> but the framework author certainly had to deal with thread safety
usually not. if your framework builds off the common web integration system for the target environment, i.e. Java Servlets, WSGI in Python, etc., you're already handed a request scope within a thread. It's only web servers and containers that really have a heavy lifting job to do.
To be fair, though, Django is not thread safe. Now while I respect Rails for taking the effort in making it thread safe (IIRC, it was a Google Summer of Code project) - it doesn't seem to be a must-have to have your framework be thread safe.
usually not. if your framework builds off the common web integration system for the target environment, i.e. Java Servlets, WSGI in Python, etc., you're already handed a request scope within a thread. It's only web servers and containers that really have a heavy lifting job to do.