Issue with conecting via websocket (Sec-WebSocket-Protocol unsuported)

renenucci

Hi!

I'm currently using the Lightstreamer version 6.0.3 (& 6.0.1), and, when I try to connect using websockets, following the TLCP Specifications document, but got 403 and an message in log's file.

I tried with bellow command:

JS Command:
var websocket = new WebSocket('ws://localhost:8080/lightstreamer',['Sec-WebSocket-Protocol','TLCP-2.1.0.lightstreamer.com']);

Result: 403

LS Server Log:
02-abr-20 10:03:00,578|WARN |ightstreamerLogger.connections.WS|SERVER POOLED THREAD 10 |Received websocket upgrade request with no acceptable subprotocol: unsupported.

Tried the same with currently online server (latest version of LS) wss://push.lightstreamer.com/lighstreamer and works like a charm.

The question is, wich subprotocol should I use with version 6.0.1 (&6.0.3) to work with websockets transport? I have not found any documentation about this.

Thanks!

Dario Crivelli

You are right, there is no resuming document on the relations between TLCP versions and Server versions.
The relevant information is in the changelog of the related SDK (the SDK for Generic Clients), that you can find in the download page.
The (currently) latest changelog follows the whole story of the protocol.

In practice,

SDK (i.e. TLCP) version 2.1.0 is compatible with the Server since Server version 7.0.
SDK (i.e. TLCP) version 2.0.0 is compatible with the Server since Server version 6.1.

2.0.0 is also the first version of the TLCP protocol. The previous versions of the SDK were not based on the TLCP protocol, but on a totally different protocol, with even a different versioning. In particular, we see that

SDK version 6.0.3 is compatible with the Server since Server version 6.0.3.
SDK version 6.0.1 is compatible with the Server since Server version 6.0.

It is also implicitly said that every new version of the Server keeps the support for all SDK versions supported by the previous one.

The documentation of each protocol version can be found in the "Lightstreamer/DOCS-SDKs/sdk_client_generic/doc" folder of the distribution package in which it was released and, obviously, it is compatible with the Server version available in the same distribution package.
The protocol for SDK version 6.0.3 can also be found here.