Skip deserialisation if no session content

[bigpresh]

No check is made to see if any session data was actually retrieved before trying to deserialise it, leading to the following mildly irritating error in the logs:

[1078261]   (Fri Aug  9 12:19:13 2013 from unknown)
    warn @0.110656> [hit #285]Could not retrieve session ID 81841834147620443673007375773661338 - malformed JSON string, neither array, object, number, string or atom, at character offset 0 (before "(end of string)") at /opt/perlbrew/perls/perl-5.14.2/lib/site_perl/5.14.2/JSON.pm line 171. in /opt/perlbrew/perls/perl-5.14.2/lib/site_perl/5.14.2/Dancer/Session/DBI.pm l. 163

It would make sense, I think, to check whether you got any session data, and if not, bail gracefully there before attempting to deserialise.

[LoonyPandora]

The module already does this, and the warning you see is the "bailing gracefully" when the session could not be deserialized : https://github.com/LoonyPandora/Dancer-Session-DBI/blob/master/lib/Dancer/Session/DBI.pm#L187-L192

I don't think there is a more graceful way to do it.

[bigpresh]

I wonder if a warning is really necessary? Not finding a session with a given session ID will be a pretty common thing in a busy app - just people hitting the app with an expired session ID, say. Maybe it should be at debug level instead?

(Also, checking for session data before attempting to deserialize it would at least silence the JSON deserialisation part of the error, which is the scarier part which makes it sound like something is broken, rather than a routine situation being handled as designed.)

[LoonyPandora]

Hmm, yeah making it a debug level warning would be nicer. I'll get on it :)

[LoonyPandora]

Done with: https://github.com/LoonyPandora/Dancer-Session-DBI/releases/tag/v1.2.1