http_server(:Goal,
+Options)Create the server. Options must provide the 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:
- port(?Address)
- 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.
- workers(+N)
- 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.
- timeout(+SecondsOrInfinite)
- 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.
- keep_alive_timeout(+SecondsOrInfinite)
- 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.
- local(+KBytes)
- Size of the local-stack for the workers. Default is taken from the
commandline option.
- global(+KBytes)
- Size of the global-stack for the workers. Default is taken from the
commandline option.
- trail(+KBytes)
- Size of the trail-stack for the workers. Default is taken from the
commandline option.
- ssl(+SSLOptions)
- 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.
