Title

Author

Abstract

Status

This SRFI is currently in ``draft'' status. To see an explanation of each status that a SRFI can hold, see here. To provide input on this SRFI, please mail to <srfi minus 106 at srfi dot schemers dot org>. See instructions here to subscribe to the list. You can access previous messages via the archive of the mailing list.

• Received: 2012/08/29
• Draft: 2012/10/07-2012/12/07

Issues

• The constants variables' names are taken from POSIX, should this be renamed?
• At least how many constant variables should this SRFI support?

Rationale

Many Scheme implementation have its own socket APIs however there are no portable way to write socket program. Therefore programmers need to provide implementation dependent layer for their program.

This document specifies a uniform interface to write socket programming. That should make it easier to write portable programs that need to send or receive data from their socket.

Specification

Constructors and predicate

      make-client-socket make-server-socket socket?
    

Socket operations

      socket-accept socket-send socket-recv
      socket-shutdown socket-close
    

Port conversion

      socket-port
    

Control feature

      call-with-socket
    

Constant values

      AF_UNSPEC AF_INET AF_INET6
      SOCK_STREAM SOCK_DGRAM
      AI_PASSIVE AI_CANONNAME AI_NUMERICHOST
      AI_V4MAPPED AI_ALL AI_ADDRCONFIG
      SHUT_RD SHUT_WR SHUT_RDWR
    

The procedures

Constructors and predicate

make-client-socket node service [ai-family [ai-socktype [ai-flags [ai-protocol]]]] -> socket

Returns a client socket connected to an Internet addres.

The Internet address is identified by node and service. node and service must be string.

Example value of node: "localhost" "127.0.0.1"

Example value of service: "http" "80"

The optional parameter may specify the created socket's behaviour.

make-server-socket service [ai-family [ai-socktype [ai-protocol]]] -> socket

Returns a server socket waiting for connection.

The description of node argument is the same as make-client-socket.

The optional parameter may specify the created socket's behaviour.

socket? object -> boolean

Returns #t if given object is socket object. Otherwise #f.

Socket operations

socket-accept socket -> socket

Wait for an incomming connection request, and returns a fresh connected client socket.

socket-send socket bv [flags] -> size

Sends a binary data block to a socket and returns the sent data size.

flags may specify the procedure's behaviour.

socket-recv socket size [flags] -> bv

Receives a binary data block from a socket.

flags may specify the procedure's behaviour.

socket-shutdown socket how -> (unspeficied)

Shutdows a socket.

how must be one of the following constants;

• SHUT_RD
• SHUT_WR
• SHUT_RDWR

socket-close socket -> (unspeficied)

Closes a socket.

Port conversion

socket-port socket -> binary-input/output-port

Returns a fresh binary input/output port associated with a socket.

Control feature

call-with-socket socket proc -> object

Calls a given procedure with a given socket as an argument.

Constants

• AF_UNSPEC
• AF_INET
• AF_INET6
• SOCK_STREAM
• SOCK_DGRAM
• AI_PASSIVE
• AI_CANONNAME
• AI_NUMERICHOST
• AI_V4MAPPED
• AI_ALL
• AI_ADDRCONFIG
• SHUT_RD
• SHUT_WR
• SHUT_RDWR

Example

(import (rnrs) (socket))

(define echo-server-socket (make-server-socket "5000"))

(define (server-run)
  (define (get-line-from-binary-port bin)
    (utf8->string
     (call-with-bytevector-output-port
      (lambda (out)
        (let loop ((b (get-u8 bin)))
          (case b
            ((#xA) #t) ;; newline
            ((#xD) (loop (get-u8 bin))) ;; carriage return
            (else (put-u8 out b) (loop (get-u8 bin))))))))
  (let ((addr (socket-accept echo-server-socket)))
    (call-with-socket
     addr
     (lambda (sock)
       (let ((p (socket-port sock)))
         (call-with-port
          p
          (lambda (p)
            (let lp2 ((r (get-line-from-binary-port p)))
              (put-bytevector p (string->utf8 (string-append r "\r\n"))
              (lp2 (get-line-from-binary-port p))))))))))
(server-run)

Implementation

Interface layer

(library (socket)
    (export make-client-socket make-server-socket
       	    socket? socket-port call-with-socket
       	    socket-accept socket-send socket-recv socket-shutdown socket-close
       	    AF_UNSPEC AF_INET AF_INET6
       	    SOCK_STREAM SOCK_DGRAM
       	    AI_PASSIVE AI_CANONNAME AI_NUMERICHOST
       	    AI_V4MAPPED AI_ALL AI_ADDRCONFIG
       	    SHUT_RD SHUT_WR SHUT_RDWR)
    (import (socket impl)))

Implementation dependent layer

For Ypsilon

(library (socket impl)
    (export make-client-socket make-server-socket
            socket? socket-port call-with-socket
            socket-accept socket-send socket-recv socket-shutdown socket-close
            AF_UNSPEC AF_INET AF_INET6
            SOCK_STREAM SOCK_DGRAM
            AI_PASSIVE AI_CANONNAME AI_NUMERICHOST
            AI_V4MAPPED AI_ALL AI_ADDRCONFIG
            SHUT_RD SHUT_WR SHUT_RDWR)
    (import (rnrs) (rename (ypsilon socket)
                           (socket-send %socket-send)
                           (socket-recv %socket-recv)))

  (define (socket-send socket bv . flags)
    (let ((flags (if (null? flags) 0 (car flags))))
      (%socket-send socket bv flags)))

  (define (socket-recv socket size . flags)
    (let ((flags (if (null? flags) 0 (car flags))))
      (%socket-recv socket size flags)))
)

For Mosh

(library (socket impl)
    (export make-client-socket make-server-socket
            socket? socket-port call-with-socket
            socket-accept socket-send socket-recv socket-shutdown socket-close
            AF_UNSPEC AF_INET AF_INET6
            SOCK_STREAM SOCK_DGRAM
            AI_PASSIVE AI_CANONNAME AI_NUMERICHOST
            AI_V4MAPPED AI_ALL AI_ADDRCONFIG
            SHUT_RD SHUT_WR SHUT_RDWR)
    (import (mosh socket))

For Sagittarius

(library (socket impl)
    (export make-client-socket make-server-socket
            socket? socket-port call-with-socket
            socket-accept socket-send socket-recv socket-shutdown socket-close
            AF_UNSPEC AF_INET AF_INET6
            SOCK_STREAM SOCK_DGRAM
            AI_PASSIVE AI_CANONNAME AI_NUMERICHOST
            AI_V4MAPPED AI_ALL AI_ADDRCONFIG
            SHUT_RD SHUT_WR SHUT_RDWR)
    (import (rnrs) (rename (sagittarius socket)
                           (socket-send %socket-send)
                           (socket-recv %socket-recv)))

  (define (socket-send socket bv :optional (flags 0))
    (%socket-send socket bv flags))

  (define (socket-recv socket size :optional (flags 0))
    (%socket-recv socket size flags))
  )

For others

(library (socket impl)
    (export make-client-socket make-server-socket
            socket? socket-port call-with-socket
            socket-accept socket-send socket-recv socket-shutdown socket-close
            AF_UNSPEC AF_INET AF_INET6
            SOCK_STREAM SOCK_DGRAM
            AI_PASSIVE AI_CANONNAME AI_NUMERICHOST
            AI_V4MAPPED AI_ALL AI_ADDRCONFIG
            SHUT_RD SHUT_WR SHUT_RDWR)
    (import (rnrs))

  (define-syntax define-unsupported
    (syntax-rules ()
      ((_ (name))
       (define (name . _)
         (raise 
          (condition (make-implementation-restriction-violation)
                     (make-who-condition 'name)
                     (make-message-condition
                      "This SRFI is not supported on this implementation")))))
      ((_ name)
       (define name #f))))

  (define-unsupported (make-client-socket))
  (define-unsupported (make-server-socket))
  (define-unsupported (socket?           ))
  (define-unsupported (socket-port       ))
  (define-unsupported (call-with-socket  ))
  (define-unsupported (socket-accept     ))
  (define-unsupported (socket-send       ))
  (define-unsupported (socket-recv       ))
  (define-unsupported (socket-shutdown   ))
  (define-unsupported (socket-close      ))

  (define-unsupported AF_UNSPEC     )
  (define-unsupported AF_INET       )
  (define-unsupported AF_INET6      )
  (define-unsupported SOCK_STREAM   )
  (define-unsupported SOCK_DGRAM    )
  (define-unsupported AI_PASSIVE    )
  (define-unsupported AI_CANONNAME  )
  (define-unsupported AI_NUMERICHOST)
  (define-unsupported AI_V4MAPPED   )
  (define-unsupported AI_ALL        )
  (define-unsupported AI_ADDRCONFIG )

  (define-unsupported SHUT_RD)
  (define-unsupported SHUT_WR)
  (define-unsupported SHUT_RDWR))

Copyright

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.