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# -*- coding: utf-8 -*-
# support.py
# Copyright (C) 2015 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import warnings
import json
from twisted.internet import defer
from twisted.web.client import _ReadBodyProtocol
from twisted.web.client import PartialDownloadError
from twisted.web._newclient import ResponseDone
from twisted.web._newclient import PotentialDataLoss
from leap.soledad.common.l2db import errors
from leap.soledad.common.l2db.remote import http_errors
# we want to make sure that HTTP errors will raise appropriate u1db errors,
# that is, fire errbacks with the appropriate failures, in the context of
# twisted. Because of that, we redefine the http body reader used by the HTTP
# client below.
class ReadBodyProtocol(_ReadBodyProtocol):
"""
From original Twisted implementation, focused on adding our error
handling and ensuring that the proper u1db error is raised.
"""
def __init__(self, response, deferred):
"""
Initialize the protocol, additionally storing the response headers.
"""
_ReadBodyProtocol.__init__(
self, response.code, response.phrase, deferred)
self.headers = response.headers
# ---8<--- snippet from u1db.remote.http_client, modified to use errbacks
def _error(self, respdic):
descr = respdic.get("error")
exc_cls = errors.wire_description_to_exc.get(descr)
if exc_cls is not None:
message = respdic.get("message")
self.deferred.errback(exc_cls(message))
else:
self.deferred.errback(
errors.HTTPError(self.status, respdic, self.headers))
# ---8<--- end of snippet from u1db.remote.http_client
def connectionLost(self, reason):
"""
Deliver the accumulated response bytes to the waiting L{Deferred}, if
the response body has been completely received without error.
"""
if reason.check(ResponseDone):
body = b''.join(self.dataBuffer)
# ---8<--- snippet from u1db.remote.http_client
if self.status in (200, 201):
self.deferred.callback(body)
elif self.status in http_errors.ERROR_STATUSES:
try:
respdic = json.loads(body)
except ValueError:
self.deferred.errback(
errors.HTTPError(self.status, body, self.headers))
else:
self._error(respdic)
# special cases
elif self.status == 503:
self.deferred.errback(errors.Unavailable(body, self.headers))
else:
self.deferred.errback(
errors.HTTPError(self.status, body, self.headers))
# ---8<--- end of snippet from u1db.remote.http_client
elif reason.check(PotentialDataLoss):
self.deferred.errback(
PartialDownloadError(self.status, self.message,
b''.join(self.dataBuffer)))
else:
self.deferred.errback(reason)
def readBody(response, protocolClass=ReadBodyProtocol):
"""
Get the body of an L{IResponse} and return it as a byte string.
This is a helper function for clients that don't want to incrementally
receive the body of an HTTP response.
@param response: The HTTP response for which the body will be read.
@type response: L{IResponse} provider
@return: A L{Deferred} which will fire with the body of the response.
Cancelling it will close the connection to the server immediately.
"""
def cancel(deferred):
"""
Cancel a L{readBody} call, close the connection to the HTTP server
immediately, if it is still open.
@param deferred: The cancelled L{defer.Deferred}.
"""
abort = getAbort()
if abort is not None:
abort()
d = defer.Deferred(cancel)
protocol = protocolClass(response, d)
def getAbort():
return getattr(protocol.transport, 'abortConnection', None)
response.deliverBody(protocol)
if protocol.transport is not None and getAbort() is None:
warnings.warn(
'Using readBody with a transport that does not have an '
'abortConnection method',
category=DeprecationWarning,
stacklevel=2)
return d
class RequestBody(object):
"""
This class is a helper to generate send and fetch requests.
The expected format is something like:
[
{headers},
{entry1},
{...},
{entryN},
]
"""
def __init__(self, **header_dict):
"""
Creates a new RequestBody holding header information.
:param header_dict: A dictionary with the headers.
:type header_dict: dict
"""
self.headers = header_dict
self.entries = []
self.consumed = 0
def insert_info(self, **entry_dict):
"""
Dumps an entry into JSON format and add it to entries list.
Adds 'content' key on a new line if it's present.
:param entry_dict: Entry as a dictionary
:type entry_dict: dict
"""
content = ''
if 'content' in entry_dict:
content = ',\r\n' + (entry_dict['content'] or '')
entry = json.dumps(entry_dict) + content
self.entries.append(entry)
def pop(self, amount=10, leave_open=False):
"""
Removes entries and returns it formatted and ready
to be sent.
:param amount: number of entries to pop and format
:type amount: int
:param leave_open: flag to skip stream closing
:type amount: bool
:return: formatted body ready to be sent
:rtype: str
"""
start = self.consumed == 0
amount = min([len(self.entries), amount])
entries = [self.entries.pop(0) for i in xrange(amount)]
self.consumed += amount
end = len(self.entries) == 0 if not leave_open else False
return self.entries_to_str(entries, start, end)
def __str__(self):
return self.pop(len(self.entries))
def __len__(self):
return len(self.entries)
def entries_to_str(self, entries=None, start=True, end=True):
"""
Format a list of entries into the body format expected
by the server.
:param entries: entries to format
:type entries: list
:return: formatted body ready to be sent
:rtype: str
"""
data = ''
if start:
data = '[\r\n' + json.dumps(self.headers)
data += ''.join(',\r\n' + entry for entry in entries)
if end:
data += '\r\n]'
return data
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