Node.js and postgres LISTEN

Question

I want to use Heroku, PostgreSQL and Node.js and set it up so that anytime I add an entry to my postgres Node.js database, it will dump the contents of this line to the console.

I am trying to configure it as indicated:
http://lheurt.blogspot.com/2011/11/listen-to-postgresql-inserts-with.html
http://bjorngylling.com/2011-04-13/postgres-listen-notify-with-node-js.html

here is the Node.js code

var pg = require('pg'); conString = '/*my database connection*/'; var client = new pg.Client(conString); client.connect(function(err) { if(err) { return console.error('could not connect to postgres', err); } client.connect(); client.query('LISTEN "loc_update"'); client.on('notification', function(data) { console.log(data.payload); }); }); 

Here is the function executed in the postgres database

  String function = "CREATE FUNCTION notify_trigger() RETURNS trigger AS $$ " + "DECLARE " + "BEGIN " + "PERFORM pg_notify('loc_update', TG_TABLE_NAME || ',longitude,' || NEW.longitude || ',latitude,' || NEW.latitude );" + "RETURN new;" + "END;" + "$$ LANGUAGE plpgsql;"; String trigger = "CREATE TRIGGER location_update AFTER INSERT ON device " + "FOR EACH ROW EXECUTE PROCEDURE notify_trigger();"; 

After uploading to Heroku, I get this error. What am I doing wrong?

 2013-10-13T22:40:21.470310+00:00 heroku[web.1]: Starting process with command `node web.js` 2013-10-13T22:40:23.697134+00:00 app[web.1]: 2013-10-13T22:40:23.727555+00:00 app[web.1]: events.js:72 2013-10-13T22:40:23.727822+00:00 app[web.1]: throw er; // Unhandled 'error' event 2013-10-13T22:40:23.727822+00:00 app[web.1]: ^ 2013-10-13T22:40:23.784576+00:00 app[web.1]: error: invalid frontend message type 0 2013-10-13T22:40:23.784576+00:00 app[web.1]: at p.parseE (/app/node_modules/pg/lib/connection.js:473:11) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at p.parseMessage (/app/node_modules/pg/lib/connection.js:348:17) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at Socket.<anonymous> (/app/node_modules/pg/lib/connection.js:84:22) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at Socket.EventEmitter.emit (events.js:117:20) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at Socket.<anonymous> (_stream_readable.js:746:14) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at Socket.EventEmitter.emit (events.js:92:17) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at emitReadable_ (_stream_readable.js:408:10) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at emitReadable (_stream_readable.js:404:5) 2013-10-13T22:40:23.784576+00:00 app[web.1]: at readableAddChunk (_stream_readable.js:165:9) 2013-10-13T22:40:23.784787+00:00 app[web.1]: at Socket.Readable.push (_stream_readable.js:127:10) 2013-10-13T22:40:25.128299+00:00 heroku[web.1]: Process exited with status 8 2013-10-13T22:40:25.133342+00:00 heroku[web.1]: State changed from starting to crashed 

Answer 1

try renaming the variable:

 String function = "CREATE FUNCTION notify_trigger() RETURNS trigger AS $$ "; 

to

 String variableFunction = "CREATE FUNCTION notify_trigger() RETURNS trigger AS $$ "; 

Function

- reserved word.

If the error persists, try to simulate the same environment on the local host.