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# Copyright (C) 2005, 2006, 2007 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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"""Base implementation of Transport over http.
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There are separate implementation modules for each http client implementation.
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from cStringIO import StringIO
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from bzrlib.smart import medium
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from bzrlib.symbol_versioning import (
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from bzrlib.trace import mutter
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from bzrlib.transport import (
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# TODO: This is not used anymore by HttpTransport_urllib
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# (extracting the auth info and prompting the user for a password
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# have been split), only the tests still use it. It should be
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# deleted and the tests rewritten ASAP to stay in sync.
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def extract_auth(url, password_manager):
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"""Extract auth parameters from am HTTP/HTTPS url and add them to the given
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password manager. Return the url, minus those auth parameters (which
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if not re.match(r'^(https?)(\+\w+)?://', url):
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'invalid absolute url %r' % (url,))
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scheme, netloc, path, query, fragment = urlparse.urlsplit(url)
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auth, netloc = netloc.split('@', 1)
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username, password = auth.split(':', 1)
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username, password = auth, None
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host = netloc.split(':', 1)[0]
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username = urllib.unquote(username)
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if password is not None:
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password = urllib.unquote(password)
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password = ui.ui_factory.get_password(
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prompt='HTTP %(user)s@%(host)s password',
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user=username, host=host)
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password_manager.add_password(None, host, username, password)
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url = urlparse.urlunsplit((scheme, netloc, path, query, fragment))
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class HttpTransportBase(ConnectedTransport):
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"""Base class for http implementations.
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Does URL parsing, etc, but not any network IO.
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The protocol can be given as e.g. http+urllib://host/ to use a particular
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# _unqualified_scheme: "http" or "https"
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# _scheme: may have "+pycurl", etc
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def __init__(self, base, _from_transport=None):
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"""Set the base path where files will be stored."""
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proto_match = re.match(r'^(https?)(\+\w+)?://', base)
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raise AssertionError("not a http url: %r" % base)
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self._unqualified_scheme = proto_match.group(1)
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impl_name = proto_match.group(2)
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impl_name = impl_name[1:]
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self._impl_name = impl_name
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super(HttpTransportBase, self).__init__(base,
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_from_transport=_from_transport)
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# range hint is handled dynamically throughout the life
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# of the transport object. We start by trying multi-range
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# requests and if the server returns bogus results, we
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# retry with single range requests and, finally, we
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# forget about range if the server really can't
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# understand. Once acquired, this piece of info is
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# propagated to clones.
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if _from_transport is not None:
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self._range_hint = _from_transport._range_hint
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self._range_hint = 'multi'
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def has(self, relpath):
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raise NotImplementedError("has() is abstract on %r" % self)
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def get(self, relpath):
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"""Get the file at the given relative path.
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:param relpath: The relative path to the file
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code, response_file = self._get(relpath, None)
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# FIXME: some callers want an iterable... One step forward, three steps
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# backwards :-/ And not only an iterable, but an iterable that can be
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# seeked backwards, so we will never be able to do that. One such
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# known client is bzrlib.bundle.serializer.v4.get_bundle_reader. At the
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# time of this writing it's even the only known client -- vila20071203
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return StringIO(response_file.read())
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def _get(self, relpath, ranges, tail_amount=0):
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"""Get a file, or part of a file.
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:param relpath: Path relative to transport base URL
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:param ranges: None to get the whole file;
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or a list of _CoalescedOffset to fetch parts of a file.
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:param tail_amount: The amount to get from the end of the file.
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:returns: (http_code, result_file)
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raise NotImplementedError(self._get)
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def _remote_path(self, relpath):
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"""See ConnectedTransport._remote_path.
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user and passwords are not embedded in the path provided to the server.
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relative = urlutils.unescape(relpath).encode('utf-8')
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path = self._combine_paths(self._path, relative)
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return self._unsplit_url(self._unqualified_scheme,
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None, None, self._host, self._port, path)
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def _create_auth(self):
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"""Returns a dict returning the credentials provided at build time."""
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auth = dict(host=self._host, port=self._port,
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user=self._user, password=self._password,
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protocol=self._unqualified_scheme,
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def get_smart_medium(self):
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"""See Transport.get_smart_medium."""
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if self._medium is None:
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# Since medium holds some state (smart server probing at least), we
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# need to keep it around. Note that this is needed because medium
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# has the same 'base' attribute as the transport so it can't be
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# shared between transports having different bases.
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self._medium = SmartClientHTTPMedium(self)
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def _degrade_range_hint(self, relpath, ranges, exc_info):
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if self._range_hint == 'multi':
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self._range_hint = 'single'
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mutter('Retry "%s" with single range request' % relpath)
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elif self._range_hint == 'single':
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self._range_hint = None
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mutter('Retry "%s" without ranges' % relpath)
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# We tried all the tricks, but nothing worked. We re-raise the
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# original exception; the 'mutter' calls above will indicate that
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# further tries were unsuccessful
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raise exc_info[0], exc_info[1], exc_info[2]
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# _coalesce_offsets is a helper for readv, it try to combine ranges without
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# degrading readv performances. _bytes_to_read_before_seek is the value
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# used for the limit parameter and has been tuned for other transports. For
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# HTTP, the name is inappropriate but the parameter is still useful and
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# helps reduce the number of chunks in the response. The overhead for a
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# chunk (headers, length, footer around the data itself is variable but
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# around 50 bytes. We use 128 to reduce the range specifiers that appear in
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# the header, some servers (notably Apache) enforce a maximum length for a
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# header and issue a '400: Bad request' error when too much ranges are
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_bytes_to_read_before_seek = 128
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# No limit on the offset number that get combined into one, we are trying
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# to avoid downloading the whole file.
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_max_readv_combine = 0
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# By default Apache has a limit of ~400 ranges before replying with a 400
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# Bad Request. So we go underneath that amount to be safe.
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_max_get_ranges = 200
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# We impose no limit on the range size. But see _pycurl.py for a different
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def _readv(self, relpath, offsets):
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"""Get parts of the file at the given relative path.
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:param offsets: A list of (offset, size) tuples.
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:param return: A list or generator of (offset, data) tuples
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# offsets may be a generator, we will iterate it several times, so
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offsets = list(offsets)
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retried_offset = None
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# Coalesce the offsets to minimize the GET requests issued
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sorted_offsets = sorted(offsets)
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coalesced = self._coalesce_offsets(
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sorted_offsets, limit=self._max_readv_combine,
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fudge_factor=self._bytes_to_read_before_seek,
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max_size=self._get_max_size)
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# Turn it into a list, we will iterate it several times
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coalesced = list(coalesced)
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if 'http' in debug.debug_flags:
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mutter('http readv of %s offsets => %s collapsed %s',
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relpath, len(offsets), len(coalesced))
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# Cache the data read, but only until it's been used
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# We will iterate on the data received from the GET requests and
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# serve the corresponding offsets respecting the initial order. We
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# need an offset iterator for that.
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iter_offsets = iter(offsets)
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cur_offset_and_size = iter_offsets.next()
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for cur_coal, rfile in self._coalesce_readv(relpath, coalesced):
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# Split the received chunk
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for offset, size in cur_coal.ranges:
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start = cur_coal.start + offset
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data = rfile.read(size)
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raise errors.ShortReadvError(relpath, start, size,
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if (start, size) == cur_offset_and_size:
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# The offset requested are sorted as the coalesced
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# ones, no need to cache. Win !
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yield cur_offset_and_size[0], data
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cur_offset_and_size = iter_offsets.next()
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# Different sorting. We need to cache.
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data_map[(start, size)] = data
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# Yield everything we can
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while cur_offset_and_size in data_map:
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# Clean the cached data since we use it
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# XXX: will break if offsets contains duplicates --
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this_data = data_map.pop(cur_offset_and_size)
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yield cur_offset_and_size[0], this_data
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cur_offset_and_size = iter_offsets.next()
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except (errors.ShortReadvError, errors.InvalidRange,
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errors.InvalidHttpRange), e:
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mutter('Exception %r: %s during http._readv',e, e)
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if (not isinstance(e, errors.ShortReadvError)
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or retried_offset == cur_offset_and_size):
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# We don't degrade the range hint for ShortReadvError since
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# they do not indicate a problem with the server ability to
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# handle ranges. Except when we fail to get back a required
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# offset twice in a row. In that case, falling back to
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# single range or whole file should help or end up in a
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self._degrade_range_hint(relpath, coalesced, sys.exc_info())
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# Some offsets may have been already processed, so we retry
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# only the unsuccessful ones.
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offsets = [cur_offset_and_size] + [o for o in iter_offsets]
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retried_offset = cur_offset_and_size
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def _coalesce_readv(self, relpath, coalesced):
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"""Issue several GET requests to satisfy the coalesced offsets"""
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def get_and_yield(relpath, coalesced):
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# Note that the _get below may raise
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# errors.InvalidHttpRange. It's the caller's responsibility to
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# decide how to retry since it may provide different coalesced
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code, rfile = self._get(relpath, coalesced)
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for coal in coalesced:
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if self._range_hint is None:
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# Download whole file
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for c, rfile in get_and_yield(relpath, coalesced):
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total = len(coalesced)
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if self._range_hint == 'multi':
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max_ranges = self._max_get_ranges
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elif self._range_hint == 'single':
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raise AssertionError("Unknown _range_hint %r"
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% (self._range_hint,))
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# TODO: Some web servers may ignore the range requests and return
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# the whole file, we may want to detect that and avoid further
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# Hint: test_readv_multiple_get_requests will fail once we do that
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for coal in coalesced:
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if ((self._get_max_size > 0
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and cumul + coal.length > self._get_max_size)
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or len(ranges) >= max_ranges):
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# Get that much and yield
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for c, rfile in get_and_yield(relpath, ranges):
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# Restart with the current offset
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# Get the rest and yield
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for c, rfile in get_and_yield(relpath, ranges):
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def recommended_page_size(self):
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"""See Transport.recommended_page_size().
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For HTTP we suggest a large page size to reduce the overhead
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introduced by latency.
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def _post(self, body_bytes):
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"""POST body_bytes to .bzr/smart on this transport.
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:returns: (response code, response body file-like object).
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# TODO: Requiring all the body_bytes to be available at the beginning of
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# the POST may require large client buffers. It would be nice to have
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# an interface that allows streaming via POST when possible (and
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# degrades to a local buffer when not).
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raise NotImplementedError(self._post)
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def put_file(self, relpath, f, mode=None):
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"""Copy the file-like object into the location.
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:param relpath: Location to put the contents, relative to base.
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:param f: File-like object.
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raise errors.TransportNotPossible('http PUT not supported')
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def mkdir(self, relpath, mode=None):
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"""Create a directory at the given path."""
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raise errors.TransportNotPossible('http does not support mkdir()')
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def rmdir(self, relpath):
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"""See Transport.rmdir."""
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raise errors.TransportNotPossible('http does not support rmdir()')
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def append_file(self, relpath, f, mode=None):
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"""Append the text in the file-like object into the final
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raise errors.TransportNotPossible('http does not support append()')
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def copy(self, rel_from, rel_to):
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"""Copy the item at rel_from to the location at rel_to"""
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raise errors.TransportNotPossible('http does not support copy()')
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def copy_to(self, relpaths, other, mode=None, pb=None):
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"""Copy a set of entries from self into another Transport.
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:param relpaths: A list/generator of entries to be copied.
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TODO: if other is LocalTransport, is it possible to
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do better than put(get())?
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# At this point HttpTransport might be able to check and see if
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# the remote location is the same, and rather than download, and
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# then upload, it could just issue a remote copy_this command.
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if isinstance(other, HttpTransportBase):
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raise errors.TransportNotPossible(
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'http cannot be the target of copy_to()')
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return super(HttpTransportBase, self).\
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copy_to(relpaths, other, mode=mode, pb=pb)
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def move(self, rel_from, rel_to):
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"""Move the item at rel_from to the location at rel_to"""
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raise errors.TransportNotPossible('http does not support move()')
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def delete(self, relpath):
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"""Delete the item at relpath"""
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raise errors.TransportNotPossible('http does not support delete()')
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def external_url(self):
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"""See bzrlib.transport.Transport.external_url."""
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# HTTP URL's are externally usable.
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def is_readonly(self):
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"""See Transport.is_readonly."""
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"""See Transport.listable."""
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def stat(self, relpath):
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"""Return the stat information for a file.
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raise errors.TransportNotPossible('http does not support stat()')
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def lock_read(self, relpath):
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"""Lock the given file for shared (read) access.
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:return: A lock object, which should be passed to Transport.unlock()
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# The old RemoteBranch ignore lock for reading, so we will
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# continue that tradition and return a bogus lock object.
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class BogusLock(object):
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def __init__(self, path):
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return BogusLock(relpath)
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def lock_write(self, relpath):
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"""Lock the given file for exclusive (write) access.
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WARNING: many transports do not support this, so trying avoid using it
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:return: A lock object, which should be passed to Transport.unlock()
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raise errors.TransportNotPossible('http does not support lock_write()')
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def clone(self, offset=None):
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"""Return a new HttpTransportBase with root at self.base + offset
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We leave the daughter classes take advantage of the hint
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that it's a cloning not a raw creation.
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return self.__class__(self.base, self)
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return self.__class__(self.abspath(offset), self)
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def _attempted_range_header(self, offsets, tail_amount):
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"""Prepare a HTTP Range header at a level the server should accept.
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:return: the range header representing offsets/tail_amount or None if
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no header can be built.
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if self._range_hint == 'multi':
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# Generate the header describing all offsets
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return self._range_header(offsets, tail_amount)
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elif self._range_hint == 'single':
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# Combine all the requested ranges into a single
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if tail_amount not in (0, None):
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# Nothing we can do here to combine ranges with tail_amount
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# in a single range, just returns None. The whole file
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# should be downloaded.
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start = offsets[0].start
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end = last.start + last.length - 1
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whole = self._coalesce_offsets([(start, end - start + 1)],
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limit=0, fudge_factor=0)
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return self._range_header(list(whole), 0)
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# Only tail_amount, requested, leave range_header
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return self._range_header(offsets, tail_amount)
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def _range_header(ranges, tail_amount):
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"""Turn a list of bytes ranges into a HTTP Range header value.
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:param ranges: A list of _CoalescedOffset
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:param tail_amount: The amount to get from the end of the file.
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:return: HTTP range header string.
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At least a non-empty ranges *or* a tail_amount must be
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for offset in ranges:
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strings.append('%d-%d' % (offset.start,
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offset.start + offset.length - 1))
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strings.append('-%d' % tail_amount)
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return ','.join(strings)
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# TODO: May be better located in smart/medium.py with the other
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# SmartMedium classes
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class SmartClientHTTPMedium(medium.SmartClientMedium):
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def __init__(self, http_transport):
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super(SmartClientHTTPMedium, self).__init__(http_transport.base)
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# We don't want to create a circular reference between the http
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# transport and its associated medium. Since the transport will live
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# longer than the medium, the medium keep only a weak reference to its
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self._http_transport_ref = weakref.ref(http_transport)
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def get_request(self):
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return SmartClientHTTPMediumRequest(self)
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def should_probe(self):
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def remote_path_from_transport(self, transport):
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# Strip the optional 'bzr+' prefix from transport so it will have the
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# same scheme as self.
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transport_base = transport.base
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if transport_base.startswith('bzr+'):
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transport_base = transport_base[4:]
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rel_url = urlutils.relative_url(self.base, transport_base)
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return urllib.unquote(rel_url)
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def send_http_smart_request(self, bytes):
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# Get back the http_transport hold by the weak reference
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t = self._http_transport_ref()
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code, body_filelike = t._post(bytes)
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raise InvalidHttpResponse(
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t._remote_path('.bzr/smart'),
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'Expected 200 response code, got %r' % (code,))
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except errors.InvalidHttpResponse, e:
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raise errors.SmartProtocolError(str(e))
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# TODO: May be better located in smart/medium.py with the other
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# SmartMediumRequest classes
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class SmartClientHTTPMediumRequest(medium.SmartClientMediumRequest):
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"""A SmartClientMediumRequest that works with an HTTP medium."""
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def __init__(self, client_medium):
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medium.SmartClientMediumRequest.__init__(self, client_medium)
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def _accept_bytes(self, bytes):
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self._buffer += bytes
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def _finished_writing(self):
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data = self._medium.send_http_smart_request(self._buffer)
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self._response_body = data
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def _read_bytes(self, count):
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"""See SmartClientMediumRequest._read_bytes."""
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return self._response_body.read(count)
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def _read_line(self):
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line, excess = medium._get_line(self._response_body.read)
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raise AssertionError(
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'_get_line returned excess bytes, but this mediumrequest '
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'cannot handle excess. (%r)' % (excess,))
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def _finished_reading(self):
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"""See SmartClientMediumRequest._finished_reading."""
added
removed
bzrlib/transport/http/__init__.py
