guix-devel/build-aux/download.scm

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Scheme

;;; Guix --- Nix package management from Guile. -*- coding: utf-8 -*-
;;; 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/>.
;;;
;;; Download a binary file from an external source.
;;;
(use-modules (ice-9 match)
(web uri)
(web client)
(rnrs io ports)
(srfi srfi-11)
(guix utils))
(define %url-base
"http://www.fdn.fr/~lcourtes/software/guix/packages")
(define (file-name->uri file)
"Return the URI for FILE."
(match (string-tokenize file (char-set-complement (char-set #\/)))
((_ ... system basename)
(string->uri (string-append %url-base "/" system "/" basename)))))
(match (command-line)
((_ file expected-hash)
(let ((uri (file-name->uri file)))
(format #t "downloading file `~a' from `~a'...~%"
file (uri->string uri))
(let*-values (((resp data) (http-get uri #:decode-body? #f))
((hash) (bytevector->base16-string (sha256 data)))
((part) (string-append file ".part")))
(if (string=? expected-hash hash)
(begin
(call-with-output-file part
(lambda (port)
(put-bytevector port data)))
(rename-file part file))
(begin
(format (current-error-port)
"file at `~a' has SHA256 ~a; expected ~a~%"
(uri->string uri) hash expected-hash)
(exit 1)))))))