Fix content-length if file partly read before upload

aiohttp/client.py

@@ -9,7 +9,7 @@
 import weakref
 import warnings
 import chardet
-from os.path import getsize
+from os import fstat
 
 import aiohttp
 from . import hdrs, helpers, streams
@@ -386,7 +386,8 @@ def update_body_from_data(self, data):
             self.body = data
             if not self.chunked and isinstance(data, io.BufferedReader):
                 # Not chunking if content-length can be determined
-                self.headers[hdrs.CONTENT_LENGTH] = str(getsize(data.name))
+                size = fstat(data.fileno()).st_size - data.tell()
+                self.headers[hdrs.CONTENT_LENGTH] = str(size)
                 self.chunked = False
             else:
                 self.chunked = True

tests/test_client.py

@@ -554,6 +554,17 @@ def test_file_upload_not_chunked(self):
             self.assertEqual(req.headers['CONTENT-LENGTH'],
                              str(os.path.getsize(fname)))
 
+    def test_file_upload_not_chunked_seek(self):
+        here = os.path.dirname(__file__)
+        fname = os.path.join(here, 'sample.key')
+        with open(fname, 'rb') as f:
+            f.seek(100)
+            req = ClientRequest(
+                'post', 'http://python.org/',
+                data=f)
+            self.assertEqual(req.headers['CONTENT-LENGTH'],
+                             str(os.path.getsize(fname) - 100))
+
     def test_file_upload_force_chunked(self):
         here = os.path.dirname(__file__)
         fname = os.path.join(here, 'sample.key')