Socket.IO detection of client's browser sometimes failing

Question

I am working on a real time tracking application that uses Node.js and Socket.IO. In my tracking code that goes on a target site I have some code that grabs the user agent string of the browser and sends it back to the server. This USUALLY works fine but there are a few times where this data is set to undefined (this is where it happens).

For now, I just have a huge try/catch block on the server so it doesn't crash when running a method I've defined to detect what browser it is (it crashes when it tries to run the match() method). I'm assuming this is happening either from bots or from some other browser that has no user agent or has been tampered with. Am I wrong on that? Are there other reasons?

Does Socket.IO provide anything for browser detection? Either way I know I need to make the browser detection feature more robust but I'm just getting this project off the ground.

If there's no better way to do this, am I better off just checking to see if the data that was sent to the server is undefined and consider it as an "Other" browser?

See the difference in total connections and total browser numbers? At the moment, there's a difference of a little over 100. If this browser tracking issue wasn't happening the numbers should be exactly the same (because EVERY connection would have a browser, resolution, operating system, and a URL).

Answer 1

This actually had nothing to do with bots or tampered data like I thought it did. My problem was due to a rare race condition where the client would connect to the server but disconnect before sending the data to the server (the "beacon" event I have set up is where the client sends the data and the server receives it). So when the client went to disconnect, my server would look up the client but would return a undefined result because the data was never sent and stored in the first place. A rewarding experience but what a pain!