dgram: send() can accept strings

Strings passed to Socket#send() will be passed to Buffer and parsed as
UTF8.

doc/api/dgram.markdown

@@ -74,7 +74,7 @@ Emitted when an error occurs.
 
 ### socket.send(buf, offset, length, port, address, [callback])
 
-* `buf` Buffer object.  Message to be sent
+* `buf` Buffer object or string.  Message to be sent
 * `offset` Integer. Offset in the buffer where the message starts.
 * `length` Integer. Number of bytes in the message.
 * `port` Integer. destination port
@@ -93,6 +93,11 @@ If the socket has not been previously bound with a call to `bind`, it's
 assigned a random port number and bound to the "all interfaces" address
 (0.0.0.0 for `udp4` sockets, ::0 for `udp6` sockets).
 
+With consideration for multi-byte characters, `offset` and `length` will
+be calculated with respect to
+[byte length](buffer.html#buffer_class_method_buffer_bytelength_string_encoding)
+and not the character position.
+
 Example of sending a UDP packet to a random port on `localhost`;
 
     var dgram = require('dgram');

lib/dgram.js

@@ -235,8 +235,11 @@ Socket.prototype.send = function(buffer,
                                  callback) {
   var self = this;
 
+  if (util.isString(buffer))
+    buffer = new Buffer(buffer);
+
   if (!util.isBuffer(buffer))
-    throw new TypeError('First argument must be a buffer object.');
+    throw new TypeError('First argument must be a buffer or string.');
 
   offset = offset | 0;
   if (offset < 0)

test/simple/test-dgram-oob-buffer.js

@@ -48,5 +48,14 @@ assert.throws(function() {
 assert.throws(function() {
   socket.send(buf, 4, 4, common.PORT, '127.0.0.1', assert.fail);
 });
+assert.throws(function() {
+  socket.send('abc', 4, 1, common.PORT, '127.0.0.1', assert.fail);
+});
+assert.throws(function() {
+  socket.send('abc', 0, 4, common.PORT, '127.0.0.1', assert.fail);
+});
+assert.throws(function() {
+  socket.send('abc', -1, 2, common.PORT, '127.0.0.1', assert.fail);
+});
 
 socket.close(); // FIXME should not be necessary

test/simple/test-dgram-regress-4496.js

@@ -27,6 +27,6 @@ var dgram = require('dgram');
 
 // Should throw but not crash.
 var socket = dgram.createSocket('udp4');
-assert.throws(function() { socket.send('BAM', 0, 1, 1, 'host') }, TypeError);
-assert.throws(function() { socket.sendto('BAM', 0, 1, 1, 'host') }, TypeError);
+assert.throws(function() { socket.send(true, 0, 1, 1, 'host') }, TypeError);
+assert.throws(function() { socket.sendto(5, 0, 1, 1, 'host') }, TypeError);
 socket.close();

test/simple/test-dgram-udp4.js

@@ -25,11 +25,10 @@
 var common = require('../common');
 var assert = require('assert');
 
-var Buffer = require('buffer').Buffer,
-    fs = require('fs'),
+var fs = require('fs'),
     dgram = require('dgram'), server, client,
     server_port = 20989,
-    message_to_send = new Buffer('A message to send'),
+    message_to_send = 'A message to send',
     timer;
 
 server = dgram.createSocket('udp4');