support for connecting via hostname with native bindings (using node async dns lookup instead of sync libpq dns)

lib/native.js

@@ -12,7 +12,8 @@ var nativeConnect = p.connect;
 
 p.connect = function() {
   var self = this;
-  getLibpgConString(this._config, function(conString) {
+  utils.buildLibpqConnectionString(this._config, function(err, conString) {
+    if(err) return self.emit('error', err);
     nativeConnect.call(self, conString);
   })
 }
@@ -121,7 +122,7 @@ var NativeQuery = function(text, values, callback) {
       if(item instanceof Date) {
         this.values[i] = JSON.stringify(item);
       } else {
-        this.values[i] = item.toString();        
+        this.values[i] = item.toString();
       }
     }
   }
@@ -167,40 +168,11 @@ p.handleReadyForQuery = function() {
   this.emit('end');
 };
 
-var add = function(params, config, paramName) {
-  var value = config[paramName];
-  if(value) {
-    params.push(paramName+"='"+value+"'");
-  }
-}
-
-//connection string helper
-var getLibpgConString = function(config, callback) {
-  if(typeof config == 'object') {
-    var params = []
-    add(params, config, 'user');
-    add(params, config, 'password');
-    add(params, config, 'port');
-    if(config.database) {
-      params.push("dbname='" + config.database + "'");
-    }
-    if(config.host) {
-      if(config.host != 'localhost' && config.host != '127.0.0.1') {
-        throw new Error("Need to use node to do async DNS on host");
-      }
-      params.push("hostaddr=127.0.0.1 ");
-    }
-    callback(params.join(" "));
-  } else {
-    throw new Error("Unrecognized config type for connection");
-  }
-}
-
 var pool = require(__dirname + '/client-pool').init(ctor);
 
 module.exports = {
   Client: ctor,
   connect: pool.connect,
   end: pool.end,
-  defaults: require(__dirname + '/defaults')
+  defaults: require(__dirname + '/defaults')  
 };

lib/utils.js

@@ -116,7 +116,49 @@ var normalizeConnectionInfo = function(config) {
   }
 };
 
+
+var add = function(params, config, paramName) {
+  var value = config[paramName];
+  if(value) {
+    params.push(paramName+"='"+value+"'");
+  }
+}
+
+//builds libpq specific connection string
+//from a supplied config object 
+//the config object conforms to the interface of the config object
+//accepted by the pure javascript client
+var getLibpgConString = function(config, callback) {
+  if(typeof config == 'object') {
+    var params = []
+    add(params, config, 'user');
+    add(params, config, 'password');
+    add(params, config, 'port');
+    if(config.database) {
+      params.push("dbname='" + config.database + "'");
+    }
+    if(config.host) {
+      if(config.host != 'localhost' && config.host != '127.0.0.1') {
+        //do dns lookup
+        return require('dns').lookup(config.host, 4, function(err, address) {
+          if(err) return callback(err, null);
+          params.push("hostaddr="+address)
+          callback(null, params.join(" "))
+        })
+      }
+      params.push("hostaddr=127.0.0.1 ");
+    }
+    callback(null, params.join(" "));
+  } else {
+    throw new Error("Unrecognized config type for connection");
+  }
+}
+
 module.exports = {
   Pool: Pool,
-  normalizeConnectionInfo: normalizeConnectionInfo
+  normalizeConnectionInfo: normalizeConnectionInfo,
+  //only exported here to make testing of this method possible
+  //since it contains quite a bit of logic and testing for
+  //each connection scenario in an integration test is impractical
+  buildLibpqConnectionString: getLibpgConString
 }

test/integration/client/error-handling-tests.js

@@ -85,3 +85,13 @@ test('error handling', function(){
   });
 
 });
+
+test('when connecting to invalid host', function() {
+  var client = new Client({
+    user: 'brian',
+    password: '1234',
+    host: 'asldkfjasdf!!#1308140.com'
+  })
+  assert.emits(client, 'error');
+  client.connect();
+})

test/unit/utils-tests.js

@@ -187,3 +187,56 @@ test('normalizing connection info', function() {
     })
   })
 })
+
+test('libpq connection string building', function() {
+  var checkForPart = function(array, part) {
+    assert.ok(array.indexOf(part) > -1, array.join(" ") + " did not contain " + part);
+  }
+
+  test('builds simple string', function() {
+    var config = {
+      user: 'brian',
+      password: 'xyz',
+      port: 888,
+      host: 'localhost',
+      database: 'bam'
+    }
+    utils.buildLibpqConnectionString(config, assert.calls(function(err, constring) {
+      assert.isNull(err)
+      var parts = constring.split(" ");
+      checkForPart(parts, "user='brian'")
+      checkForPart(parts, "password='xyz'")
+      checkForPart(parts, "port='888'")
+      checkForPart(parts, "hostaddr=127.0.0.1")
+      checkForPart(parts, "dbname='bam'")
+    }))
+  })
+  test('builds dns string', function() {
+    var config = {
+      user: 'brian',
+      password: 'asdf',
+      port: 5432,
+      host: 'example.com'
+    }
+    utils.buildLibpqConnectionString(config, assert.calls(function(err, constring) {
+      assert.isNull(err);
+      var parts = constring.split(" ");
+      checkForPart(parts, "user='brian'")
+      checkForPart(parts, "hostaddr=192.0.32.10")
+    }))
+  })
+
+  test('error when dns fails', function() {
+    var config = {
+      user: 'brian',
+      password: 'asf',
+      port: 5432,
+      host: 'asdlfkjasldfkksfd#!$!!!!..com'
+    }
+    utils.buildLibpqConnectionString(config, assert.calls(function(err, constring) {
+      assert.ok(err);
+      assert.isNull(constring)
+    }))
+  })
+
+})