Mirror of GNU Guix
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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
;;; This file is part of GNU Guix.
;;; GNU 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.
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; GNU General Public License for more details.
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix web)
#:use-module (web uri)
#:use-module (web client)
#:use-module (web response)
#:use-module (srfi srfi-11)
#:use-module (rnrs io ports)
#:use-module (rnrs bytevectors)
#:use-module (guix ui)
#:use-module (guix utils)
#:export (http-fetch))
;;; Commentary:
;;; Web client portable among Guile versions.
;;; Code:
(define* (http-fetch uri #:key (text? #f))
"Return an input port containing the data at URI, and the expected number of
bytes available or #f. If TEXT? is true, the data at URI is considered to be
textual. Follow any HTTP redirection."
(let loop ((uri uri))
(let*-values (((resp data)
;; Try hard to use the API du jour to get an input port.
;; On Guile 2.0.5 and before, we can only get a string or
;; bytevector, and not an input port. Work around that.
(if (version>? "2.0.7" (version))
(if (defined? 'http-get*)
(http-get* uri #:decode-body? text?) ; 2.0.7
(http-get uri #:decode-body? text?)) ; 2.0.5-
(http-get uri #:streaming? #t))) ; 2.0.9+
(response-code resp)))
(case code
(let ((len (response-content-length resp)))
(cond ((not data)
;; XXX: Guile 2.0.5 and earlier did not support chunked
;; transfer encoding, which is required for instance when
;; fetching %PACKAGE-LIST-URL (see
;; <http://lists.gnu.org/archive/html/guile-devel/2011-09/msg00089.html>).
;; Since users may still be using these versions, warn them
;; and bail out.
(warning (_ "using Guile ~a, ~a ~s encoding~%")
"which does not support HTTP"
(response-transfer-encoding resp))
(leave (_ "download failed; use a newer Guile~%")
uri resp)))
((string? data) ; `http-get' from 2.0.5-
(values (open-input-string data) len))
((bytevector? data) ; likewise
(values (open-bytevector-input-port data) len))
(else ; input port
(values data len)))))
((301 ; moved permanently
302) ; found (redirection)
(let ((uri (response-location resp)))
(format #t "following redirection to `~a'...~%"
(uri->string uri))
(loop uri)))
(error "download failed" uri code
(response-reason-phrase resp)))))))
;;; web.scm ends here