option to send only ID field in notifications

Author: epoberezkin

index.js

@@ -19,14 +19,16 @@ var DEFAULTS = {
         removeNotifyTrigger: 'remove_notify_trigger_to_table'
     },
     operationEvents: true,
-    checkUpdates: true // only notify if update changes record, can be set to false if record comparison is expensive
+    checkUpdates: true, // only notify if update changes record, can be set to false if record comparison is expensive
+    sendRecordId: false // send only record IDs, true - to send column 'id', string to send column with a given name
 };
 
 function PGObserver (opts) {
     if (!(this instanceof PGObserver)) return new PGObserver(opts);
     this.client = opts.client || new pg.Client(opts.conString);
     if (opts.names) opts.names = _.extend(_.clone(DEFAULTS.names), opts.names);
     opts = _.extend(_.clone(DEFAULTS), opts);
+    if (opts.sendRecordId === true) opts.sendRecordId = 'id';
     this.options = opts;
 };
 

install.sql

@@ -12,12 +12,15 @@ BEGIN
       "operation": "' || TG_OP || '",
       "timestamp": "' || CURRENT_TIMESTAMP || '"';
 
+  {{ var id = it.sendRecordId; }}
   IF TG_OP = 'INSERT' OR TG_OP = 'UPDATE' THEN
-    data := data || ', "data": ' || row_to_json(NEW);
+    data := data || ', "data": ' ||
+      {{?id}} '{ "{{=id}}": ' || NEW.{{=id}}::text || ' }'; {{??}} row_to_json(NEW); {{?}}
   END IF;
 
   IF TG_OP = 'DELETE' OR TG_OP = 'UPDATE' THEN
-    data := data || ', "old_data": ' || row_to_json(OLD);
+    data := data || ', "old_data": ' ||
+      {{?id}} '{ "{{=id}}": ' || OLD.{{=id}}::text || ' }'; {{??}} row_to_json(OLD); {{?}}
   END IF;
 
   data := data || '}';

readme.md

@@ -27,6 +27,10 @@ var dispatcher = require('pg-dispatch')({
     // },
     // operationEvents: true, // false to NOT send events on each operation
     // checkUpdates: true // only notify if update changes record
+    // sendRecordId: false // send only record IDs, true - to send column 'id',
+                           // string to send column with a given name.
+                           // this column should be a number.
+                           // by default the whole record data is sent.
 });
 
 dispatcher.install(function(err) {

tests/setup.sql

@@ -1,6 +1,6 @@
 DROP TABLE IF EXISTS users;
 CREATE TABLE IF NOT EXISTS users(
-	user_id serial primary key,
+	id serial primary key,
 	name varchar(80),
 	created_at timestamp not null default now()
 );

tests/tests.js

@@ -1,6 +1,6 @@
 var assert = require('assert')
 var pg = require('pg')
-var PGEvents = require('../')
+var PGEvents = require('../index')
 var connect = require('./connect')
 
 before(function (done) {
@@ -74,7 +74,6 @@ describe('PG Events', function() {
           validCache(self.cache);
           assert.equal(self.cache.operation, 'UPDATE');
           assert.notDeepEqual(self.cache.old_data, {}, 'cache old_data is empty');
-          self.cache = {};
 
           done();
         }, 100);
@@ -83,6 +82,7 @@ describe('PG Events', function() {
 
     it('should not send message when no changes', function(done) {
       var self = this;
+      this.cache = {};
       this.client.query("UPDATE users SET name='cat' WHERE name='cat'", function (error) {
         if (error) return done(error);