;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012-2018, 2020-2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2012, 2015 Free Software Foundation, Inc.
;;; Copyright © 2017 Tobias Geerinckx-Rice <me@tobias.gr>
;;;
;;; 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
;;; 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 GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix http-client)
#:use-module (web uri)
#:use-module (web http)
#:use-module ((web client) #:hide (open-socket-for-uri))
#:use-module (web request)
#:use-module (web response)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-19)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:use-module (ice-9 match)
#:use-module (ice-9 binary-ports)
#:use-module (rnrs bytevectors)
#:use-module (guix ui)
#:use-module (guix utils)
#:use-module (guix base64)
#:autoload (gcrypt hash) (sha256)
#:autoload (gnutls) (error/invalid-session error/again error/interrupted)
#:use-module ((guix build utils)
#:select (mkdir-p dump-port))
#:use-module ((guix build download)
#:select (open-socket-for-uri
(open-connection-for-uri
. guix:open-connection-for-uri)
resolve-uri-reference))
#:re-export (open-socket-for-uri)
#:export (&http-get-error
http-get-error?
http-get-error-uri
http-get-error-code
http-get-error-reason
http-get-error-headers
http-fetch
http-multiple-get
%http-cache-ttl
http-fetch/cached))
;;; Commentary:
;;;
;;; HTTP client portable among Guile versions, and with proper error condition
;;; reporting.
;;;
;;; Code:
;; HTTP GET error.
(define-condition-type &http-get-error &error
http-get-error?
(uri http-get-error-uri) ;URI
(code http-get-error-code) ;integer
(reason http-get-error-reason) ;string
(headers http-get-error-headers)) ;alist
(define* (http-fetch uri #:key port (text? #f) (buffered? #t)
(open-connection guix:open-connection-for-uri)
(keep-alive? #f)
(verify-certificate? #t)
(headers '((user-agent . "GNU Guile")))
(log-port (current-error-port))
timeout)
"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. When BUFFERED? is #f, return an
unbuffered port, suitable for use in `filtered-port'. HEADERS is an alist of
extra HTTP headers.
When KEEP-ALIVE? is true, the connection is marked as 'keep-alive' and PORT is
not closed upon completion.
When VERIFY-CERTIFICATE? is true, verify HTTPS server certificates.
TIMEOUT specifies the timeout in seconds for connection establishment; when
TIMEOUT is #f, connection establishment never times out.
Write information about redirects to LOG-PORT.
Raise an '&http-get-error' condition if downloading fails."
(define uri*
(if (string? uri) (string->uri uri) uri))
(let loop ((uri uri*)
(port (or port (open-connection uri*
#:verify-certificate?
verify-certificate?
#:timeout timeout))))
(let ((headers (match (uri-userinfo uri)
((? string? str)
(cons (cons 'Authorization
(string-append "Basic "
(base64-encode
(string->utf8 str))))
headers))
(_ headers))))
(unless (or buffered? (not (file-port? port)))
(setvbuf port 'none))
(let*-values (((resp data)
(http-get uri #:streaming? #t #:port port
#:keep-alive? keep-alive?
#:headers headers))
((code)
(response-code resp)))
(case code
((200)
(values data (response-content-length resp)))
((301 ; moved permanently
302 ; found (redirection)
303 ; see other
307 ; temporary redirection
308) ; permanent redirection
(let ((host (uri-host uri))
(uri (resolve-uri-reference (response-location resp) uri)))
(if keep-alive?
(dump-port data (%make-void-port "w0")
(response-content-length resp))
(close-port port))
(format log-port (G_ "following redirection to `~a'...~%")
(uri->string uri))
(loop uri
(or (and keep-alive?
(or (not (uri-host uri))
(string=? host (uri-host uri)))
port)
(open-connection uri
#:verify-certificate?
verify-certificate?
#:timeout timeout)))))
(else
(raise (condition (&http-get-error
(uri uri)
(code code)
(reason (response-reason-phrase resp))
(headers (response-headers resp)))
(&message
(message
(format
#f
(G_ "~a: HTTP download failed: ~a (~s)")
(uri->string uri) code
(response-reason-phrase resp))))))))))))
(define-syntax-rule (false-if-networking-error exp)
"Return #f if EXP triggers a network related exception as can occur when
reusing stale cached connections."
;; FIXME: Duplicated from 'with-cached-connection'.
(catch #t
(lambda ()
exp)
(lambda (key . args)
;; If PORT was cached and the server closed the connection in the
;; meantime, we get EPIPE. In that case, open a fresh connection and
;; retry. We might also get 'bad-response or a similar exception from
;; (web response) later on, once we've sent the request, or a
;; ERROR/INVALID-SESSION from GnuTLS.
(if (or (and (eq? key 'system-error)
(= EPIPE (system-error-errno `(,key ,@args))))
(and (eq? key 'gnutls-error)
(memq (first args)
(list error/invalid-session
;; XXX: These two are not properly handled in
;; GnuTLS < 3.7.2, in
;; 'write_to_session_record_port'; see
;; <https://bugs.gnu.org/47867>.
error/again error/interrupted)))
(memq key
'(bad-response bad-header bad-header-component)))
#f
(apply throw key args)))))
(define* (http-multiple-get base-uri proc seed requests
#:key port (verify-certificate? #t)
(open-connection guix:open-connection-for-uri)
(keep-alive? #t)
(batch-size 1000))
"Send all of REQUESTS to the server at BASE-URI. Call PROC for each
response, passing it the request object, the response, a port from which to
read the response body, and the previous result, starting with SEED, à la
'fold'. Return the final result.
When PORT is specified, use it as the initial connection on which HTTP
requests are sent; otherwise call OPEN-CONNECTION to open a new connection for
a URI. When KEEP-ALIVE? is false, close the connection port before
returning."
(let connect ((port port)
(requests requests)
(result seed))
(define batch
(if (>= batch-size (length requests))
requests
(take requests batch-size)))
;; (format (current-error-port) "connecting (~a requests left)..."
;; (length requests))
(let ((p (or port (open-connection base-uri
#:verify-certificate?
verify-certificate?))))
;; For HTTPS, P is not a file port and does not support 'setvbuf'.
(when (file-port? p)
(setvbuf p 'block (expt 2 16)))
;; Send BATCH in a row.
;; XXX: Do our own caching to work around inefficiencies when
;; communicating over TLS: <http://bugs.gnu.org/22966>.
(let-values (((buffer get) (open-bytevector-output-port)))
;; Inherit the HTTP proxying property from P.
(set-http-proxy-port?! buffer (http-proxy-port? p))
;; Swallow networking errors that could occur due to connection reuse
;; and the like; they will be handled down the road when trying to
;; read responses.
(false-if-networking-error
(begin
(for-each (cut write-request <> buffer) batch)
(put-bytevector p (get))
(force-output p))))
;; Now start processing responses.
(let loop ((sent batch)
(processed 0)
(result result))
(match sent
(()
(match (drop requests processed)
(()
(unless keep-alive?
(close-port p))
(reverse result))
(remainder
(connect p remainder result))))
((head tail ...)
(match (false-if-networking-error (read-response p))
((? response? resp)
(let* ((body (response-body-port resp))
(result (proc head resp body result)))
;; The server can choose to stop responding at any time,
;; in which case we have to try again. Check whether
;; that is the case. Note that even upon "Connection:
;; close", we can read from BODY.
(match (assq 'connection (response-headers resp))
(('connection 'close)
(close-port p)
(connect #f ;try again
(drop requests (+ 1 processed))
result))
(_
(loop tail (+ 1 processed) result)))))
(#f
(close-port p)
(connect #f ; try again
(drop requests processed)
result)))))))))
;;;
;;; Caching.
;;;
(define %http-cache-ttl
;; Time-to-live in seconds of the HTTP cache of in ~/.cache/guix.
(make-parameter
(* 3600 (or (and=> (getenv "GUIX_HTTP_CACHE_TTL")
string->number*)
36))))
(define (cache-file-for-uri uri)
"Return the name of the file in the cache corresponding to URI."
(let ((digest (sha256 (string->utf8 (uri->string uri)))))
;; Use the "URL" alphabet because it does not contain "/".
(string-append (cache-directory) "/http/"
(base64-encode digest 0 (bytevector-length digest)
#f #f base64url-alphabet))))
(define* (http-fetch/cached uri #:key (ttl (%http-cache-ttl)) text?
(headers '((user-agent . "GNU Guile")))
(write-cache dump-port)
(cache-miss (const #t))
(log-port (current-error-port))
(timeout 10))
"Like 'http-fetch', return an input port, but cache its contents in
~/.cache/guix. The cache remains valid for TTL seconds.
Call WRITE-CACHE with the HTTP input port and the cache output port to write
the data to cache. Call CACHE-MISS with URI just before fetching data from
URI.
HEADERS is an alist of extra HTTP headers, to which cache-related headers are
added automatically as appropriate.
TIMEOUT specifies the timeout in seconds for connection establishment.
Write information about redirects to LOG-PORT."
(let* ((uri (if (string? uri)
(string->uri uri)
uri))
(file (cache-file-for-uri uri)))
(define (update-cache cache-port)
(define cache-time
(and cache-port
(stat:mtime (stat cache-port))))
(define extended-headers
(if cache-time
`((if-modified-since
. ,(time-utc->date (make-time time-utc 0 cache-time)))
,@headers)
headers))
;; Update the cache and return an input port.
(guard (c ((http-get-error? c)
(if (= 304 (http-get-error-code c)) ;"Not Modified"
(begin
(utime file) ;update FILE's mtime
cache-port)
(raise c))))
(let ((port (http-fetch uri #:text? text?
#:log-port log-port
#:headers extended-headers
#:timeout timeout)))
(cache-miss uri)
(mkdir-p (dirname file))
(when cache-port
(close-port cache-port))
(with-atomic-file-output file
(cut write-cache port <>))
(close-port port)
(open-input-file file))))
(define (old? port)
;; Return true if PORT has passed TTL.
(let* ((s (stat port))
(now (current-time time-utc)))
(< (+ (stat:mtime s) ttl) (time-second now))))
(catch 'system-error
(lambda ()
(let ((port (open-input-file file)))
(if (old? port)
(update-cache port)
port)))
(lambda args
(if (= ENOENT (system-error-errno args))
(update-cache #f)
(apply throw args))))))
;;; http-client.scm ends here
