dns: rename domain to hostname

A follow-up commit will save the domain name on the request object but
we can't call that property 'domain' because that gets intercepted by
src/node.cc and lib/domain.js to implement the node.js feature of the
same name.

To avoid confusion, rename all variables called 'domain' to 'hostname'.

doc/api/dns.markdown

@@ -21,19 +21,19 @@ resolves the IP addresses which are returned.
       console.log('addresses: ' + JSON.stringify(addresses));
 
       addresses.forEach(function (a) {
-        dns.reverse(a, function (err, domains) {
+        dns.reverse(a, function (err, hostnames) {
           if (err) {
             throw err;
           }
 
-          console.log('reverse for ' + a + ': ' + JSON.stringify(domains));
+          console.log('reverse for ' + a + ': ' + JSON.stringify(hostnames));
         });
       });
     });
 
-## dns.lookup(domain, [family], callback)
+## dns.lookup(hostname, [family], callback)
 
-Resolves a domain (e.g. `'google.com'`) into the first found A (IPv4) or
+Resolves a hostname (e.g. `'google.com'`) into the first found A (IPv4) or
 AAAA (IPv6) record.
 The `family` can be the integer `4` or `6`. Defaults to `null` that indicates
 both Ip v4 and v6 address family.
@@ -45,13 +45,13 @@ necessarily the value initially passed to `lookup`).
 
 On error, `err` is an `Error` object, where `err.code` is the error code.
 Keep in mind that `err.code` will be set to `'ENOENT'` not only when
-the domain does not exist but also when the lookup fails in other ways
+the hostname does not exist but also when the lookup fails in other ways
 such as no available file descriptors.
 
 
-## dns.resolve(domain, [rrtype], callback)
+## dns.resolve(hostname, [rrtype], callback)
 
-Resolves a domain (e.g. `'google.com'`) into an array of the record types
+Resolves a hostname (e.g. `'google.com'`) into an array of the record types
 specified by rrtype. Valid rrtypes are `'A'` (IPV4 addresses, default),
 `'AAAA'` (IPV6 addresses), `'MX'` (mail exchange records), `'TXT'` (text
 records), `'SRV'` (SRV records), `'PTR'` (used for reverse IP lookups),
@@ -65,54 +65,54 @@ On error, `err` is an `Error` object, where `err.code` is
 one of the error codes listed below.
 
 
-## dns.resolve4(domain, callback)
+## dns.resolve4(hostname, callback)
 
 The same as `dns.resolve()`, but only for IPv4 queries (`A` records).
 `addresses` is an array of IPv4 addresses (e.g.
 `['74.125.79.104', '74.125.79.105', '74.125.79.106']`).
 
-## dns.resolve6(domain, callback)
+## dns.resolve6(hostname, callback)
 
 The same as `dns.resolve4()` except for IPv6 queries (an `AAAA` query).
 
 
-## dns.resolveMx(domain, callback)
+## dns.resolveMx(hostname, callback)
 
 The same as `dns.resolve()`, but only for mail exchange queries (`MX` records).
 
 `addresses` is an array of MX records, each with a priority and an exchange
 attribute (e.g. `[{'priority': 10, 'exchange': 'mx.example.com'},...]`).
 
-## dns.resolveTxt(domain, callback)
+## dns.resolveTxt(hostname, callback)
 
 The same as `dns.resolve()`, but only for text queries (`TXT` records).
-`addresses` is an array of the text records available for `domain` (e.g.,
+`addresses` is an array of the text records available for `hostname` (e.g.,
 `['v=spf1 ip4:0.0.0.0 ~all']`).
 
-## dns.resolveSrv(domain, callback)
+## dns.resolveSrv(hostname, callback)
 
 The same as `dns.resolve()`, but only for service records (`SRV` records).
-`addresses` is an array of the SRV records available for `domain`. Properties
+`addresses` is an array of the SRV records available for `hostname`. Properties
 of SRV records are priority, weight, port, and name (e.g.,
 `[{'priority': 10, {'weight': 5, 'port': 21223, 'name': 'service.example.com'}, ...]`).
 
-## dns.resolveNs(domain, callback)
+## dns.resolveNs(hostname, callback)
 
 The same as `dns.resolve()`, but only for name server records (`NS` records).
-`addresses` is an array of the name server records available for `domain`
+`addresses` is an array of the name server records available for `hostname`
 (e.g., `['ns1.example.com', 'ns2.example.com']`).
 
-## dns.resolveCname(domain, callback)
+## dns.resolveCname(hostname, callback)
 
 The same as `dns.resolve()`, but only for canonical name records (`CNAME`
 records). `addresses` is an array of the canonical name records available for
-`domain` (e.g., `['bar.example.com']`).
+`hostname` (e.g., `['bar.example.com']`).
 
 ## dns.reverse(ip, callback)
 
-Reverse resolves an ip address to an array of domain names.
+Reverse resolves an ip address to an array of hostnames.
 
-The callback has arguments `(err, domains)`.
+The callback has arguments `(err, hostnames)`.
 
 On error, `err` is an `Error` object, where `err.code` is
 one of the error codes listed below.
@@ -143,7 +143,7 @@ Each DNS query can return one of the following error codes:
 - `dns.NOTIMP`: DNS server does not implement requested operation.
 - `dns.REFUSED`: DNS server refused query.
 - `dns.BADQUERY`: Misformatted DNS query.
-- `dns.BADNAME`: Misformatted domain name.
+- `dns.BADNAME`: Misformatted hostname.
 - `dns.BADFAMILY`: Unsupported address family.
 - `dns.BADRESP`: Misformatted DNS reply.
 - `dns.CONNREFUSED`: Could not contact DNS servers.
@@ -160,4 +160,3 @@ Each DNS query can return one of the following error codes:
 - `dns.LOADIPHLPAPI`: Error loading iphlpapi.dll.
 - `dns.ADDRGETNETWORKPARAMS`: Could not find GetNetworkParams function.
 - `dns.CANCELLED`: DNS query cancelled.
-

lib/dns.js

@@ -94,8 +94,8 @@ function onlookup(err, addresses) {
 
 
 // Easy DNS A/AAAA look up
-// lookup(domain, [family,] callback)
+// lookup(hostname, [family,] callback)
-exports.lookup = function(domain, family, callback) {
+exports.lookup = function(hostname, family, callback) {
   // parse arguments
   if (arguments.length === 2) {
     callback = family;
@@ -110,7 +110,7 @@ exports.lookup = function(domain, family, callback) {
   }
   callback = makeAsync(callback);
 
-  if (!domain) {
+  if (!hostname) {
     callback(null, null, family === 6 ? 6 : 4);
     return {};
   }
@@ -119,14 +119,14 @@ exports.lookup = function(domain, family, callback) {
   // localhost entry from c:\WINDOWS\system32\drivers\etc\hosts
   // See http://daniel.haxx.se/blog/2011/02/21/localhost-hack-on-windows/
   // TODO Remove this once c-ares handles this problem.
-  if (process.platform == 'win32' && domain == 'localhost') {
+  if (process.platform == 'win32' && hostname == 'localhost') {
     callback(null, '127.0.0.1', 4);
     return {};
   }
 
-  var matchedFamily = net.isIP(domain);
+  var matchedFamily = net.isIP(hostname);
   if (matchedFamily) {
-    callback(null, domain, matchedFamily);
+    callback(null, hostname, matchedFamily);
     return {};
   }
 
@@ -135,7 +135,7 @@ exports.lookup = function(domain, family, callback) {
     family: family,
     oncomplete: onlookup
   };
-  var err = cares.getaddrinfo(req, domain, family);
+  var err = cares.getaddrinfo(req, hostname, family);
   if (err) throw errnoException(err, 'getaddrinfo');
 
   callback.immediately = true;
@@ -181,7 +181,7 @@ exports.resolveNaptr = resolveMap.NAPTR = resolver('queryNaptr');
 exports.reverse = resolveMap.PTR = resolver('getHostByAddr');
 
 
-exports.resolve = function(domain, type_, callback_) {
+exports.resolve = function(hostname, type_, callback_) {
   var resolver, callback;
   if (util.isString(type_)) {
     resolver = resolveMap[type_];
@@ -192,7 +192,7 @@ exports.resolve = function(domain, type_, callback_) {
   }
 
   if (util.isFunction(resolver)) {
-    return resolver(domain, callback);
+    return resolver(hostname, callback);
   } else {
     throw new Error('Unknown type "' + type_ + '"');
   }