refactor code to better handle premature disconnects

uvscand/__init__.py

@@ -38,6 +38,7 @@ async def uvscan_worker(queue):
         uvscan, filename, cb = job
         proc = await asyncio.create_subprocess_exec(uvscan, "--secure", "--mime", "--noboot", "--panalyse", "--manalyse", filename, stdout=asyncio.subprocess.PIPE)
         stdout, _ = await proc.communicate()
+        os.remove(filename)
         if proc.returncode == 13:
             match = uvscan_regex.search(stdout.decode())
             name = match.group(1) if match else "UNKNOWN"
@@ -136,38 +137,37 @@ class AIO(asyncio.Protocol):
             self._send_response(str(e))
 
     def process_uvscan_result(self, result):
-        self.logger.debug(f"{self.peer} removing temporary file {self.tmpfile}")
-        os.remove(self.tmpfile)
+        if not self.tmpfile:
+            return
+
+        self.logger.info(f"{self.peer} received uvscan result of {self.tmpfile}: {result}")
+        self._send_response(result)
         self.tmpfile = None
-        if not self.cancelled:
-            self.logger.info(f"{self.peer} received uvscan result of {self.tmpfile}: {result}")
-            self._send_response(result)
 
     def connection_lost(self, exc):
-        if self.tmpfile:
-            entries = []
-            try:
-                for entry in iter(AIO.queue.get_nowait, None):
-                    if not entry:
-                        continue
-                    if entry[1] != self.tmpfile:
-                        entries.append(entry)
-                    else:
-                        self.cancelled = True
-            except asyncio.QueueEmpty:
-                pass
-            for entry in entries:
-                AIO.queue.put_nowait(entry)
-            if self.cancelled:
-                self.logger.warning(f"{self.peer} client prematurely closed connection, skipped scan of {self.tmpfile}")
-                self.logger.debug(f"{self.peer} removing temporary file {self.tmpfile}")
-                os.remove(self.tmpfile)
-            else:
-                self.logger.warning(f"{self.peer} client prematurely closed connection")
-                self.cancelled = True
-
-        else:
+        if not self.tmpfile:
             self.logger.info(f"closed connection to {self.peer}")
+            return
+
+        entries = []
+        try:
+            for entry in iter(AIO.queue.get_nowait, None):
+                if not entry:
+                    continue
+                if self.tmpfile and entry[1] == self.tmpfile:
+                    self.logger.warning(f"{self.peer} client prematurely closed connection, skipping scan of {self.tmpfile}")
+                    os.remove(self.tmpfile)
+                    self.tmpfile = None
+                    continue
+                entries.append(entry)
+        except asyncio.QueueEmpty:
+            pass
+        for entry in entries:
+            AIO.queue.put_nowait(entry)
+
+        if self.tmpfile:
+            self.logger.warning(f"{self.peer} client prematurely closed connection, but scan is already running")
+            self.tmpfile = None
 
 
 def main():