Implement `parse-form-urlencoded'

2 files changed, 35 insertions, 3 deletions

diff --git a/weeb/main.scm b/weeb/main.scm
index 7487f19..b6e47ec 100644
--- a/weeb/main.scm
+++ b/weeb/main.scm
@@ -110,6 +110,11 @@
     (match-lambda
       ("GET"  'GET)
       ("POST" 'POST)))
+  (define (strip-query-string uri)
+    (let ((match-object (string-match "^(/.*)\\?" uri)))
+      (if match-object
+          (match:substring match-object 1)
+          uri)))
   ;; According to RFC 9110, header names must be treated as case-insensitive.
   (define headers
     (filter-map
@@ -125,8 +130,9 @@
              #f)))
      (environ)))
   (let* ((method (string->method (getenv "REQUEST_METHOD")))
-         (uri    (getenv "REQUEST_URI")))
-    (make-struct <request> method uri '() headers (fcgi-read))))
+         (query  (parse-form-urlencoded (getenv "QUERY_STRING")))
+         (uri    (strip-query-string (getenv "REQUEST_URI"))))
+    (make-struct <request> method uri query headers (fcgi-read))))
 
 (define (handle-errors thunk)
   (catch #t
diff --git a/weeb/request.scm b/weeb/request.scm
index 42cd933..3d18b0a 100644
--- a/weeb/request.scm
+++ b/weeb/request.scm
@@ -17,8 +17,34 @@
 ;;; License along with Weeb. If not, see <https://www.gnu.org/licenses/>.
 
 (define-module (weeb request)
+  #:use-module (ice-9 match)
   #:use-module (weeb struct)
-  #:export (<request>))
+  #:export (<request>
+            urldecode
+            parse-form-urlencoded))
 
 (define-struct <request>
   method uri parameters headers body)
+
+(define (urldecode str)
+  (let loop ((i 0) (acc ""))
+    (cond
+     ((>= i (string-length str)) acc)
+     ((char=? (string-ref str i) #\+)
+      (loop (+ i 1) (string-append acc " ")))
+     ((and (char=? (string-ref str i) #\%)
+           (<= (+ i 2) (string-length str)))
+      (let* ((hex-part (substring str (+ i 1) (+ i 3)))
+             (code (string->number hex-part 16)))
+        (if code
+            (loop (+ i 3) (string-append acc (string (integer->char code))))
+            (loop (+ i 1) (string-append acc (string (string-ref str i)))))))
+     (else
+      (loop (+ i 1) (string-append acc (string (string-ref str i))))))))
+
+(define (parse-form-urlencoded encoded)
+  (map (lambda (encoded-pair)
+         (match (map urldecode (string-split encoded-pair #\=))
+           ((key value) `(,key . ,value))))
+       (filter (lambda (x) (not (zero? (string-length x))))
+               (string-split encoded #\&))))