I have this web app written with express and socket.io using node.js, the app works brillantly on localhost, but when i push to my ec2 server, it connects for like 20 seconds then disconnects, and then connects again etc...

giving me the error on the node console as

warn  - websocket connection invalid
info  - transport end

SERVER

app = express()
server = http.createServer(app)
io = require('socket.io').listen(server)

CLIENT

socket = io.connect()

I know the problem is not with my code, because I fully tested the web app on localhost, so the only problem is where this code is running, which is my ec2 instance?

I have this web app written with express and socket.io using node.js, the app works brillantly on localhost, but when i push to my ec2 server, it connects for like 20 seconds then disconnects, and then connects again etc...

giving me the error on the node console as

warn  - websocket connection invalid
info  - transport end

SERVER

app = express()
server = http.createServer(app)
io = require('socket.io').listen(server)

CLIENT

socket = io.connect()

I know the problem is not with my code, because I fully tested the web app on localhost, so the only problem is where this code is running, which is my ec2 instance?

• javascript
• node.js
• sockets
• websocket
• socket.io

• do you connect to the instance directly or via an ELB ? – Tommaso Barbugli Commented Apr 25, 2013 at 8:32
• i connect directly to the instance? – unknown Commented Apr 25, 2013 at 10:58
• can anyone answer this question, its really bugging me sireously! – unknown Commented Apr 27, 2013 at 8:13
• 2 your question does not give enough details. please post relevant server code. maybe your code breaks when deployed on ec2. – user568109 Commented Apr 27, 2013 at 18:39
• Can the app municate (send messages back and forth) during those 20 seconds? If not, it's probably a simple firewall issue. Or maybe socket.io has dropped into polling mode because you have a non-websocket webserver in front. – BraveNewCurrency Commented May 3, 2013 at 14:55

4 Answers 4

There could be many possible reasons you can get this error:

1. You are using browser that partially or does not support websockets. You can check if your browser supports websockets here.
2. Using proxy that does not support websocket. If there is some server(load balancer) between your client and your node server that does not support websocket.
3. You are using socket.io version 0.9.1/0.9.1-1. This behaviour is a reported bug for this version. So upgrade to latest socket.io version which is 0.9.14.
4. Browser connectivity is firewalled/blocked.
5. Code related problem.

Make sure you're using latest versions of node, express and socket.io on your ec2. Also, provide some data about currently used versions both on your local machine and on ec2 instance.

Running on your local machine you don't have to deal with network latency, NAT issues, or firewalls. Running on EC2 you have all of those.

Web Sockets are relatively new and unstable. So to begin with be sure you're running the latest versions (and let us know what they are). Perhaps the version of socket.io installed on your local machine is different than the version installed in your EC2 server.

If there is no activity during those 20 seconds before losing the connection, one possibility is that keep-alive is set too low.

See https://groups.google./forum/?fromgroups=#!topic/socket_io/RUv70BguZ-U for a similar problem. The solution there was to use heartbeat to keep the connection open.

A bit more on socket.io heartbeats if you're not already using them: Advantage/disadvantage of using socketio heartbeats