Fixes #27

Preserve size in chunk buffer until CRLF is received avoiding error in
cases when received data contains size without a following CRLF.

proxy.py

@@ -79,17 +79,27 @@ class ChunkParser(object):
 
     def __init__(self):
         self.state = CHUNK_PARSER_STATE_WAITING_FOR_SIZE
-        self.body = b''
-        self.chunk = b''
-        self.size = None
+        self.body = b''     # Parsed chunks
+        self.chunk = b''    # Partial chunk received
+        self.size = None    # Expected size of next following chunk
 
     def parse(self, data):
         more = True if len(data) > 0 else False
-        while more: more, data = self.process(data)
+        while more:
+            more, data = self.process(data)
 
     def process(self, data):
         if self.state == CHUNK_PARSER_STATE_WAITING_FOR_SIZE:
+            # Consume prior chunk in buffer
+            # in case chunk size without CRLF was received
+            data = self.chunk + data
+            self.chunk = b''
+            # Extract following chunk data size
             line, data = HttpParser.split(data)
+            if not line:    # CRLF not received
+                self.chunk = data
+                data = b''
+            else:
                 self.size = int(line, 16)
                 self.state = CHUNK_PARSER_STATE_WAITING_FOR_DATA
         elif self.state == CHUNK_PARSER_STATE_WAITING_FOR_DATA:
@@ -388,8 +398,7 @@ class Proxy(threading.Thread):
             elif self.request.url:
                 host, port = self.request.url.hostname, self.request.url.port if self.request.url.port else 80
             else:
-                # TODO(abhinavsingh): Gracefully return invalid request in such cases
-                pass
+                raise Exception('Invalid request\n%s' % self.request.raw)
 
             self.server = Server(host, port)
             try:

tests.py

@@ -24,6 +24,43 @@ class TestChunkParser(unittest.TestCase):
         self.assertEqual(self.parser.body, b'Wikipedia in\r\n\r\nchunks.')
         self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_COMPLETE)
 
+    def test_chunk_parse_issue_27(self):
+        self.parser.parse(b'3')
+        self.assertEqual(self.parser.chunk, b'3')
+        self.assertEqual(self.parser.size, None)
+        self.assertEqual(self.parser.body, b'')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_WAITING_FOR_SIZE)
+        self.parser.parse(b'\r\n')
+        self.assertEqual(self.parser.chunk, b'')
+        self.assertEqual(self.parser.size, 3)
+        self.assertEqual(self.parser.body, b'')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_WAITING_FOR_DATA)
+        self.parser.parse(b'abc')
+        self.assertEqual(self.parser.chunk, b'')
+        self.assertEqual(self.parser.size, None)
+        self.assertEqual(self.parser.body, b'abc')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_WAITING_FOR_SIZE)
+        self.parser.parse(b'\r\n')
+        self.assertEqual(self.parser.chunk, b'')
+        self.assertEqual(self.parser.size, None)
+        self.assertEqual(self.parser.body, b'abc')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_WAITING_FOR_SIZE)
+        self.parser.parse(b'4\r\n')
+        self.assertEqual(self.parser.chunk, b'')
+        self.assertEqual(self.parser.size, 4)
+        self.assertEqual(self.parser.body, b'abc')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_WAITING_FOR_DATA)
+        self.parser.parse(b'defg\r\n0')
+        self.assertEqual(self.parser.chunk, b'0')
+        self.assertEqual(self.parser.size, None)
+        self.assertEqual(self.parser.body, b'abcdefg')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_WAITING_FOR_SIZE)
+        self.parser.parse(b'\r\n\r\n')
+        self.assertEqual(self.parser.chunk, b'')
+        self.assertEqual(self.parser.size, None)
+        self.assertEqual(self.parser.body, b'abcdefg')
+        self.assertEqual(self.parser.state, CHUNK_PARSER_STATE_COMPLETE)
+
 
 class TestHttpParser(unittest.TestCase):