The argument to proc is a procedure that takes a boolean, and it can be used to disable suspends (in case proc has critical regions where it should not be suspended). A true value passed to the procedure enables suspends, and #f disables suspends. Initially, suspends are allowed.
The coroutine-run procedure returns #t if coroutine’s procedure completes (or if it completed earlier), and the result is available via coroutine-result. The coroutine-run procedure returns #f if coroutine’s procedure does not complete before it is suspended after timeout-secs. If coroutine’s procedure raises an exception, then it is re-raised by coroutine-run.
When the returned procedure is applied, its arguments are queued to be passed on to f, and #<void> is immediately returned. The thread created by consumer-thread dequeues arguments and applies f to them, removing a new set of arguments from the queue only when the previous application of f has completed; if f escapes from a normal return (via an exception or a continuation), the f-applying thread terminates.
The init argument is a procedure of no arguments; if it is provided, init is called in the new thread immediately after the thread is created.
(run-server port-no conn-proc conn-timeout [ handler listen close accept accept/break]) → void? port-no : (integer-in 1 65535) conn-proc : (input-port? output-port? . -> . any) conn-timeout : (and/c real? (not/c negative?)) handler : (exn? . -> . any/c) = void
((integer-in 1 65535) (one-of/c 5) (one-of/c #t) . -> . listener?) = tcp-listen close : (listener? . -> . any) = tcp-close
accept : (listener? . ->* . (input-port? output-port?)) = tcp-accept
accept/break : (listener? . ->* . (input-port? output-port?)) = tcp-accept/enable-break
Each client connection is managed by a new custodian, and each call to conn occurs in a new thread (managed by the connection’s custodian). If the thread executing conn terminates for any reason (e.g., conn returns), the connection’s custodian is shut down. Consequently, conn need not close the ports provided to it. Breaks are enabled in the connection thread if breaks are enabled when run-server is called.
To facilitate capturing a continuation in one connection thread and invoking it in another, the parameterization of the run-server call is used for every call to handler. In this parameterization and for the connection’s thread, the current-custodian parameter is assigned to the connection’s custodian.
If conn-timeout is not #f, then it must be a non-negative number specifying the time in seconds that a connection thread is allowed to run before it is sent a break signal. Then, if the thread runs longer than (* conn-timeout 2) seconds, then the connection’s custodian is shut down. If conn-timeout is #f, a connection thread can run indefinitely.
If handler is provided, it is passed exceptions related to connections (i.e., exceptions not caught by conn-proc, or exceptions that occur when trying to accept a connection). The default handler ignores the exception and returns #<void>.
The run-server function uses listen, close, accept and accept/break in the same way as it might use tcp-listen, tcp-close, tcp-accept, and tcp-accept/enable-break to accept connections. Provide alternate procedures to use an alternate communication protocol (such as SSL) or to supply optional arguments in the use of tcp-listen. The listener? part of the contract indicates that the procedures must all work on the same kind of listener value.
The run-server procedure loops to serve client connections, so it never returns. If a break occurs, the loop will cleanly shut down the server, but it will not terminate active connections.