JavaScript client CONNECTED:HTTP-STREAMING status during 'sync error'

jnuckolls

Hello,

I'm using the JavaScript client to connect to a production light streamer server. Occasionally there is a sync error and the subscription needs to be remade. This is fine, but the issue is that the JavaScript client never fires an event and the status remains as "CONNECTED:HTTP-STREAMING" despite the fact that when checking the "Network" tab I can see sync errors being returned by the server.

The server response looks like:

/*window.LS_lastError = {};
window.LS_lastError[1] = "sync error";


*/

I've tried hooking into all of the events in the Server-sent errors section of the client documentation but am still not getting anything telling me the client is in an error state.

any help is much appreciated. Thanks.

Alessandro.Carioni

Hi,

A sync error is usually generated when, in the interval between the sending of a request (e.g. a subscription) and the processing by the server, the session has changed. This interval is generally very short but in some unpredictable circumstances (e.g. a slow network or a server with a high load) it can span several seconds. Anyway this is not an issue because the Javascript client is able to enact recovery actions which are totally transparent to user (you noticed them because you looked at the network traffic).

On the other hand there is a situation where the sync error is the signal of a true problem, that is when the session has NOT changed recently. In this case you should notice a serious malfunctioning on the client, such as not receiving any data.

Are you experiencing a similar behavior? In order to further investigate, can you send us excerpts from the server log (the log should register the events occurring a few seconds before and after the sync error)? This would be of great help because otherwise we should relay only on the client log.

Regards