websocket4net connect to Java Spring WebSocket server

[jliu1970]

Hi Jerry,

Is there any way that the client can connect to Spring WebSocket server?

When I tried with a client instantiated through WebSocket(host, subprotocol, version) { I tried both an empty string and "STOMP" as subprotocol), the client state always transitioned to "Connecting", then "Close".

Thanks
Jimmy

[jliu1970]

I suspect that the Open() method needs to support STOMP's connect frame. But could not figure out a way to pass the frame to Open() method.
Thanks
Jimmy

[jliu1970]

Sorry, Kerry. I mistyped your name to Jerry in my initial message. Please advise.

Thanks
Jimmy

[kerryjiang]

Could you show me the handshake header the Spring WebSocket server required?

[jliu1970]

Kerry,

Sorry, it took me a couple of days to get back to you. The following is the capture of the "GET /cadrs/v1/websocket/infor HTTP/1.1" request. Please let me know if this is what you are looking for:

Frame 22: 239 bytes on wire (1912 bits), 239 bytes captured (1912 bits) on interface 6
Ethernet II, Src: IntelCor_68:27:93 (cc:3d:82:68:27:93), Dst: IntelCor_e1:04:3d (cc:3d:82:e1:04:3d)
Internet Protocol Version 4, Src: 10.10.29.140, Dst: 10.10.21.208
Transmission Control Protocol, Src Port: 1203, Dst Port: 8080, Seq: 1, Ack: 1, Len: 185
Hypertext Transfer Protocol
GET /cadrs/v1/websocket/info HTTP/1.1\r\n
User-Agent: Java/1.8.0-internal\r\n
Host: 10.10.21.208:8080\r\n
Accept: text/html, image/gif, image/jpeg, *; q=.2, /; q=.2\r\n
Connection: keep-alive\r\n
\r\n
[Full request URI: http://10.10.21.208:8080/cadrs/v1/websocket/info]
[HTTP request 1/1]
[Response in frame: 23]

[kerryjiang]

It doesn't like a websocket request's information.
Websocket request's uri should start with "ws://" or "wss://".

[jliu1970]

and the [Full request URL: http://10.10.21.208:8080/cadrs/v1/websocket/info] has information of: {"entropy":-1545485823,"origins":[":"],"cookie_needed":true,"websocket":true}

[jliu1970]

Following by this frame:

Frame 28: 275 bytes on wire (2200 bits), 275 bytes captured (2200 bits) on interface 6
Ethernet II, Src: IntelCor_68:27:93 (cc:3d:82:68:27:93), Dst: IntelCor_e1:04:3d (cc:3d:82:e1:04:3d)
Internet Protocol Version 4, Src: 10.10.29.140, Dst: 10.10.21.208
Transmission Control Protocol, Src Port: 1204, Dst Port: 8080, Seq: 1, Ack: 1, Len: 221
Hypertext Transfer Protocol
GET /cadrs/v1/websocket/892/2db4d4b8d20842ac9d670fb49a1bf559/websocket HTTP/1.1\r\n
Sec-WebSocket-Key: yvAIYYRPv/m+WGKebKeeDQ==\r\n
Connection: upgrade\r\n
Sec-WebSocket-Version: 13\r\n
Host: 10.10.21.208:8080\r\n
Upgrade: websocket\r\n
\r\n
[Full request URI: http://10.10.21.208:8080/cadrs/v1/websocket/892/2db4d4b8d20842ac9d670fb49a1bf559/websocket]
[HTTP request 1/1]
[Response in frame: 29]

and the [Full request URI:....] has content of "Can "Upgrade" only to "WebSocket"."
which the Spring Websocket server response with a 101.

[kerryjiang]

You can use Fiddler instead to capture the raw communication.

It still doesn't seem right:

1. the schema of websocket should be "ws://" and "wss://";
2. I cannot see any information about "STOMP".

[jliu1970]

I will try Fiddler and let you know what I get.

Thanks
Jimmy

[jliu1970]

Hi Kerry,

Please see attached for the Fiddler capture. Also, app.zip is the main test client code I used.

Thanks
Jimmy

app.zip

FiddlerCaptureWebSocket.zip

[jliu1970]

Here is a capture through Chrome.

[jliu1970]

Hi Kerry,

Please advise if my latest capture included information that you were looking for.

Thanks
Jimmy

[kerryjiang]

From the bottom of the screenshot, the server is the RabbitMQ?
If so, you have to use a RabbitMQ client instead.

[jliu1970]

Yea, it is not really intuitive. RabbitMQ really serves as a full function StompBrokerRelay component in the Spring WebSocket solution. From a client point of view, it talks to a websocket server with STOMP subprotocol.

https://www.youtube.com/watch?v=mmIza3L64Ic&feature=c4-overview&list=UU7yfnfvEUlXUIfm8rGLwZdA

Thanks
Jimmy

[kerryjiang]

Did you get any detailed error message you you tried to connect with WebSocket4Net?

Try to trace the communication when you connect using websocket4net.

[jliu1970]

Hi Kerry,

An error was received at the websocket client. Please see the image dump attached for the ErrorEventArgs.

The client constructor looks like:
WebSocket webSocketClient = new WebSocket("the server endpoint", "", WebSocketVersion.Rfc6455);

Thanks
Jimmy

[kerryjiang]

Could you use Fiddler to track this communication either?

[kgqian3910]

Hi, Kerry,

My name is Kevin Qian who is working with Jimmy on this issue. Jimmy is out of town for a week. so I can help to collect info you needed.

With fiddler, I don't even see any protocol level packet (HTTP or WS triggered by my client), while I could see in Jimmy's capture when using JS client jimmy attached.

what this link's shown seem matching what we see in JS client: https://tools.ietf.org/html/rfc6455#section-1.3

Regards,
Kevin

[kgqian3910]

I was able to fix the issue on Open() by allowing setAllowedOrigins("") on WebSocket Server side as follows:
@OverRide
public void registerStompEndpoints(StompEndpointRegistry registry) {
//registry.addEndpoint("/gs-guide-websocket").withSockJS();
//Make sure the endpoint is in sync with the CADRSWebSocketAPI doucment
registry.addEndpoint("/cadrs/v1/websocket").withSockJS(); //existing registry
registry.addEndpoint("/cadrs/v1/websocket").setAllowedOrigins(""); // newly added registry to fix
//Websocket4Net client issue
// on Open()
}
Regards,
Kevin

[kerryjiang]

If so, this issue is about origin.

Anyway, you can find what is the correct origin. And set the origin by yourself by the websocket constructor parameter.

var websocket = new WebSocket(xxxx, orgin = "correctOrgin");

[kgqian3910]

Thank you, that works!

[kgqian3910]

Hi, Kerry,

One more question for you: Now I am able to connect our Stomp Websocket Server. However, the server will close the endpoint at 30 seconds after the connection is established because the server has heartbeat enabled. Does WebSocket4Net have a way for user to turn on heartbeat? I see that user can set values for EnableAutoSendPing and AutoSendPingInterval. what are the use of these attributes? are they related to heartbeat? Do you have a heartbeat implementation example for a websocket client?

Regards,
Kevin

[kerryjiang]

Which kind heartbeat does it want?

If it is just websocket ping/pong, I think websocket4net already enable it by default.

But if it requires some kind application level heart beat, you just need send the the keep alive message following their protocol.