[bug#36976] [PATCH 1/1] download: Map file-name characters not allowed in store.

[Hartmut Goebel <h.goebel@crazy-compilers.com>]

In the file-name to be used for storing into the store, replace any
character not allowed in the store-file-name by an underscore.
This is only done when NAME is not given and thus defaults to
toe URL's basename. If NAME is given, this is used unchanged,
allowing for more control by other functions.

Fixes <http://issues.guix.gnu.org/issue/26175>

* guix/download.scm (safe-name): New function.
  (download-to-store): NAME defaults to the "safe" basename of URL.
---
 guix/download.scm | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/guix/download.scm b/guix/download.scm
index b24aaa0a86..249f612237 100644
--- a/guix/download.scm
+++ b/guix/download.scm
@@ -6,6 +6,7 @@
 ;;; Copyright © 2016 David Craven <david@craven.ch>
 ;;; Copyright © 2017 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2019 Guy Fleury Iteriteka <hoonandon@gmail.com>
+;;; Copyright © 2019 Hartmut Goeel <h.goebel@crazy-compilers.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -563,13 +564,27 @@ own.  This helper makes it easier to deal with \"zip bombs\"."
                       #:graft? #f
                       #:local-build? #t)))
 
-(define* (download-to-store store url #:optional (name (basename url))
+(define (safe-name name)
+  "Replace any character not allowed in a stroe name by an underscore."
+
+  (define valid-characters
+    ;; according to nix/libstore/store-api.cc
+    (string->list (string-append "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                                 "abcdefghijklmnopqrstuvwxyz"
+                                 "0123456789" "+-._?=")))
+  (string-map (lambda (c)
+                (if (member c valid-characters) c #\_))
+              name))
+
+(define* (download-to-store store url
+                            #:optional (name (safe-name (basename url)))
                             #:key (log (current-error-port)) recursive?
                             (verify-certificate? #t))
-  "Download from URL to STORE, either under NAME or URL's basename if
-omitted.  Write progress reports to LOG.  RECURSIVE? has the same effect as
-the same-named parameter of 'add-to-store'.  VERIFY-CERTIFICATE? determines
-whether or not to validate HTTPS server certificates."
+  "Download from URL to STORE, either under NAME. If NAME is omitted, URL's
+basename with invalid characters replaced is used.  Write progress reports to
+LOG.  RECURSIVE? has the same effect as the same-named parameter of
+'add-to-store'.  VERIFY-CERTIFICATE? determines whether or not to validate
+HTTPS server certificates."
   (define uri
     (string->uri url))
 
-- 
2.21.0