Make body_iter async generator compatible with MicroPython

src/microdot_asgi.py

@@ -88,7 +88,7 @@ class Microdot(BaseMicrodot):
                     'status': res.status_code,
                     'headers': [(name, value)
                                 for name, value in res.headers.items()]})
-        body_iter = res.body_iter()
+        body_iter = res.body_iter().__aiter__()
         body = b''
         try:
             body += await body_iter.__anext__()

src/microdot_asyncio.py

@@ -136,24 +136,38 @@ class Response(BaseResponse):
         async for body in self.body_iter():
             await stream.awrite(body)
 
-    async def body_iter(self):
-        if self.body:
-            if hasattr(self.body, 'read'):
-                while True:
-                    buf = self.body.read(self.send_file_buffer_size)
-                    if _iscoroutine(buf):  # pragma: no cover
-                        buf = await buf
-                    if len(buf):
-                        print('*', buf, self.send_file_buffer_size)
-                        yield buf
-                    if len(buf) < self.send_file_buffer_size:
-                        break
-                if hasattr(self.body, 'close'):  # pragma: no cover
-                    result = self.body.close()
-                    if _iscoroutine(result):
-                        await result
-            else:
-                yield self.body
+    def body_iter(self):
+        response = self
+
+        class iter:
+            def __aiter__(self):
+                if response.body:
+                    self.i = 0
+                else:
+                    self.i = -1
+                return self
+
+            async def __anext__(self):
+                if self.i == -1:
+                    raise StopAsyncIteration
+                if self.i == 0:
+                    if not hasattr(response.body, 'read'):
+                        self.i = -1
+                        return response.body
+                    else:
+                        self.i = 1
+                buf = response.body.read(response.send_file_buffer_size)
+                if _iscoroutine(buf):  # pragma: no cover
+                    buf = await buf
+                if len(buf) < response.send_file_buffer_size:
+                    self.i = -1
+                    if hasattr(response.body, 'close'):  # pragma: no cover
+                        result = response.body.close()
+                        if _iscoroutine(result):
+                            await result
+                return buf
+
+        return iter()
 
 
 class Microdot(BaseMicrodot):

tests/microdot_asgi/test_microdot_asgi.py

@@ -65,7 +65,8 @@ class TestMicrodotASGI(unittest.TestCase):
                     packet['headers'],
                     [('Content-Length', '8'), ('Content-Type', 'text/plain')])
             elif packet['type'] == 'http.response.body':
-                self.assertIn(packet['body'], [b're', b'sp', b'on', b'se'])
+                self.assertIn(packet['body'],
+                              [b're', b'sp', b'on', b'se', b''])
 
         original_buffer_size = Response.send_file_buffer_size
         Response.send_file_buffer_size = 2