Merge "Support multi-range GETs for static large objects."

swift/common/middleware/slo.py

@@ -213,12 +213,11 @@ from swift.common.exceptions import ListingIterError, SegmentError
 from swift.common.swob import Request, HTTPBadRequest, HTTPServerError, \
     HTTPMethodNotAllowed, HTTPRequestEntityTooLarge, HTTPLengthRequired, \
     HTTPOk, HTTPPreconditionFailed, HTTPException, HTTPNotFound, \
-    HTTPUnauthorized, HTTPConflict, HTTPRequestedRangeNotSatisfiable,\
-    Response, Range
+    HTTPUnauthorized, HTTPConflict, Response, Range
 from swift.common.utils import get_logger, config_true_value, \
     get_valid_utf8_str, override_bytes_from_content_type, split_path, \
     register_swift_info, RateLimitedIterator, quote, close_if_possible, \
-    closing_if_possible
+    closing_if_possible, LRUCache
 from swift.common.request_helpers import SegmentedIterable
 from swift.common.constraints import check_utf8, MAX_BUFFERED_SLO_SEGMENTS
 from swift.common.http import HTTP_NOT_FOUND, HTTP_UNAUTHORIZED, is_success
@@ -386,8 +385,6 @@ class SloGetContext(WSGIContext):
 
     def __init__(self, slo):
         self.slo = slo
-        self.first_byte = None
-        self.last_byte = None
         super(SloGetContext, self).__init__(slo.app)
 
     def _fetch_sub_slo_segments(self, req, version, acc, con, obj):
@@ -434,7 +431,7 @@ class SloGetContext(WSGIContext):
             return int(seg_dict['bytes'])
 
     def _segment_listing_iterator(self, req, version, account, segments,
-                                  recursion_depth=1):
+                                  byteranges):
         for seg_dict in segments:
             if config_true_value(seg_dict.get('sub_slo')):
                 override_bytes_from_content_type(seg_dict,
@@ -448,23 +445,46 @@ class SloGetContext(WSGIContext):
         # If we were to make SegmentedIterable handle all the range
         # calculations, we would be unable to make this optimization.
         total_length = sum(self._segment_length(seg) for seg in segments)
-        if self.first_byte is None:
-            self.first_byte = 0
-        if self.last_byte is None:
-            self.last_byte = total_length - 1
+        if not byteranges:
+            byteranges = [(0, total_length - 1)]
 
+        # Cache segments from sub-SLOs in case more than one byterange
+        # includes data from a particular sub-SLO. We only cache a few sets
+        # of segments so that a malicious user cannot build a giant SLO tree
+        # and then GET it to run the proxy out of memory.
+        #
+        # LRUCache is a little awkward to use this way, but it beats doing
+        # things manually.
+        #
+        # 20 is sort of an arbitrary choice; it's twice our max recursion
+        # depth, so we know this won't expand memory requirements by too
+        # much.
+        cached_fetch_sub_slo_segments = \
+            LRUCache(maxsize=20)(self._fetch_sub_slo_segments)
+
+        for first_byte, last_byte in byteranges:
+            byterange_listing_iter = self._byterange_listing_iterator(
+                req, version, account, segments, first_byte, last_byte,
+                cached_fetch_sub_slo_segments)
+            for seg_info in byterange_listing_iter:
+                yield seg_info
+
+    def _byterange_listing_iterator(self, req, version, account, segments,
+                                    first_byte, last_byte,
+                                    cached_fetch_sub_slo_segments,
+                                    recursion_depth=1):
         last_sub_path = None
         for seg_dict in segments:
             seg_length = self._segment_length(seg_dict)
-            if self.first_byte >= seg_length:
+            if first_byte >= seg_length:
                 # don't need any bytes from this segment
-                self.first_byte -= seg_length
-                self.last_byte -= seg_length
+                first_byte -= seg_length
+                last_byte -= seg_length
                 continue
 
-            if self.last_byte < 0:
+            if last_byte < 0:
                 # no bytes are needed from this or any future segment
-                break
+                return
 
             seg_range = seg_dict.get('range')
             if seg_range is None:
@@ -483,33 +503,30 @@ class SloGetContext(WSGIContext):
                 sub_path = get_valid_utf8_str(seg_dict['name'])
                 sub_cont, sub_obj = split_path(sub_path, 2, 2, True)
                 if last_sub_path != sub_path:
-                    sub_segments = self._fetch_sub_slo_segments(
+                    sub_segments = cached_fetch_sub_slo_segments(
                         req, version, account, sub_cont, sub_obj)
                 last_sub_path = sub_path
 
                 # Use the existing machinery to slice into the sub-SLO.
-                # This requires that we save off our current state, and
-                # restore at the other end.
-                orig_start, orig_end = self.first_byte, self.last_byte
-                self.first_byte = range_start + max(0, self.first_byte)
-                self.last_byte = min(range_end, range_start + self.last_byte)
-
-                for sub_seg_dict, sb, eb in self._segment_listing_iterator(
+                for sub_seg_dict, sb, eb in self._byterange_listing_iterator(
                         req, version, account, sub_segments,
+                        # This adjusts first_byte and last_byte to be
+                        # relative to the sub-SLO.
+                        range_start + max(0, first_byte),
+                        min(range_end, range_start + last_byte),
+
+                        cached_fetch_sub_slo_segments,
                         recursion_depth=recursion_depth + 1):
                     yield sub_seg_dict, sb, eb
-
-                # Restore the first/last state
-                self.first_byte, self.last_byte = orig_start, orig_end
             else:
                 if isinstance(seg_dict['name'], six.text_type):
                     seg_dict['name'] = seg_dict['name'].encode("utf-8")
                 yield (seg_dict,
-                       max(0, self.first_byte) + range_start,
-                       min(range_end, range_start + self.last_byte))
+                       max(0, first_byte) + range_start,
+                       min(range_end, range_start + last_byte))
 
-            self.first_byte -= seg_length
-            self.last_byte -= seg_length
+            first_byte -= seg_length
+            last_byte -= seg_length
 
     def _need_to_refetch_manifest(self, req):
         """
@@ -692,22 +709,18 @@ class SloGetContext(WSGIContext):
 
     def _manifest_get_response(self, req, content_length, response_headers,
                                segments):
-        self.first_byte, self.last_byte = None, None
         if req.range:
-            byteranges = req.range.ranges_for_length(content_length)
-            if len(byteranges) == 0:
-                return HTTPRequestedRangeNotSatisfiable(request=req)
-            elif len(byteranges) == 1:
-                self.first_byte, self.last_byte = byteranges[0]
+            byteranges = [
                 # For some reason, swob.Range.ranges_for_length adds 1 to the
                 # last byte's position.
-                self.last_byte -= 1
+                (start, end - 1) for start, end
+                in req.range.ranges_for_length(content_length)]
         else:
-                req.range = None
+            byteranges = []
 
         ver, account, _junk = req.split_path(3, 3, rest_with_last=True)
         plain_listing_iter = self._segment_listing_iterator(
-            req, ver, account, segments)
+            req, ver, account, segments, byteranges)
 
         def is_small_segment((seg_dict, start_byte, end_byte)):
             start = 0 if start_byte is None else start_byte

swift/common/request_helpers.py

@@ -35,11 +35,11 @@ from swift.common.constraints import FORMAT2CONTENT_TYPE
 from swift.common.exceptions import ListingIterError, SegmentError
 from swift.common.http import is_success
 from swift.common.swob import HTTPBadRequest, HTTPNotAcceptable, \
-    HTTPServiceUnavailable, Range, is_chunked
+    HTTPServiceUnavailable, Range, is_chunked, multi_range_iterator
 from swift.common.utils import split_path, validate_device_partition, \
     close_if_possible, maybe_multipart_byteranges_to_document_iters, \
     multipart_byteranges_to_document_iters, parse_content_type, \
-    parse_content_range, csv_append, list_from_csv
+    parse_content_range, csv_append, list_from_csv, Spliterator
 
 from swift.common.wsgi import make_subrequest
 
@@ -520,6 +520,25 @@ class SegmentedIterable(object):
         """
         return self
 
+    def app_iter_ranges(self, ranges, content_type, boundary, content_size):
+        """
+        This method assumes that iter(self) yields all the data bytes that
+        go into the response, but none of the MIME stuff. For example, if
+        the response will contain three MIME docs with data "abcd", "efgh",
+        and "ijkl", then iter(self) will give out the bytes "abcdefghijkl".
+
+        This method inserts the MIME stuff around the data bytes.
+        """
+        si = Spliterator(self)
+        mri = multi_range_iterator(
+            ranges, content_type, boundary, content_size,
+            lambda start, end_plus_one: si.take(end_plus_one - start))
+        try:
+            for x in mri:
+                yield x
+        finally:
+            self.close()
+
     def validate_first_segment(self):
         """
         Start fetching object data to ensure that the first segment (if any) is

swift/common/swob.py

@@ -1247,9 +1247,9 @@ class Response(object):
             ranges = self.request.range.ranges_for_length(self.content_length)
             if ranges == []:
                 self.status = 416
-                self.content_length = 0
                 close_if_possible(app_iter)
-                return ['']
+                body = None
+                app_iter = None
             elif ranges:
                 range_size = len(ranges)
                 if range_size > 0:

swift/common/utils.py

@@ -3401,6 +3401,80 @@ class LRUCache(object):
         return LRUCacheWrapped()
 
 
+class Spliterator(object):
+    """
+    Takes an iterator yielding sliceable things (e.g. strings or lists) and
+    yields subiterators, each yielding up to the requested number of items
+    from the source.
+
+    >>> si = Spliterator(["abcde", "fg", "hijkl"])
+    >>> ''.join(si.take(4))
+    "abcd"
+    >>> ''.join(si.take(3))
+    "efg"
+    >>> ''.join(si.take(1))
+    "h"
+    >>> ''.join(si.take(3))
+    "ijk"
+    >>> ''.join(si.take(3))
+    "l"  # shorter than requested; this can happen with the last iterator
+
+    """
+    def __init__(self, source_iterable):
+        self.input_iterator = iter(source_iterable)
+        self.leftovers = None
+        self.leftovers_index = 0
+        self._iterator_in_progress = False
+
+    def take(self, n):
+        if self._iterator_in_progress:
+            raise ValueError("cannot call take() again until the first"
+                             " iterator is exhausted")
+        self._iterator_in_progress = True
+
+        try:
+            if self.leftovers:
+                # All this string slicing is a little awkward, but it's for
+                # a good reason. Consider a length N string that someone is
+                # taking k bytes at a time.
+                #
+                # With this implementation, we create one new string of
+                # length k (copying the bytes) on each call to take(). Once
+                # the whole input has been consumed, each byte has been
+                # copied exactly once, giving O(N) bytes copied.
+                #
+                # If, instead of this, we were to set leftovers =
+                # leftovers[k:] and omit leftovers_index, then each call to
+                # take() would copy k bytes to create the desired substring,
+                # then copy all the remaining bytes to reset leftovers,
+                # resulting in an overall O(N^2) bytes copied.
+                llen = len(self.leftovers) - self.leftovers_index
+                if llen <= n:
+                    n -= llen
+                    yield self.leftovers[self.leftovers_index:]
+                    self.leftovers = None
+                    self.leftovers_index = 0
+                else:
+                    yield self.leftovers[
+                        self.leftovers_index:(self.leftovers_index + n)]
+                    self.leftovers_index += n
+                    n = 0
+
+            while n > 0:
+                chunk = next(self.input_iterator)
+                cl = len(chunk)
+                if cl <= n:
+                    n -= cl
+                    yield chunk
+                else:
+                    yield chunk[:n]
+                    self.leftovers = chunk
+                    self.leftovers_index = n
+                    n = 0
+        finally:
+            self._iterator_in_progress = False
+
+
 def tpool_reraise(func, *args, **kwargs):
     """
     Hack to work around Eventlet's tpool not catching and reraising Timeouts.

test/functional/tests.py

@@ -3349,6 +3349,34 @@ class TestSlo(Base):
         self.assertEqual('b', file_contents[-2])
         self.assertEqual('c', file_contents[-1])
 
+    def test_slo_multi_ranged_get(self):
+        file_item = self.env.container.file('manifest-abcde')
+        file_contents = file_item.read(
+            hdrs={"Range": "bytes=1048571-1048580,2097147-2097156"})
+
+        # See testMultiRangeGets for explanation
+        parser = email.parser.FeedParser()
+        parser.feed("Content-Type: %s\r\n\r\n" % file_item.content_type)
+        parser.feed(file_contents)
+
+        root_message = parser.close()
+        self.assertTrue(root_message.is_multipart())  # sanity check
+
+        byteranges = root_message.get_payload()
+        self.assertEqual(len(byteranges), 2)
+
+        self.assertEqual(byteranges[0]['Content-Type'],
+                         "application/octet-stream")
+        self.assertEqual(
+            byteranges[0]['Content-Range'], "bytes 1048571-1048580/4194305")
+        self.assertEqual(byteranges[0].get_payload(), "aaaaabbbbb")
+
+        self.assertEqual(byteranges[1]['Content-Type'],
+                         "application/octet-stream")
+        self.assertEqual(
+            byteranges[1]['Content-Range'], "bytes 2097147-2097156/4194305")
+        self.assertEqual(byteranges[1].get_payload(), "bbbbbccccc")
+
     def test_slo_ranged_submanifest(self):
         file_item = self.env.container.file('manifest-abcde-submanifest')
         file_contents = file_item.read(size=1024 * 1024 + 2,

test/unit/common/middleware/test_slo.py

@@ -22,12 +22,14 @@ import time
 import unittest
 from mock import patch
 from hashlib import md5
+from StringIO import StringIO
 from swift.common import swob, utils
 from swift.common.exceptions import ListingIterError, SegmentError
 from swift.common.header_key_dict import HeaderKeyDict
 from swift.common.middleware import slo
 from swift.common.swob import Request, HTTPException
-from swift.common.utils import quote, closing_if_possible, close_if_possible
+from swift.common.utils import quote, closing_if_possible, close_if_possible, \
+    parse_content_type, iter_multipart_mime_documents, parse_mime_headers
 from test.unit.common.middleware.helpers import FakeSwift
 
 
@@ -1754,6 +1756,116 @@ class TestSloGetManifest(SloTestCase):
         self.assertEqual(self.app.swift_sources[1:],
                          ['SLO'] * (len(self.app.swift_sources) - 1))
 
+    def test_multiple_ranges_get_manifest(self):
+        req = Request.blank(
+            '/v1/AUTH_test/gettest/manifest-abcd',
+            environ={'REQUEST_METHOD': 'GET'},
+            headers={'Range': 'bytes=3-17,20-24,35-999999'})
+        status, headers, body = self.call_slo(req)
+        headers = HeaderKeyDict(headers)
+
+        self.assertEqual(status, '206 Partial Content')
+
+        ct, params = parse_content_type(headers['Content-Type'])
+        params = dict(params)
+        self.assertEqual(ct, 'multipart/byteranges')
+        boundary = params.get('boundary')
+        self.assertTrue(boundary is not None)
+
+        self.assertEqual(len(body), int(headers['Content-Length']))
+
+        got_mime_docs = []
+        for mime_doc_fh in iter_multipart_mime_documents(
+                StringIO(body), boundary):
+            headers = parse_mime_headers(mime_doc_fh)
+            body = mime_doc_fh.read()
+            got_mime_docs.append((headers, body))
+        self.assertEqual(len(got_mime_docs), 3)
+
+        first_range_headers = got_mime_docs[0][0]
+        first_range_body = got_mime_docs[0][1]
+        self.assertEqual(first_range_headers['Content-Range'],
+                         'bytes 3-17/50')
+        self.assertEqual(first_range_headers['Content-Type'],
+                         'application/json')
+        self.assertEqual(first_range_body, 'aabbbbbbbbbbccc')
+
+        second_range_headers = got_mime_docs[1][0]
+        second_range_body = got_mime_docs[1][1]
+        self.assertEqual(second_range_headers['Content-Range'],
+                         'bytes 20-24/50')
+        self.assertEqual(second_range_headers['Content-Type'],
+                         'application/json')
+        self.assertEqual(second_range_body, 'ccccc')
+
+        third_range_headers = got_mime_docs[2][0]
+        third_range_body = got_mime_docs[2][1]
+        self.assertEqual(third_range_headers['Content-Range'],
+                         'bytes 35-49/50')
+        self.assertEqual(third_range_headers['Content-Type'],
+                         'application/json')
+        self.assertEqual(third_range_body, 'ddddddddddddddd')
+
+        self.assertEqual(
+            self.app.calls,
+            [('GET', '/v1/AUTH_test/gettest/manifest-abcd'),
+             ('GET', '/v1/AUTH_test/gettest/manifest-abcd'),
+             ('GET', '/v1/AUTH_test/gettest/manifest-bc'),
+             ('GET', '/v1/AUTH_test/gettest/a_5?multipart-manifest=get'),
+             ('GET', '/v1/AUTH_test/gettest/b_10?multipart-manifest=get'),
+             ('GET', '/v1/AUTH_test/gettest/c_15?multipart-manifest=get'),
+             ('GET', '/v1/AUTH_test/gettest/d_20?multipart-manifest=get')])
+
+        ranges = [c[2].get('Range') for c in self.app.calls_with_headers]
+        self.assertEqual(ranges, [
+            'bytes=3-17,20-24,35-999999',  # initial GET
+            None,                          # re-fetch top-level manifest
+            None,                          # fetch manifest-bc as sub-slo
+            'bytes=3-',                    # a_5
+            None,                          # b_10
+            'bytes=0-2,5-9',               # c_15
+            'bytes=5-'])                   # d_20
+        # we set swift.source for everything but the first request
+        self.assertIsNone(self.app.swift_sources[0])
+        self.assertEqual(self.app.swift_sources[1:],
+                         ['SLO'] * (len(self.app.swift_sources) - 1))
+
+    def test_multiple_ranges_including_suffix_get_manifest(self):
+        req = Request.blank(
+            '/v1/AUTH_test/gettest/manifest-abcd',
+            environ={'REQUEST_METHOD': 'GET'},
+            headers={'Range': 'bytes=3-17,-21'})
+        status, headers, body = self.call_slo(req)
+        headers = HeaderKeyDict(headers)
+
+        self.assertEqual(status, '206 Partial Content')
+
+        ct, params = parse_content_type(headers['Content-Type'])
+        params = dict(params)
+        self.assertEqual(ct, 'multipart/byteranges')
+        boundary = params.get('boundary')
+        self.assertTrue(boundary is not None)
+
+        got_mime_docs = []
+        for mime_doc_fh in iter_multipart_mime_documents(
+                StringIO(body), boundary):
+            headers = parse_mime_headers(mime_doc_fh)
+            body = mime_doc_fh.read()
+            got_mime_docs.append((headers, body))
+        self.assertEqual(len(got_mime_docs), 2)
+
+        first_range_headers = got_mime_docs[0][0]
+        first_range_body = got_mime_docs[0][1]
+        self.assertEqual(first_range_headers['Content-Range'],
+                         'bytes 3-17/50')
+        self.assertEqual(first_range_body, 'aabbbbbbbbbbccc')
+
+        second_range_headers = got_mime_docs[1][0]
+        second_range_body = got_mime_docs[1][1]
+        self.assertEqual(second_range_headers['Content-Range'],
+                         'bytes 29-49/50')
+        self.assertEqual(second_range_body, 'cdddddddddddddddddddd')
+
     def test_range_get_includes_whole_manifest(self):
         # If the first range GET results in retrieval of the entire manifest
         # body (which we can detect by looking at Content-Range), then we
@@ -1943,21 +2055,6 @@ class TestSloGetManifest(SloTestCase):
         status, headers, body = self.call_slo(req)
         self.assertEqual(status, '416 Requested Range Not Satisfiable')
 
-    def test_multi_range_get_manifest(self):
-        # SLO doesn't support multi-range GETs. The way that you express
-        # "unsupported" in HTTP is to return a 200 and the whole entity.
-        req = Request.blank(
-            '/v1/AUTH_test/gettest/manifest-abcd',
-            environ={'REQUEST_METHOD': 'GET'},
-            headers={'Range': 'bytes=0-0,2-2'})
-        status, headers, body = self.call_slo(req)
-        headers = HeaderKeyDict(headers)
-
-        self.assertEqual(status, '200 OK')
-        self.assertEqual(headers['Content-Length'], '50')
-        self.assertEqual(
-            body, 'aaaaabbbbbbbbbbcccccccccccccccdddddddddddddddddddd')
-
     def test_get_segment_with_non_ascii_path(self):
         segment_body = u"a møøse once bit my sister".encode("utf-8")
         self.app.register(
@@ -2046,11 +2143,9 @@ class TestSloGetManifest(SloTestCase):
              ('GET', '/v1/AUTH_test/gettest/manifest-bc-ranges'),
              ('GET', '/v1/AUTH_test/gettest/a_5?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/c_15?multipart-manifest=get'),
-             ('GET', '/v1/AUTH_test/gettest/manifest-bc-ranges'),
              ('GET', '/v1/AUTH_test/gettest/d_20?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/c_15?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/b_10?multipart-manifest=get'),
-             ('GET', '/v1/AUTH_test/gettest/manifest-bc-ranges'),
              ('GET', '/v1/AUTH_test/gettest/a_5?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/b_10?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/d_20?multipart-manifest=get')])
@@ -2062,11 +2157,9 @@ class TestSloGetManifest(SloTestCase):
             None,
             'bytes=3-',
             'bytes=0-2',
-            None,
             'bytes=11-11',
             'bytes=13-',
             'bytes=4-6',
-            None,
             'bytes=0-0',
             'bytes=4-5',
             'bytes=0-2'])
@@ -2133,11 +2226,9 @@ class TestSloGetManifest(SloTestCase):
              ('GET', '/v1/AUTH_test/gettest/manifest-abcd-ranges'),
              ('GET', '/v1/AUTH_test/gettest/manifest-bc-ranges'),
              ('GET', '/v1/AUTH_test/gettest/c_15?multipart-manifest=get'),
-             ('GET', '/v1/AUTH_test/gettest/manifest-bc-ranges'),
              ('GET', '/v1/AUTH_test/gettest/d_20?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/c_15?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/b_10?multipart-manifest=get'),
-             ('GET', '/v1/AUTH_test/gettest/manifest-bc-ranges'),
              ('GET', '/v1/AUTH_test/gettest/a_5?multipart-manifest=get'),
              ('GET', '/v1/AUTH_test/gettest/b_10?multipart-manifest=get')])
 
@@ -2148,11 +2239,9 @@ class TestSloGetManifest(SloTestCase):
             None,
             None,
             'bytes=2-2',
-            None,
             'bytes=11-11',
             'bytes=13-',
             'bytes=4-6',
-            None,
             'bytes=0-0',
             'bytes=4-4'])
         # we set swift.source for everything but the first request
@@ -2199,23 +2288,6 @@ class TestSloGetManifest(SloTestCase):
         self.assertEqual(self.app.swift_sources[1:],
                          ['SLO'] * (len(self.app.swift_sources) - 1))
 
-    def test_multi_range_get_range_manifest(self):
-        # SLO doesn't support multi-range GETs. The way that you express
-        # "unsupported" in HTTP is to return a 200 and the whole entity.
-        req = Request.blank(
-            '/v1/AUTH_test/gettest/manifest-abcd-ranges',
-            environ={'REQUEST_METHOD': 'GET'},
-            headers={'Range': 'bytes=0-0,2-2'})
-        status, headers, body = self.call_slo(req)
-        headers = HeaderKeyDict(headers)
-
-        self.assertEqual(status, '200 OK')
-        self.assertEqual(headers['Content-Type'], 'application/json')
-        self.assertEqual(body, 'aaaaaaaaccccccccbbbbbbbbdddddddd')
-        self.assertNotIn('Transfer-Encoding', headers)
-        self.assertNotIn('Content-Range', headers)
-        self.assertEqual(headers['Content-Length'], '32')
-
     def test_get_bogus_manifest(self):
         req = Request.blank(
             '/v1/AUTH_test/gettest/manifest-badjson',

test/unit/common/test_swob.py

@@ -1299,16 +1299,16 @@ class TestResponse(unittest.TestCase):
         resp = req.get_response(test_app)
         resp.conditional_response = True
         body = ''.join(resp([], start_response))
-        self.assertEqual(body, '')
-        self.assertEqual(resp.content_length, 0)
+        self.assertIn('The Range requested is not available', body)
+        self.assertEqual(resp.content_length, len(body))
         self.assertEqual(resp.status, '416 Requested Range Not Satisfiable')
 
         resp = swift.common.swob.Response(
             body='1234567890', request=req,
             conditional_response=True)
         body = ''.join(resp([], start_response))
-        self.assertEqual(body, '')
-        self.assertEqual(resp.content_length, 0)
+        self.assertIn('The Range requested is not available', body)
+        self.assertEqual(resp.content_length, len(body))
         self.assertEqual(resp.status, '416 Requested Range Not Satisfiable')
 
         # Syntactically-invalid Range headers "MUST" be ignored

test/unit/common/test_utils.py

@@ -5505,6 +5505,68 @@ class TestLRUCache(unittest.TestCase):
         self.assertEqual(f.size(), 4)
 
 
+class TestSpliterator(unittest.TestCase):
+    def test_string(self):
+        input_chunks = ["coun", "ter-", "b", "ra", "nch-mater",
+                        "nit", "y-fungusy", "-nummular"]
+        si = utils.Spliterator(input_chunks)
+
+        self.assertEqual(''.join(si.take(8)), "counter-")
+        self.assertEqual(''.join(si.take(7)), "branch-")
+        self.assertEqual(''.join(si.take(10)), "maternity-")
+        self.assertEqual(''.join(si.take(8)), "fungusy-")
+        self.assertEqual(''.join(si.take(8)), "nummular")
+
+    def test_big_input_string(self):
+        input_chunks = ["iridium"]
+        si = utils.Spliterator(input_chunks)
+
+        self.assertEqual(''.join(si.take(2)), "ir")
+        self.assertEqual(''.join(si.take(1)), "i")
+        self.assertEqual(''.join(si.take(2)), "di")
+        self.assertEqual(''.join(si.take(1)), "u")
+        self.assertEqual(''.join(si.take(1)), "m")
+
+    def test_chunk_boundaries(self):
+        input_chunks = ["soylent", "green", "is", "people"]
+        si = utils.Spliterator(input_chunks)
+
+        self.assertEqual(''.join(si.take(7)), "soylent")
+        self.assertEqual(''.join(si.take(5)), "green")
+        self.assertEqual(''.join(si.take(2)), "is")
+        self.assertEqual(''.join(si.take(6)), "people")
+
+    def test_no_empty_strings(self):
+        input_chunks = ["soylent", "green", "is", "people"]
+        si = utils.Spliterator(input_chunks)
+
+        outputs = (list(si.take(7))     # starts and ends on chunk boundary
+                   + list(si.take(2))   # spans two chunks
+                   + list(si.take(3))   # begins but does not end chunk
+                   + list(si.take(2))   # ends but does not begin chunk
+                   + list(si.take(6)))  # whole chunk + EOF
+        self.assertNotIn('', outputs)
+
+    def test_running_out(self):
+        input_chunks = ["not much"]
+        si = utils.Spliterator(input_chunks)
+
+        self.assertEqual(''.join(si.take(4)), "not ")
+        self.assertEqual(''.join(si.take(99)), "much")  # short
+        self.assertEqual(''.join(si.take(4)), "")
+        self.assertEqual(''.join(si.take(4)), "")
+
+    def test_overlap(self):
+        input_chunks = ["one fish", "two fish", "red fish", "blue fish"]
+
+        si = utils.Spliterator(input_chunks)
+        t1 = si.take(20)  # longer than first chunk
+        self.assertLess(len(next(t1)), 20)  # it's not exhausted
+
+        t2 = si.take(20)
+        self.assertRaises(ValueError, next, t2)
+
+
 class TestParseContentRange(unittest.TestCase):
     def test_good(self):
         start, end, total = utils.parse_content_range("bytes 100-200/300")