net: cleanup connect logic

Separates out the lookup logic for net.Socket. In the event the `host` property is an IP address, the lookup is skipped. PR-URL: #1505 Reviewed-By: Chris Dickinson <[email protected]> Reviewed-By: Yosuke Furukawa <[email protected]>

Author: evanlucas

lib/net.js

@@ -881,64 +881,77 @@ Socket.prototype.connect = function(options, cb){
 connect(self,options.path);
 
 }else{
-constdns=require('dns');
-varhost=options.host||'localhost';
-varport=0;
-varlocalAddress=options.localAddress;
-varlocalPort=options.localPort;
-vardnsopts={
-family: options.family,
-hints: 0
-};
-
-if(localAddress&&!exports.isIP(localAddress))
-thrownewTypeError('localAddress must be a valid IP: '+localAddress);
-
-if(localPort&&typeoflocalPort!=='number')
-thrownewTypeError('localPort should be a number: '+localPort);
-
-port=options.port;
-if(typeofport!=='undefined'){
-if(typeofport!=='number'&&typeofport!=='string')
-thrownewTypeError('port should be a number or string: '+port);
-if(!isLegalPort(port))
-thrownewRangeError('port should be >= 0 and < 65536: '+port);
-}
-port|=0;
+lookupAndConnect(self,options);
+}
+returnself;
+};
 
-if(dnsopts.family!==4&&dnsopts.family!==6)
-dnsopts.hints=dns.ADDRCONFIG|dns.V4MAPPED;
 
-debug('connect: find host '+host);
-debug('connect: dns options '+dnsopts);
-self._host=host;
-dns.lookup(host,dnsopts,function(err,ip,addressType){
-self.emit('lookup',err,ip,addressType);
+functionlookupAndConnect(self,options){
+constdns=require('dns');
+varhost=options.host||'localhost';
+varport=options.port;
+varlocalAddress=options.localAddress;
+varlocalPort=options.localPort;
 
-// It's possible we were destroyed while looking this up.
-// XXX it would be great if we could cancel the promise returned by
-// the look up.
-if(!self._connecting)return;
+if(localAddress&&!exports.isIP(localAddress))
+thrownewTypeError('localAddress must be a valid IP: '+localAddress);
 
-if(err){
-// net.createConnection() creates a net.Socket object and
-// immediately calls net.Socket.connect() on it (that's us).
-// There are no event listeners registered yet so defer the
-// error event to the next tick.
-process.nextTick(connectErrorNT,self,err,options);
-}else{
-self._unrefTimer();
-connect(self,
-ip,
-port,
-addressType,
-localAddress,
-localPort);
-}
-});
+if(localPort&&typeoflocalPort!=='number')
+thrownewTypeError('localPort should be a number: '+localPort);
+
+if(typeofport!=='undefined'){
+if(typeofport!=='number'&&typeofport!=='string')
+thrownewTypeError('port should be a number or string: '+port);
+if(!isLegalPort(port))
+thrownewRangeError('port should be >= 0 and < 65536: '+port);
 }
-returnself;
-};
+port|=0;
+
+// If host is an IP, skip performing a lookup
+// TODO(evanlucas) should we hot path this for localhost?
+varaddressType=exports.isIP(host);
+if(addressType){
+connect(self,host,port,addressType,localAddress,localPort);
+return;
+}
+
+vardnsopts={
+family: options.family,
+hints: 0
+};
+
+if(dnsopts.family!==4&&dnsopts.family!==6)
+dnsopts.hints=dns.ADDRCONFIG|dns.V4MAPPED;
+
+debug('connect: find host '+host);
+debug('connect: dns options '+dnsopts);
+self._host=host;
+dns.lookup(host,dnsopts,function(err,ip,addressType){
+self.emit('lookup',err,ip,addressType);
+
+// It's possible we were destroyed while looking this up.
+// XXX it would be great if we could cancel the promise returned by
+// the look up.
+if(!self._connecting)return;
+
+if(err){
+// net.createConnection() creates a net.Socket object and
+// immediately calls net.Socket.connect() on it (that's us).
+// There are no event listeners registered yet so defer the
+// error event to the next tick.
+process.nextTick(connectErrorNT,self,err,options);
+}else{
+self._unrefTimer();
+connect(self,
+ip,
+port,
+addressType,
+localAddress,
+localPort);
+}
+});
+}
 
 
 functionconnectErrorNT(self,err,options){

test/parallel/test-net-dns-lookup-skip.js

@@ -0,0 +1,18 @@
+varcommon=require('../common');
+varassert=require('assert');
+varnet=require('net');
+
+functioncheck(addressType){
+varserver=net.createServer(function(client){
+client.end();
+server.close();
+});
+
+varaddress=addressType===4 ? '127.0.0.1' : '::1';
+server.listen(common.PORT,address,function(){
+net.connect(common.PORT,address).on('lookup',assert.fail);
+});
+}
+
+check(4);
+common.hasIPv6&&check(6);

test/parallel/test-net-dns-lookup.js

@@ -9,7 +9,7 @@ var server = net.createServer(function(client){
 });
 
 server.listen(common.PORT,'127.0.0.1',function(){
-net.connect(common.PORT,'127.0.0.1').on('lookup',function(err,ip,type){
+net.connect(common.PORT,'localhost').on('lookup',function(err,ip,type){
 assert.equal(err,null);
 assert.equal(ip,'127.0.0.1');
 assert.equal(type,'4');