From deb46fef31faa29fc24ca1488fbd2efb22ebd380 Mon Sep 17 00:00:00 2001
From: Dmitriy Ryajov <dryajov@gmail.com>
Date: Fri, 11 Jun 2021 20:14:53 -0600
Subject: [PATCH] fix messages with multiple empty frames (#61)

---
 ws/session.nim | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/ws/session.nim b/ws/session.nim
index 10fb620..904ab2d 100644
--- a/ws/session.nim
+++ b/ws/session.nim
@@ -354,28 +354,26 @@ proc recv*(
         trace "Setting binary flag"
 
       let len = min(ws.frame.remainder.int, size - consumed)
-      if len <= 0:
-        trace "Nothing left to read, breaking!"
-        break
+      if len > 0:
+        trace "Reading bytes from frame stream", len
+        let read = await ws.stream.reader.readOnce(addr pbuffer[consumed], len)
+        if read <= 0:
+          trace "Didn't read any bytes, breaking"
+          break
 
-      trace "Reading bytes from frame stream", len
-      let read = await ws.stream.reader.readOnce(addr pbuffer[consumed], len)
-      if read <= 0:
-        trace "Didn't read any bytes, breaking"
-        break
+        trace "Read data from frame", read
 
-      if ws.frame.mask:
-        trace "Unmasking frame"
-        # unmask data using offset
-        mask(
-          pbuffer.toOpenArray(consumed, (consumed + read) - 1),
-          ws.frame.maskKey,
-          ws.frame.consumed.int)
+        if ws.frame.mask:
+          trace "Unmasking frame"
+          # unmask data using offset
+          mask(
+            pbuffer.toOpenArray(consumed, (consumed + read) - 1),
+            ws.frame.maskKey,
+            ws.frame.consumed.int)
 
-      consumed += read
-      ws.frame.consumed += read.uint64
+        consumed += read
+        ws.frame.consumed += read.uint64
 
-      trace "Read data from frame", read
       # all has been consumed from the frame
       # read the next frame
       if ws.frame.remainder <= 0: