port(?Port)option to specify the port the server should listen to. If Port is unbound an arbitrary free port is selected and Port is unified to this port-number. The server consists of a small Prolog thread accepting new connection on Port and dispatching these to a pool of workers. Defined Options are:
- Address to bind to. Address is either a port (integer) or a term Host:Port. The port may be a variable, causing the system to select a free port and unify the variable with the selected port. See also tcp_bind/2.
- Defines the number of worker threads in the pool. Default is to use five workers. Choosing the optimal value for best performance is a difficult task depending on the number of CPUs in your system and how much resources are required for processing a request. Too high numbers makes your system switch too often between threads or even swap if there is not enough memory to keep all threads in memory, while a too low number causes clients to wait unnecessary for other clients to complete. See also http_workers/2.
- Determines the maximum period of inactivity handling a request. If no
data arrives within the specified time since the last data arrived, the
connection raises an exception, and the worker discards the client and
returns to the pool-queue for a new client. If it is
infinite, a worker may wait forever on a client that doesn't complete its request. Default is 60 seconds.
- Maximum time to wait for new activity on Keep-Alive connections. Choosing the correct value for this parameter is hard. Disabling Keep-Alive is bad for performance if the clients request multiple documents for a single page. This may ---for example-- be caused by HTML frames, HTML pages with images, associated CSS files, etc. Keeping a connection open in the threaded model however prevents the thread servicing the client servicing other clients. The default is 2 seconds.
- Size of the local-stack for the workers. Default is taken from the commandline option.
- Size of the global-stack for the workers. Default is taken from the commandline option.
- Size of the trail-stack for the workers. Default is taken from the commandline option.
- Use SSL (Secure Socket Layer) rather than plain TCP/IP. A server created
this way is accessed using the
https://protocol. SSL allows for encrypted communication to avoid others from tapping the wire as well as improved authentication of client and server. The SSLOptions option list is passed to ssl_context/3. The port option of the main option list is forwarded to the SSL layer. See the
library(ssl)library for details.