"name": "ref",
"desc": "<p>Opposite of <code>unref</code>, calling <code>ref</code> on a previously <code>unref</code>d socket will <em>not</em>\nlet the program exit if it's the only socket left (the default behavior). If\nthe socket is <code>ref</code>d calling <code>ref</code> again will have no effect.\n</p>\n",
"signatures": [
{
"params": []
}
]
}
]
}
],
"type": "module",
"displayName": "dgram"
}
]
}
Mini Shell