Don't save unmodified code

_web_server/server/playground-server.scm

@@ -809,6 +809,15 @@
                    (uri-path
                     (request-uri request))))
 
+            ;; Snippet dir path relative to stor-base
+            (ref-stor-dir
+             (let ((ref (assoc 'referer (request-headers request))))
+               (and ref
+                    (let ((p (get-storage-dir (cdr ref) root)))
+                      (and (storage-dir-valid? p)
+                           (storage-path-exists? (path+ stor-base p))
+                           p)))))
+
             ;; Body of the POST request
             (code
              (if request-body
@@ -828,6 +837,10 @@
 
         (logger LOG-VERBOSE "Request ~a:~a" (request-method request) path)
         (logger LOG-VERBOSE "Request query:~a" query)
+        (logger LOG-DBG "  stor:'~a' len:~a/~a"
+                ref-stor-dir
+                (request-content-length request)
+                (string-length code))
 
         (cond
          ;;
@@ -909,6 +922,17 @@
            ;; Save snippet
            ((or (equal? path savecode-path))
             (logger LOG-DBG "Request code saving")
+            (let ((old-code
+                   (if ref-stor-dir
+                       (read-from-storage (path+ stor-base ref-stor-dir))
+                       DEFAULT-CODE)))
+              (if (equal? code old-code)
+                  ;; If code is not changed do nothing
+                  (make-response
+                   (encode-and-join-uri-path
+                    (append root-path `(,ref-stor-dir)))
+                   #:content-type 'text/plain)
+                  ;; New code save to new location
                   (let ((stor-dir
                          (basename
                           (mkdtemp
@@ -921,7 +945,7 @@
                     (make-response
                      (encode-and-join-uri-path
                       (append root-path `(,stor-dir)))
-               #:content-type 'text/plain)))
+                     #:content-type 'text/plain)))))
 
            ;; Wrong POST request
            (else