[bug#52555] [PATCH v3 5/8] eris/http: Add HTTP block de-referencer.

[pukkamustard <pukkamustard@posteo.net>]

* guix/eris/http.scm (eris-http-block-ref): New procedure.
---
 guix/eris/http.scm | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/guix/eris/http.scm b/guix/eris/http.scm
index a8a9520197..354d3be3be 100644
--- a/guix/eris/http.scm
+++ b/guix/eris/http.scm
@@ -18,11 +18,17 @@
 
 (define-module (guix eris http)
   #:use-module (eris utils base32)
+
   #:use-module (web uri)
+  #:use-module (web client)
+  #:use-module (web response)
 
-  #:use-module (srfi srfi-2)
+  #:use-module (rnrs base)
+  #:use-module (srfi srfi-2) ; and-let*
+  #:use-module (srfi srfi-71) ; extended let-syntax for multiple values
 
-  #:export (make-blake2b-urn-query-ref))
+  #:export (make-blake2b-urn-query-ref
+            eris-http-block-ref))
 
 (define blake2b-uri-path-regexp
   (make-regexp "^blake2b:" regexp/icase))
@@ -38,3 +44,39 @@ (define (make-blake2b-urn-query-ref block-ref)
                (blake2b-ref (base32-decode
                              (string-drop (uri-path urn) 8))))
       (block-ref blake2b-ref))))
+
+(define (make-blake2b-urn ref)
+  (string-append "urn:blake2b:" (base32-encode ref)))
+
+(define (make-request-uri host ref)
+  (build-uri (uri-scheme host)
+             #:userinfo (uri-userinfo host)
+             #:host (uri-host host)
+             #:port (uri-port host)
+             #:path "/uri-res/N2R"
+             #:query (make-blake2b-urn ref)))
+
+(define* (eris-http-block-ref
+          ref
+          #:key host
+          (open-connection (lambda (host) (open-socket-for-uri host))))
+
+  (let* ((uri (make-request-uri host ref))
+         (_ (format #t "URI: ~a\n" uri))
+         (response body
+                   (http-get uri
+                             #:decode-body? #f
+                             #:port (open-connection host)
+                             #:keep-alive? #t)))
+    (if (eqv? (response-code response) 200)
+        body
+        #f)))
+
+;; (use-modules (eris)
+;;              (rnrs bytevectors))
+
+;; (bytevector?
+;;  (eris-http-block-ref
+;;   (base32-decode
+;;    "4ACQM2Q5IB3DBHGKHM2WRTAXDBPMVZ7F6MG2TUXZ5QOJHW7P4N7Q")
+;;   #:host (string->uri "http://localhost:8081")))
-- 
2.38.1