Add LengthWrapper in put_object to honor content_length param

Closes-Bug:#1284360

Change-Id: Iec63a3fde77bb8195bfe46c764403b367999ff43

swiftclient/client.py

@@ -30,6 +30,7 @@ from urlparse import urlparse, urlunparse
 from time import sleep, time
 
 from swiftclient.exceptions import ClientException, InvalidHeadersException
+from swiftclient.utils import LengthWrapper
 
 try:
     from logging import NullHandler
@@ -935,11 +936,8 @@ def put_object(url, token=None, container=None, name=None, contents=None,
             conn.putrequest(path, headers=headers, data=chunk_reader())
         else:
             # Fixes https://github.com/kennethreitz/requests/issues/1648
-            try:
-                contents.len = content_length
-            except AttributeError:
-                pass
-            conn.putrequest(path, headers=headers, data=contents)
+            data = LengthWrapper(contents, content_length)
+            conn.putrequest(path, headers=headers, data=data)
     else:
         if chunk_size is not None:
             warn_msg = '%s object has no \"read\" method, ignoring chunk_size'\

swiftclient/utils.py

@@ -55,3 +55,21 @@ def prt_bytes(bytes, human_flag):
         bytes = '%12s' % bytes
 
     return(bytes)
+
+
+class LengthWrapper(object):
+
+    def __init__(self, readable, length):
+        self._length = self._remaining = length
+        self._readable = readable
+
+    def __len__(self):
+        return self._length
+
+    def read(self, *args, **kwargs):
+        if self._remaining <= 0:
+            return ''
+        chunk = self._readable.read(
+            *args, **kwargs)[:self._remaining]
+        self._remaining -= len(chunk)
+        return chunk

tests/test_utils.py

@@ -15,6 +15,9 @@
 
 import testtools
 
+from StringIO import StringIO
+import tempfile
+
 from swiftclient import utils as u
 
 
@@ -117,3 +120,41 @@ class TestPrtBytes(testtools.TestCase):
     def test_overflow(self):
         bytes_ = 2 ** 90
         self.assertEqual('1024Y', u.prt_bytes(bytes_, True).lstrip())
+
+
+class TestLengthWrapper(testtools.TestCase):
+
+    def test_stringio(self):
+        contents = StringIO('a' * 100)
+        data = u.LengthWrapper(contents, 42)
+        self.assertEqual(42, len(data))
+        read_data = ''.join(iter(data.read, ''))
+        self.assertEqual(42, len(read_data))
+        self.assertEqual('a' * 42, read_data)
+
+    def test_tempfile(self):
+        with tempfile.NamedTemporaryFile() as f:
+            f.write('a' * 100)
+            f.flush()
+            contents = open(f.name)
+            data = u.LengthWrapper(contents, 42)
+            self.assertEqual(42, len(data))
+            read_data = ''.join(iter(data.read, ''))
+            self.assertEqual(42, len(read_data))
+            self.assertEqual('a' * 42, read_data)
+
+    def test_segmented_file(self):
+        with tempfile.NamedTemporaryFile() as f:
+            segment_length = 1024
+            segments = ('a', 'b', 'c', 'd')
+            for c in segments:
+                f.write(c * segment_length)
+            f.flush()
+            for i, c in enumerate(segments):
+                contents = open(f.name)
+                contents.seek(i * segment_length)
+                data = u.LengthWrapper(contents, segment_length)
+                self.assertEqual(segment_length, len(data))
+                read_data = ''.join(iter(data.read, ''))
+                self.assertEqual(segment_length, len(read_data))
+                self.assertEqual(c * segment_length, read_data)