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web: Backport chunked encoding support for Guile <= 2.0.5.

* guix/web.scm (when-guile<=2.0.5): New macro.
  (read-chunk-header, read-chunk, read-chunk-body,
  make-chunked-input-port, read-response-body*)[when-guile<=2.0.5]: New
  (http-fetch): Clarify message when (not data).
Ludovic Courtès 9 years ago
  1. 110


@ -1,5 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 Ludovic Courtès <>
;;; Copyright © 2012 Free Software Foundation, Inc.
;;; This file is part of GNU Guix.
@ -17,6 +18,7 @@
;;; along with GNU Guix. If not, see <>.
(define-module (guix web)
#:use-module (guix utils)
#:use-module (web uri)
#:use-module (web client)
#:use-module (web response)
@ -33,6 +35,105 @@
;;; Code:
(define-syntax when-guile<=2.0.5
(lambda (s)
(syntax-case s ()
((_ body ...)
;; Always emit BODY, regardless of VERSION, because sometimes this code
;; might be compiled with a recent Guile and run with 2.0.5---e.g.,
;; when using "guix pull".
#'(begin body ...)))))
;; Backport of Guile commit 312e79f8 ("Add HTTP Chunked Encoding support to
;; web modules.").
(use-modules (ice-9 rdelim))
;; Chunked Responses
(define (read-chunk-header port)
(let* ((str (read-line port))
(extension-start (string-index str (lambda (c) (or (char=? c #\;)
(char=? c #\return)))))
(size (string->number (if extension-start ; unnecessary?
(substring str 0 extension-start)
(define (read-chunk port)
(let ((size (read-chunk-header port)))
(read-chunk-body port size)))
(define (read-chunk-body port size)
(let ((bv (get-bytevector-n port size)))
(get-u8 port) ; CR
(get-u8 port) ; LF
(define* (make-chunked-input-port port #:key (keep-alive? #f))
"Returns a new port which translates HTTP chunked transfer encoded
data from PORT into a non-encoded format. Returns eof when it has
read the final chunk from PORT. This does not necessarily mean
that there is no more data on PORT. When the returned port is
closed it will also close PORT, unless the KEEP-ALIVE? is true."
(define (next-chunk)
(read-chunk port))
(define finished? #f)
(define (close)
(unless keep-alive?
(close-port port)))
(define buffer #vu8())
(define buffer-size 0)
(define buffer-pointer 0)
(define (read! bv idx to-read)
(define (loop to-read num-read)
(cond ((or finished? (zero? to-read))
((<= to-read (- buffer-size buffer-pointer))
(bytevector-copy! buffer buffer-pointer
bv (+ idx num-read)
(set! buffer-pointer (+ buffer-pointer to-read))
(loop 0 (+ num-read to-read)))
(let ((n (- buffer-size buffer-pointer)))
(bytevector-copy! buffer buffer-pointer
bv (+ idx num-read)
(set! buffer (next-chunk))
(set! buffer-pointer 0)
(set! buffer-size (bytevector-length buffer))
(set! finished? (= buffer-size 0))
(loop (- to-read n)
(+ num-read n))))))
(loop to-read 0))
(make-custom-binary-input-port "chunked input port" read! #f #f close))
(define (read-response-body* r)
"Reads the response body from @var{r}, as a bytevector. Returns
@code{#f} if there was no response body."
(define bad-response
(@@ (web response) bad-response))
(if (member '(chunked) (response-transfer-encoding r))
(let ((chunk-port (make-chunked-input-port (response-port r)
#:keep-alive? #t)))
(get-bytevector-all chunk-port))
(let ((nbytes (response-content-length r)))
(and nbytes
(let ((bv (get-bytevector-n (response-port r) nbytes)))
(if (= (bytevector-length bv) nbytes)
(bad-response "EOF while reading response body: ~a bytes of ~a"
(bytevector-length bv) nbytes)))))))
;; Install this patch only on Guile 2.0.5.
(when (version>? "2.0.6" (version))
(module-set! (resolve-module '(web response))
'read-response-body read-response-body*)))
(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
@ -54,15 +155,14 @@ textual. Follow any HTTP redirection."
(let ((len (response-content-length resp)))
(cond ((not data)
;; XXX: Guile 2.0.5 and earlier did not support chunked
;; Guile 2.0.5 and earlier did not support chunked
;; transfer encoding, which is required for instance when
;; fetching %PACKAGE-LIST-URL (see
;; <>).
;; Since users may still be using these versions, warn them
;; and bail out.
(warning (_ "using Guile ~a, ~a ~s encoding~%")
;; Normally the `when-guile<=2.0.5' block above fixes
;; that, but who knows what could happen.
(warning (_ "using Guile ~a, which does not support ~s encoding~%")
"which does not support HTTP"
(response-transfer-encoding resp))
(leave (_ "download failed; use a newer Guile~%")
uri resp)))