add heartbeat

Author: NumminorihSF

lib/client.js

@@ -25,7 +25,8 @@ var Client = function(config) {
 
   this.connection = c.connection || new Connection({
     stream: c.stream,
-    ssl: this.connectionParameters.ssl
+    ssl: this.connectionParameters.ssl,
+    heartbeat: this.connectionParameters.heartbeatInterval
   });
   this.queryQueue = [];
   this.binary = c.binary || defaults.binary;

lib/connection-parameters.js

@@ -48,6 +48,8 @@ var ConnectionParameters = function(config) {
 
   this.application_name = val('application_name', config, 'PGAPPNAME');
   this.fallback_application_name = val('fallback_application_name', config, false);
+
+  this.heartbeatInterval = parseInt(val('heartbeat_interval', config), 10);
 };
 
 var add = function(params, config, paramName) {

lib/connection.js

@@ -26,6 +26,9 @@ var Connection = function(config) {
     headerSize: 1,
     lengthPadding: -4
   });
+  this._heartbeatEnable = !!config.heartbeat;
+  this._heartbeatInterval = Number(config.heartbeat);
+  this._heartbeatObject = null;
   var self = this;
   this.on('newListener', function(eventName) {
     if(eventName == 'message') {
@@ -48,6 +51,16 @@ Connection.prototype.connect = function(port, host) {
 
   this.stream.on('connect', function() {
     self.emit('connect');
+    if (self._heartbeatEnable) {
+      self._heartbeatObject = setInterval(function() {
+        self.stream.write('', function (err) {
+          if (err) {
+            clearInterval(self._heartbeatObject);
+            self.emit('error', err);
+          }
+        })
+      }, self._heartbeatInterval);
+    }
   });
 
   this.stream.on('error', function(error) {
@@ -56,13 +69,15 @@ Connection.prototype.connect = function(port, host) {
     if(self._ending && error.code == 'ECONNRESET') {
       return;
     }
+    clearInterval(self._heartbeatObject);
     self.emit('error', error);
   });
 
   this.stream.on('close', function() {
     // NOTE: node-0.10 emits both 'end' and 'close'
     //       for streams closed by the peer, while
     //       node-0.8 only emits 'close'
+    clearInterval(self._heartbeatObject);
     self.emit('end');
   });
 

lib/defaults.js

@@ -41,7 +41,11 @@ var defaults = module.exports = {
   ssl: false,
 
   application_name : undefined,
-  fallback_application_name: undefined
+  fallback_application_name: undefined,
+
+  //heartbeat interval to check, that socket is alive. if 0 - heartbeat is disabled (for backward capability).
+  //else - timeout in ms.
+  heartbeat_interval: 0
 };
 
 //parse int8 so you can get your count values as actual numbers