Respect "content-length" header

stomp.el

@@ -42,13 +42,19 @@
    be deleted from the buffer."
   (let ((frame (stomp-read-frame buffer)))
     (cond
-     (frame (stomp-delete-frame buffer) frame)
+     (frame (stomp-delete-frame buffer frame) frame)
      (t nil))))
 
-(defun stomp-delete-frame (buffer)
+(defun stomp-delete-frame (buffer frame)
   "Delete the top-most messsage in a buffer"
   (with-current-buffer buffer
-    (delete-region (point-min) (+ 2 (stomp-find-frame-end-point buffer)))))
+    (delete-region (point-min) (+ 2 (stomp-find-frame-end-point buffer frame)))))
+
+(defun stomp-frame-header (header frame)
+  "Shortcut to access frame headers"
+  (assoc-default
+   "content-length"
+   (alist-get 'headers frame nil) 'string-equal nil))
 
 (defun stomp-read-frame (buffer)
   "Attempt to read a single frame from a buffer.
@@ -57,16 +63,16 @@
    frames in the buffer, nil will be returned."
   (with-current-buffer buffer
     (let ((frame ())
-          (headers-end-point (stomp-find-headers-end-point buffer))
-          (frame-end-point (stomp-find-frame-end-point buffer)))
+          (headers-end-point (stomp-find-headers-end-point buffer)))
       (goto-char (point-min))
       (cond
-       ((and frame-end-point headers-end-point)
+       ((and headers-end-point)
         (map-put frame 'command (current-word))
         (map-put frame 'headers (stomp-read-headers buffer headers-end-point))
-        ;; TODO: take content-length header into account
-        ;; This is might be hard to do if the content contains carriage returns.
-        (map-put frame 'content (buffer-substring (+ 1 headers-end-point) frame-end-point)))
+        (map-put frame 'content
+                 (buffer-substring
+                  (+ 1 headers-end-point)
+                  (stomp-find-frame-end-point buffer frame headers-end-point))))
        (t nil)))))
 
 (defun stomp-read-headers (buffer end-point &optional headers)
@@ -78,17 +84,28 @@
       (cond
        ((= (line-end-position) end-point) headers)
        ((> (length header) 2) (throw 'invalid-header nil))
-       (t (stomp-read-headers buffer end-point
-                              (map-put headers
-                                       (car header)
-                                       (replace-regexp-in-string "\\(\n\\|\r\n\\)$" "" (car (last header))))))))))
+       (t (stomp-read-headers
+           buffer
+           end-point
+           (map-put headers
+                    (car header)
+                    (replace-regexp-in-string "\\(\n\\|\r\n\\)$" "" (car (last header))))))))))
 
-(defun stomp-find-frame-end-point (buffer)
-  "Find the null byte at the end of a STOMP frame"
+(defun stomp-find-frame-end-point (buffer frame &optional headers-end-point)
+  "Find the end point of a STOMP frame at the top of a buffer,
+   either by using the content-length header or by searching for
+   the null octet."
   (with-current-buffer buffer
-    (goto-char (point-min))
-    (search-forward-regexp "\u0000\\|\u0000\r")
-    (- (point) 1)))
+    (let ((content-length (stomp-frame-header "content-length" frame))
+          (headers-end-point(if headers-end-point
+                                 headers-end-point
+                               (stomp-find-headers-end-point buffer))))
+      (if content-length
+          (+ headers-end-point 1 (string-to-number content-length))
+        (progn
+          (goto-char (point-min))
+          (search-forward-regexp "\u0000\\|\u0000\r")
+          (- (point) 1))))))
 
 (defun stomp-find-headers-end-point (buffer)
   "Find the end of the header part of a STOMP frame."

test/test.el

@@ -48,12 +48,24 @@
                     ("some-header" . "value"))))
    (should (equal (alist-get 'content recieved) "content\r\n"))))
 
+(ert-deftest can-read-fixed-length-frame ()
+  "Can read a frame that has a content-length header correctly"
+  (with-testing-buffer
+   "content_length_frame.txt"
+   (setq recieved (stomp-read-frame (current-buffer)))
+
+   (should (equal (alist-get 'command recieved) "MESSAGE"))
+   (should (equal (alist-get 'headers recieved)
+                  '(("destination" . "/banana/kiwi")
+                    ("content-length" . "11"))))
+   (should (equal (alist-get 'content recieved) "jwe\u0000jsiwli\u0000"))))
+
 (ert-deftest can-delete-one-frame ()
   "Can delete the topmost frame in a buffer"
   (with-testing-buffer
    "multiple_frames.txt"
    (let ((buffer (current-buffer)))
-     (stomp-delete-frame buffer)
+     (stomp-delete-frame buffer nil)
      (with-current-buffer buffer
        (should (equal (buffer-string) "BLA\nsome-header:value\nok:bye\n\ncontent\n\u0000\n"))))))