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-rw-r--r--guix/gnu-maintenance.scm4
-rw-r--r--guix/http-client.scm38
2 files changed, 30 insertions, 12 deletions
diff --git a/guix/gnu-maintenance.scm b/guix/gnu-maintenance.scm
index 62f817347f..796c2d6569 100644
--- a/guix/gnu-maintenance.scm
+++ b/guix/gnu-maintenance.scm
@@ -454,7 +454,9 @@ hosted on ftp.gnu.org, or not under that name (this is the case for
(define (string->lines str)
(string-tokenize str (char-set-complement (char-set #\newline))))
- (let ((port (http-fetch/cached %gnu-file-list-uri #:ttl (* 60 60))))
+ ;; Since https://ftp.gnu.org honors 'If-Modified-Since', the hard-coded
+ ;; TTL can be relatively short.
+ (let ((port (http-fetch/cached %gnu-file-list-uri #:ttl (* 15 60))))
(map trim-leading-components
(call-with-gzip-input-port port
(compose string->lines get-string-all))))))
diff --git a/guix/http-client.scm b/guix/http-client.scm
index 5c9342c218..853bba4fe3 100644
--- a/guix/http-client.scm
+++ b/guix/http-client.scm
@@ -306,14 +306,32 @@ Raise an '&http-get-error' condition if downloading fails."
"Like 'http-fetch', return an input port, but cache its contents in
~/.cache/guix. The cache remains valid for TTL seconds."
(let ((file (cache-file-for-uri uri)))
- (define (update-cache)
+ (define (update-cache cache-port)
+ (define cache-time
+ (and cache-port
+ (stat:mtime (stat cache-port))))
+
+ (define headers
+ `((user-agent . "GNU Guile")
+ ,@(if cache-time
+ `((if-modified-since
+ . ,(time-utc->date (make-time time-utc 0 cache-time))))
+ '())))
+
;; Update the cache and return an input port.
- (let ((port (http-fetch uri #:text? text?)))
- (mkdir-p (dirname file))
- (with-atomic-file-output file
- (cut dump-port port <>))
- (close-port port)
- (open-input-file file)))
+ (guard (c ((http-get-error? c)
+ (if (= 304 (http-get-error-code c)) ;"Not Modified"
+ cache-port
+ (raise c))))
+ (let ((port (http-fetch uri #:text? text?
+ #:headers headers)))
+ (mkdir-p (dirname file))
+ (when cache-port
+ (close-port cache-port))
+ (with-atomic-file-output file
+ (cut dump-port port <>))
+ (close-port port)
+ (open-input-file file))))
(define (old? port)
;; Return true if PORT has passed TTL.
@@ -325,13 +343,11 @@ Raise an '&http-get-error' condition if downloading fails."
(lambda ()
(let ((port (open-input-file file)))
(if (old? port)
- (begin
- (close-port port)
- (update-cache))
+ (update-cache port)
port)))
(lambda args
(if (= ENOENT (system-error-errno args))
- (update-cache)
+ (update-cache #f)
(apply throw args))))))
;;; http-client.scm ends here