214 lines
8.3 KiB
Scheme
214 lines
8.3 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
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;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
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;;; Copyright © 2012, 2015 Free Software Foundation, Inc.
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;;; Copyright © 2017 Tobias Geerinckx-Rice <me@tobias.gr>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (guix http-client)
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#:use-module (web uri)
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#:use-module ((web client) #:hide (open-socket-for-uri))
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#:use-module (web response)
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#:use-module (srfi srfi-11)
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#:use-module (srfi srfi-19)
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#:use-module (srfi srfi-26)
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#:use-module (srfi srfi-34)
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#:use-module (srfi srfi-35)
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#:use-module (ice-9 match)
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#:use-module (ice-9 binary-ports)
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#:use-module (rnrs bytevectors)
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#:use-module (guix ui)
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#:use-module (guix utils)
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#:use-module (guix base64)
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#:autoload (gcrypt hash) (sha256)
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#:use-module ((guix build utils)
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#:select (mkdir-p dump-port))
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#:use-module ((guix build download)
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#:select (open-socket-for-uri
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(open-connection-for-uri
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. guix:open-connection-for-uri)
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resolve-uri-reference))
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#:re-export (open-socket-for-uri)
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#:export (&http-get-error
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http-get-error?
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http-get-error-uri
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http-get-error-code
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http-get-error-reason
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http-fetch
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%http-cache-ttl
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http-fetch/cached))
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;;; Commentary:
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;;;
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;;; HTTP client portable among Guile versions, and with proper error condition
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;;; reporting.
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;;;
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;;; Code:
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;; HTTP GET error.
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(define-condition-type &http-get-error &error
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http-get-error?
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(uri http-get-error-uri) ; URI
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(code http-get-error-code) ; integer
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(reason http-get-error-reason)) ; string
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(define* (http-fetch uri #:key port (text? #f) (buffered? #t)
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(verify-certificate? #t)
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(headers '((user-agent . "GNU Guile"))))
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"Return an input port containing the data at URI, and the expected number of
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bytes available or #f. If TEXT? is true, the data at URI is considered to be
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textual. Follow any HTTP redirection. When BUFFERED? is #f, return an
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unbuffered port, suitable for use in `filtered-port'. HEADERS is an alist of
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extra HTTP headers.
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When VERIFY-CERTIFICATE? is true, verify HTTPS server certificates.
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Raise an '&http-get-error' condition if downloading fails."
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(let loop ((uri (if (string? uri)
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(string->uri uri)
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uri)))
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(let ((port (or port (guix:open-connection-for-uri uri
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#:verify-certificate?
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verify-certificate?)))
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(headers (match (uri-userinfo uri)
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((? string? str)
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(cons (cons 'Authorization
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(string-append "Basic "
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(base64-encode
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(string->utf8 str))))
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headers))
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(_ headers))))
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(unless (or buffered? (not (file-port? port)))
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(setvbuf port 'none))
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(let*-values (((resp data)
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(http-get uri #:streaming? #t #:port port
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;; XXX: When #:keep-alive? is true, if DATA is
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;; a chunked-encoding port, closing DATA won't
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;; close PORT, leading to a file descriptor
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;; leak.
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#:keep-alive? #f
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#:headers headers))
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((code)
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(response-code resp)))
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(case code
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((200)
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(values data (response-content-length resp)))
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((301 ; moved permanently
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302 ; found (redirection)
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303 ; see other
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307 ; temporary redirection
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308) ; permanent redirection
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(let ((uri (resolve-uri-reference (response-location resp) uri)))
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(close-port port)
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(format (current-error-port) (G_ "following redirection to `~a'...~%")
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(uri->string uri))
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(loop uri)))
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(else
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(raise (condition (&http-get-error
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(uri uri)
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(code code)
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(reason (response-reason-phrase resp)))
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(&message
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(message
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(format
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#f
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(G_ "~a: HTTP download failed: ~a (~s)")
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(uri->string uri) code
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(response-reason-phrase resp))))))))))))
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;;;
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;;; Caching.
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;;;
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(define %http-cache-ttl
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;; Time-to-live in seconds of the HTTP cache of in ~/.cache/guix.
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(make-parameter
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(* 3600 (or (and=> (getenv "GUIX_HTTP_CACHE_TTL")
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string->number*)
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36))))
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(define (cache-file-for-uri uri)
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"Return the name of the file in the cache corresponding to URI."
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(let ((digest (sha256 (string->utf8 (uri->string uri)))))
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;; Use the "URL" alphabet because it does not contain "/".
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(string-append (cache-directory) "/http/"
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(base64-encode digest 0 (bytevector-length digest)
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#f #f base64url-alphabet))))
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(define* (http-fetch/cached uri #:key (ttl (%http-cache-ttl)) text?
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(write-cache dump-port)
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(cache-miss (const #t)))
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"Like 'http-fetch', return an input port, but cache its contents in
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~/.cache/guix. The cache remains valid for TTL seconds.
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Call WRITE-CACHE with the HTTP input port and the cache output port to write
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the data to cache. Call CACHE-MISS with URI just before fetching data from
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URI."
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(let ((file (cache-file-for-uri uri)))
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(define (update-cache cache-port)
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(define cache-time
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(and cache-port
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(stat:mtime (stat cache-port))))
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(define headers
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`((user-agent . "GNU Guile")
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,@(if cache-time
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`((if-modified-since
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. ,(time-utc->date (make-time time-utc 0 cache-time))))
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'())))
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;; Update the cache and return an input port.
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(guard (c ((http-get-error? c)
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(if (= 304 (http-get-error-code c)) ;"Not Modified"
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(begin
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(utime file) ;update FILE's mtime
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cache-port)
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(raise c))))
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(let ((port (http-fetch uri #:text? text?
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#:headers headers)))
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(cache-miss uri)
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(mkdir-p (dirname file))
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(when cache-port
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(close-port cache-port))
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(with-atomic-file-output file
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(cut write-cache port <>))
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(close-port port)
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(open-input-file file))))
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(define (old? port)
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;; Return true if PORT has passed TTL.
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(let* ((s (stat port))
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(now (current-time time-utc)))
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(< (+ (stat:mtime s) ttl) (time-second now))))
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(catch 'system-error
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(lambda ()
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(let ((port (open-input-file file)))
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(if (old? port)
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(update-cache port)
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port)))
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(lambda args
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(if (= ENOENT (system-error-errno args))
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(update-cache #f)
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(apply throw args))))))
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;;; http-client.scm ends here
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