def read_share_chunk(
client: StorageClient,
share_type: str,
storage_index: bytes,
share_number: int,
offset: int,
length: int,
) -> Deferred[bytes]:
"""
Download a chunk of data from a share.
TODO https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3857 Failed downloads
should be transparently retried and redownloaded by the implementation a
few times so that if a failure percolates up, the caller can assume the
failure isn't a short-term blip.
NOTE: the underlying HTTP protocol is somewhat more flexible than this API,
insofar as it doesn't always require a range. In practice a range is
always provided by the current callers.
"""
url = client.relative_url("/v1/{}/{}/{}".format(share_type,
_encode_si(storage_index),
share_number))
response = yield client.request(
"GET",
url,
headers=Headers({
"range": [Range("bytes", [(offset, offset + length)]).to_header()]
}),
)
if response.code == http.PARTIAL_CONTENT:
body = yield response.content()
returnValue(body)
else:
raise ClientException(response.code)
async def test_response_make_conditional() -> None:
response = Response(b"abcdef")
await response.make_conditional(Range("bytes", [(0, 3)]))
assert b"abc" == (await response.get_data()) # type: ignore
assert response.status_code == 206
assert response.accept_ranges == "bytes"
assert response.content_range.units == "bytes"
assert response.content_range.start == 0
assert response.content_range.stop == 2
assert response.content_range.length == 6
def parse_range_header(value, make_inclusive=True):
"""Parses a range header into a :class:`~werkzeug.datastructures.Range`
object. If the header is missing or malformed `None` is returned.
`ranges` is a list of ``(start, stop)`` tuples where the ranges are
non-inclusive.
.. versionadded:: 0.7
"""
if not value or '=' not in value:
return None
ranges = []
last_end = 0
units, rng = value.split('=', 1)
units = units.strip().lower()
for item in rng.split(','):
item = item.strip()
if '-' not in item:
return None
if item.startswith('-'):
if last_end < 0:
return None
try:
begin = int(item)
except ValueError:
return None
end = None
last_end = -1
elif '-' in item:
begin, end = item.split('-', 1)
begin = begin.strip()
end = end.strip()
if not begin.isdigit():
return None
begin = int(begin)
if begin < last_end or last_end < 0:
return None
if end:
if not end.isdigit():
return None
end = int(end) + 1
if begin >= end:
return None
else:
end = None
last_end = end
ranges.append((begin, end))
return Range(units, ranges)
@pytest.mark.asyncio
async def test_response_make_conditional() -> None:
response = Response(b"abcdef")
await response.make_conditional(Range("bytes", [(0, 3)]))
assert b"abc" == (await response.get_data()) # type: ignore
assert response.status_code == 206
assert response.accept_ranges == "bytes"
assert response.content_range.units == "bytes"
assert response.content_range.start == 0
assert response.content_range.stop == 2
assert response.content_range.length == 6
@pytest.mark.asyncio
@pytest.mark.parametrize("range_", [Range("", {}), Range("bytes", [(0, 6)])])
async def test_response_make_conditional_no_condition(range_: Range) -> None:
response = Response(b"abcdef")
await response.make_conditional(range_)
assert b"abcdef" == (await response.get_data()) # type: ignore
assert response.status_code == 200
assert response.accept_ranges == "bytes"
@pytest.mark.asyncio
@pytest.mark.parametrize(
"range_",
[
Range("seconds", [(0, 3)]),
Range("bytes", [(0, 2), (3, 5)]),
Range("bytes", [(0, 8)])
def test_range_to_header(ranges):
header = Range("byes", ranges).to_header()
r = http.parse_range_header(header)
assert r.ranges == ranges
