Please help! Can't open websocket, and Error during WebSocket handshake: Unexpected response code: 400

[Ashley Wang]

Hi all,

I have a small TornadoServer app that opens websockets as soon as the webpage is loaded. This worked perfectly locally, but once I deployed it to production, the websockets returned the error:

WebSocket connection to 'wss://query2logs.default.abattery.appbattery.nss1.tn.akamai.com/socket/' failed: Error during WebSocket handshake: Unexpected response code: 400

On the server side, in the logs, there's this error: "WARNING:tornado.access:400 GET /socket/ (127.0.0.1) 0.29ms

The code that creates the problem is in a js file, which runs on the client side:

function open_websocket(relative_path) {

var new_uri;

if (location.protocol == "https:") {

new_uri = "wss:";

} else { //could this be dangerous?

new_uri = "ws:";

}

new_uri += "//" + location.host;

if (relative_path.startsWith("/")) {

new_uri += relative_path;

} else {

if (pathname.endsWith("/")) { //NOTE: all my URLs will hit this, but we write both kinds for completeness

new_uri += loc.pathname + relative_path; 

} else {

new_uri += loc.pathname + "/" + relative_path;

}

}

return new WebSocket(new_uri);

}

In the server side, the socket open() method never runs.

Any help would be greatly appreciated! I am completely stuck on this.

[Ben Darnell]

Searching for "400" in https://github.com/tornadoweb/tornado/blob/master/tornado/websocket.py shows that this response code is used when the "Upgrade: websocket" or "Connection: upgrade" headers are not present. Is akamai passing these headers along? Does the akamai product/configuration you're using support websockets on this url? 

-Ben

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[Ashley Wang]

Hi! Thanks so much!

The error happens before I make a request.

When I do make a request with these headers, the error I get is:  

requests.exceptions.ConnectionError: ('Connection aborted.', error(111, 'Connection refused'))

One difference is that, in production, the url is a https isntead of http. As a result, I'm trying to open a websocket with 'wss' instead of 'ws'. I didn't think this would be an issue though, and either way I can't change the production url to 'http'.

akamai is passing the headers along and it does support websockets. I've tested it before on other akamai machines and there was no problem.

[Ben Darnell]

On Fri, Aug 7, 2015 at 11:41 AM, Ashley Wang <liah....@gmail.com> wrote:

Hi! Thanks so much!

The error happens before I make a request.

When I do make a request with these headers, the error I get is:  

requests.exceptions.ConnectionError: ('Connection aborted.', error(111, 'Connection refused'))

You can't use an HTTP client to make a request with these headers; the purpose of these headers is to tell the server that you're using a websocket client instead of an HTTP client. 

 

One difference is that, in production, the url is a https isntead of http. As a result, I'm trying to open a websocket with 'wss' instead of 'ws'. I didn't think this would be an issue though, and either way I can't change the production url to 'http'.

I don't think that's the issue; if it were you wouldn't even be getting a 400 back.

 

akamai is passing the headers along and it does support websockets. I've tested it before on other akamai machines and there was no problem.

Unfortunately I don't have much to add. It looks to me like the problem is somewhere in the akamai layer but I have no idea what's going on there. How do you know that akamai is passing the headers along? Do you have packet captures?

-Ben