bug#69381: [PATCH] Convert HTML to UTF-8 ourselves. (Closes: #69381)

[Felix Lechner via Bug-mumi via "Bug reports for GNU Guix Mumi." <bug-mumi@gnu.org>]

This fixes a host of encoding issues in Mumi, including the diff
problems that are not mentioned in the bug.  An example is here:

    https://issues.guix.gnu.org/63508#4

The procedure version may one day be more efficient but does not work.
Based on comments in the Guile source code, the procedure style may
one day enable more advanced response formats.  The author is unclear
as to why the procedure does not work.  There may be a complex
interaction involving the response headers.

A preview of this code is live at patchwise.org.

The solution of this bug may depend on the patch in Bug#70907.  This
patch furthermore depends on the patch in Bug#70906, but the solution
of the bug may not.
---
 mumi/web/render.scm | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mumi/web/render.scm b/mumi/web/render.scm
index 316ca4c..9b16f8d 100644
--- a/mumi/web/render.scm
+++ b/mumi/web/render.scm
@@ -28,6 +28,7 @@
   #:use-module ((ice-9 textual-ports)
                 #:select (get-string-all put-string))
   #:use-module (ice-9 match)
+  #:use-module (rnrs bytevectors)
   #:use-module (web http)
   #:use-module (web request)
   #:use-module (web response)
@@ -104,13 +105,13 @@
 (define* (render-html sxml #:key (extra-headers '()))
   (values (append extra-headers
                   '((content-type . (text/html (charset . "utf-8")))))
-          (lambda (port)
-            (sxml->html sxml port))))
+          (string->utf8
+           (sxml->html-string sxml))))
 
 (define (render-json json)
   (values '((content-type . (application/json (charset . "utf-8"))))
-          (lambda (port)
-            (scm->json json port))))
+          (string->utf8
+           (scm->json-string json))))
 
 (define (not-found uri)
   (values (build-response #:code 404)
-- 
2.41.0