chibi-scheme/lib/chibi/net.scm
2011-05-23 03:31:24 -07:00

49 lines
2 KiB
Scheme

;; Copyright (c) 2010-2011 Alex Shinn. All rights reserved.
;; BSD-style license: http://synthcode.com/license.txt
;;> Opens a client net connection to @var{host}, a string,
;;> on port @var{service}, which can be a string such as
;;> @scheme{"http"} or an integer. Returns a list of two
;;> values on success - an input port and output port -
;;> or @scheme{#f} on failure.
(define (open-net-io host service)
(let lp ((addr (get-address-info host
(if (integer? service)
(number->string service)
service)
#f)))
(if (not addr)
(error "couldn't find address" host service)
(let ((sock (socket (address-info-family addr)
(address-info-socket-type addr)
(address-info-protocol addr))))
(if (negative? sock)
(lp (address-info-next addr))
(cond
((negative?
(connect sock
(address-info-address addr)
(address-info-address-length addr)))
(lp (address-info-next addr)))
(else
(cond-expand
(threads (set-file-descriptor-flags! sock open/non-block))
(else #f))
(list (open-input-file-descriptor sock)
(open-output-file-descriptor sock)))))))))
;;> Convenience wrapper around @scheme{open-net-io}, opens
;;> the connection then calls @var{proc} with two arguments,
;;> the input port and the output port connected to the
;;> service, then closes the connection. Returns the result
;;> of @var{proc}. Raises an error if a connection can't
;;> be made.
(define (with-net-io host service proc)
(let ((io (open-net-io host service)))
(if (not (pair? io))
(error "couldn't find address" host service)
(let ((res (proc (car io) (car (cdr io)))))
(close-input-port (car io))
res))))