The class design of Rocket consists of one or more listener threads, a connection monitor, a threadpool and the worker threads that the threadpool manages.
There is a listener thread for each socket Rocket listens on. Each thread handles setup of its socket and enters into a connection accept loop. Once it has accepted a connection, it puts it in the active queue to be processed by a worker.
The connection monitor collects connections that are in-between requests but not closed. Whenever a worker is waiting for a new request, it will timeout if no new request comes in. Upon this timeout, the worker will send this connection to the connection monitor and move on to process another request. The connection monitor puts the received connection in a set of connections to listen on. As soon as there is activity on the listened socket, the connection monitor will put the connection back in the active queue to be processed by a worker. In the event that timeout is reached for any given connection, that connection will be closed.
The ThreadPool manages how many active worker threads there are at a given time. When constructed by the Listener (prior to the listener entering its main loop), the ThreadPool creates min_threads number of Worker threads. The number of threads varies from min_threads to max_threads based on how many requests are waiting in the active queue. If the number of active threads is greater than min_threads and the active queue is empty, Threadpool will reduce the number of active threads slowly until the number of active threads is equal to min_threads. See the section on Architecture Considerations for more information about how to use this.
The Worker class grabs a connection from the active queue and processes it until either the client signals to close the connection or the connection times out waiting for a new request. In the former case, the Worker finishes the request and closes the connection. In the case of the latter, the Worker places the Connection on the monitor queue for the Connection Monitor to watch for activity. In both cases, it then grabs another request from the active queue and starts the process over.
The Worker class is the class to inherit from when extending Rocket. While Worker provides basic functions such as reading headers and request lines, Worker is not equipped to fully process any one request. For this reason, Worker must be sub-classed for each request handling method. For example the WSGIWorker subclass extends Worker to create a valid WSGI environment and pass it on to a supplied WSGI application.
The Connection class wraps a socket connection and provides a buffered file-like interface to the socket. It also remembers useful information like if this socket is secure, the creation time-stamp and other helpful information.