guix/guix-download.in

#!/bin/sh
# aside from this initial boilerplate, this is actually -*- scheme -*- code

prefix="@prefix@"
datarootdir="@datarootdir@"

GUILE_LOAD_COMPILED_PATH="@guilemoduledir@:$GUILE_LOAD_COMPILED_PATH"
export GUILE_LOAD_COMPILED_PATH

main='(module-ref (resolve-interface '\''(guix-download)) '\'guix-download')'
exec ${GUILE-@GUILE@} -L "@guilemoduledir@" -l "$0"    \
         -c "(apply $main (cdr (command-line)))" "$@"
!#
;;; Guix --- Nix package management from Guile.
;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of Guix.
;;;
;;; Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix-download)
  #:use-module (web uri)
  #:use-module (web client)
  #:use-module (web response)
  #:use-module (guix ui)
  #:use-module (guix store)
  #:use-module (guix utils)
  #:use-module (guix base32)
  #:use-module (guix ftp-client)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-37)
  #:use-module (rnrs bytevectors)
  #:use-module (rnrs io ports)
  #:export (guix-download))

(define (call-with-temporary-output-file proc)
  (let* ((template (string-copy "guix-download.XXXXXX"))
         (out      (mkstemp! template)))
    (dynamic-wind
      (lambda ()
        #t)
      (lambda ()
        (proc template out))
      (lambda ()
        (false-if-exception (delete-file template))))))

(define (http-fetch url port)
  "Fetch from URL over HTTP and write the result to PORT."
  (let*-values (((response data) (http-get url #:decode-body? #f))
                ((code) (response-code response)))
    (if (= code 200)
        (put-bytevector port data)
        (leave (_ "failed to download from `~a': ~a: ~a~%")
               (uri->string url)
               code (response-reason-phrase response)))))

(define (ftp-fetch url port)
  "Fetch from URL over FTP and write the result to PORT."
  (let* ((conn (ftp-open (uri-host url)
                         (or (uri-port url) 21)))
         (dir  (dirname (uri-path url)))
         (file (basename (uri-path url)))
         (in   (ftp-retr conn file dir)))
    (define len 65536)
    (define buffer
      (make-bytevector len))

    (let loop ((count (get-bytevector-n! in buffer 0 len)))
      (if (eof-object? count)
          (ftp-close conn)
          (begin
            (put-bytevector port buffer 0 count)
            (loop (get-bytevector-n! in buffer 0 len)))))))


;;;
;;; Command-line options.
;;;

(define %default-options
  ;; Alist of default option values.
  `((format . ,bytevector->nix-base32-string)))

(define (show-help)
  (display (_ "Usage: guix-download [OPTION]... URL
Download the file at URL, add it to the store, and print its store path
and the hash of its contents.\n"))
  (format #t (_ "
  -f, --format=FMT       write the hash in the given format (default: `nix-base32')"))
  (newline)
  (display (_ "
  -h, --help             display this help and exit"))
  (display (_ "
  -V, --version          display version information and exit"))
  (newline)
  (format #t (_ "
Report bugs to: ~a.~%") "@PACKAGE_BUGREPORT@"))

(define %options
  ;; Specifications of the command-line options.
  (list (option '(#\f "format") #t #f
                (lambda (opt name arg result)
                  (define fmt-proc
                    (match arg
                      ("nix-base32"
                       bytevector->nix-base32-string)
                      ("base32"
                       bytevector->base32-string)
                      ((or "base16" "hex" "hexadecimal")
                       bytevector->base16-string)
                      (x
                       (format (current-error-port)
                               "unsupported hash format: ~a~%" arg))))

                  (alist-cons 'format fmt-proc
                              (alist-delete 'format result))))

        (option '(#\h "help") #f #f
                (lambda args
                  (show-help)
                  (exit 0)))
        (option '(#\V "version") #f #f
                (lambda args
                  (show-version-and-exit "guix-download")))))


;;;
;;; Entry point.
;;;

(define (guix-download . args)
  (define (parse-options)
    ;; Return the alist of option values.
    (args-fold args %options
               (lambda (opt name arg result)
                 (leave (_ "~A: unrecognized option~%") name))
               (lambda (arg result)
                 (alist-cons 'argument arg result))
               %default-options))

  (setlocale LC_ALL "")
  (textdomain "guix")
  (setvbuf (current-output-port) _IOLBF)
  (setvbuf (current-error-port) _IOLBF)

  (let* ((opts  (parse-options))
         (store (open-connection))
         (uri   (string->uri (assq-ref opts 'argument)))
         (fetch (case (uri-scheme uri)
                  ((http) http-fetch)
                  ((ftp)  ftp-fetch)
                  (else
                   (begin
                     (format (current-error-port)
                             (_ "guix-download: ~a: unsupported URI scheme~%")
                             (uri-scheme uri))
                     (exit 1)))))
         (path  (call-with-temporary-output-file
                 (lambda (name port)
                   (fetch uri port)
                   (close port)
                   (add-to-store store (basename (uri-path uri))
                                 #t #f "sha256" name))))
         (hash  (call-with-input-file path
                  (compose sha256 get-bytevector-all)))
         (fmt   (assq-ref opts 'format)))
    (format #t "~a~%~a~%" path (fmt hash))
    #t))