Error code 61 with error message "Malformed message received"

stian

I am running Lightstreamer 7.4.7 on our servers for streaming updates to our users. We have been doing this for a number of years. Our clients are React applications using the javascript client library.

This week one of our users got the Error code 61 with the error message "Malformed message received" from the onServerError callback. We are unable to reproduce the issue and I am at a loss of how to debug the problem. Is there a way to find out which message is malformed and in what way?

The documentation for the onServerError is good enough, but it doesn't really help me figure out what is happening. https://lightstreamer.com/sdks/ls-nodejs-client/9.2.2/api/ClientListener.html#onServerError

Thanks for any input!

Giuseppe Corti

stian
Unfortunately, the error message "Malformed message received" (Error Code 61) is quite generic, making it difficult to pinpoint the exact root cause without more information.
This error can occur in two situations:

When a message originating from the server is not recognized by the client library.
When an unexpected exception is raised while the client is processing an otherwise recognized message.

A plausible—though speculative—hypothesis for both cases is that the message reaching the client was corrupted somehow during transmission, rendering it unrecognizable or malformed during processing.
If we had the client library debug log, we could identify the specific message that triggered error 61. However, I understand this is not feasible if the issue is not reproducible in a consistent way.

As a side note, based on the format of the error message, it seems that you may not be using the latest version of the client library. I don’t believe this is directly related to the problem, but we always recommend keeping the client libraries updated.