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# -*- coding: utf-8 -*-
# _blobs.py
# Copyright (C) 2017 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/>.
"""
Blobs Server implementation.
This is a very simplistic implementation for the time being.
Clients should be able to opt-in util the feature is complete.
A more performant BlobsBackend can (and should) be implemented for production
environments.
"""
import os
import base64
import json
import re
from twisted.logger import Logger
from twisted.web import static
from twisted.web import resource
from twisted.web.client import FileBodyProducer
from twisted.web.server import NOT_DONE_YET
from twisted.internet import utils, defer
from zope.interface import implementer
from leap.common.files import mkdir_p
from leap.soledad.server import interfaces
__all__ = ['BlobsResource']
logger = Logger()
# Used for sanitizers, we accept only letters, numbers, '-' and '_'
VALID_STRINGS = re.compile('^[a-zA-Z0-9_-]+$')
# for the future:
# [ ] isolate user avatar in a safer way
# [ ] catch timeout in the server (and delete incomplete upload)
# [ ] chunking (should we do it on the client or on the server?)
@implementer(interfaces.IBlobsBackend)
class FilesystemBlobsBackend(object):
def __init__(self, blobs_path='/tmp/blobs/', quota=200 * 1024):
self.quota = quota
if not os.path.isdir(blobs_path):
os.makedirs(blobs_path)
self.path = blobs_path
def read_blob(self, user, blob_id, request, namespace=''):
logger.info('reading blob: %s - %s' % (user, blob_id))
path = self._get_path(user, blob_id, namespace)
logger.debug('blob path: %s' % path)
_file = static.File(path, defaultType='application/octet-stream')
return _file.render_GET(request)
@defer.inlineCallbacks
def write_blob(self, user, blob_id, request, namespace=''):
path = self._get_path(user, blob_id, namespace)
try:
mkdir_p(os.path.split(path)[0])
except OSError:
pass
if os.path.isfile(path):
# 409 - Conflict
request.setResponseCode(409)
request.write("Blob already exists: %s" % blob_id)
defer.returnValue(None)
used = yield self.get_total_storage(user)
if used > self.quota:
logger.error("Error 507: Quota exceeded for user: %s" % user)
request.setResponseCode(507)
request.write('Quota Exceeded!')
defer.returnValue(None)
logger.info('writing blob: %s - %s' % (user, blob_id))
fbp = FileBodyProducer(request.content)
yield fbp.startProducing(open(path, 'wb'))
def delete_blob(self, user, blob_id, namespace=''):
blob_path = self._get_path(user, blob_id, namespace)
os.unlink(blob_path)
def get_blob_size(user, blob_id, namespace=''):
raise NotImplementedError
def list_blobs(self, user, request, namespace=''):
blob_ids = []
base_path = self._get_path(user, custom_preffix=namespace)
for _, _, filenames in os.walk(base_path):
blob_ids += filenames
return json.dumps(blob_ids)
def get_total_storage(self, user):
return self._get_disk_usage(self._get_path(user))
def add_tag_header(self, user, blob_id, request, namespace=''):
with open(self._get_path(user, blob_id, namespace)) as doc_file:
doc_file.seek(-16, 2)
tag = base64.urlsafe_b64encode(doc_file.read())
request.responseHeaders.setRawHeaders('Tag', [tag])
@defer.inlineCallbacks
def _get_disk_usage(self, start_path):
if not os.path.isdir(start_path):
defer.returnValue(0)
cmd = ['/usr/bin/du', '-s', '-c', start_path]
output = yield utils.getProcessOutput(cmd[0], cmd[1:])
size = output.split()[0]
defer.returnValue(int(size))
def _validate_path(self, desired_path, user, blob_id):
if not VALID_STRINGS.match(user):
raise Exception("Invalid characters on user: %s" % user)
if blob_id and not VALID_STRINGS.match(blob_id):
raise Exception("Invalid characters on blob_id: %s" % blob_id)
desired_path = os.path.realpath(desired_path) # expand path references
root = os.path.realpath(self.path)
if not desired_path.startswith(root + os.sep + user):
err = "User %s tried accessing a invalid path: %s" % (user,
desired_path)
raise Exception(err)
return desired_path
def _get_path(self, user, blob_id='', custom_preffix=''):
parts = [user]
parts += self._get_preffix(blob_id, custom_preffix)
if blob_id:
parts += [blob_id]
path = os.path.join(self.path, *parts)
return self._validate_path(path, user, blob_id)
def _get_preffix(self, blob_id, custom=''):
if custom or not blob_id:
return [custom]
return [blob_id[0], blob_id[0:3], blob_id[0:6]]
class ImproperlyConfiguredException(Exception):
pass
class BlobsResource(resource.Resource):
isLeaf = True
# Allowed backend classes are defined here
handlers = {"filesystem": FilesystemBlobsBackend}
def __init__(self, backend, blobs_path, **backend_kwargs):
resource.Resource.__init__(self)
self._blobs_path = blobs_path
backend_kwargs.update({'blobs_path': blobs_path})
if backend not in self.handlers:
raise ImproperlyConfiguredException("No such backend: %s", backend)
self._handler = self.handlers[backend](**backend_kwargs)
assert interfaces.IBlobsBackend.providedBy(self._handler)
# TODO double check credentials, we can have then
# under request.
def render_GET(self, request):
logger.info("http get: %s" % request.path)
user, blob_id = self._validate(request)
if not blob_id:
return self._handler.list_blobs(user, request)
self._handler.add_tag_header(user, blob_id, request)
return self._handler.read_blob(user, blob_id, request)
def render_DELETE(self, request):
logger.info("http put: %s" % request.path)
user, blob_id = self._validate(request)
self._handler.delete_blob(user, blob_id)
return ''
def render_PUT(self, request):
logger.info("http put: %s" % request.path)
user, blob_id = self._validate(request)
d = self._handler.write_blob(user, blob_id, request)
d.addCallback(lambda _: request.finish())
d.addErrback(self._error, request)
return NOT_DONE_YET
def _error(self, e, request):
logger.error('Error processing request: %s' % e.getErrorMessage())
request.setResponseCode(500)
request.finish()
def _validate(self, request):
for arg in request.postpath:
if arg and not VALID_STRINGS.match(arg):
raise Exception('Invalid blob resource argument: %s' % arg)
return request.postpath
if __name__ == '__main__':
# A dummy blob server
# curl -X PUT --data-binary @/tmp/book.pdf localhost:9000/user/someid
# curl -X GET -o /dev/null localhost:9000/user/somerandomstring
from twisted.python import log
import sys
log.startLogging(sys.stdout)
from twisted.web.server import Site
from twisted.internet import reactor
# parse command line arguments
import argparse
parser = argparse.ArgumentParser()
parser.add_argument('--port', default=9000, type=int)
parser.add_argument('--path', default='/tmp/blobs/user')
args = parser.parse_args()
root = BlobsResource("filesystem", args.path)
# I picture somethink like
# BlobsResource(backend="filesystem", backend_opts={'path': '/tmp/blobs'})
factory = Site(root)
reactor.listenTCP(args.port, factory)
reactor.run()
class BlobsServerState(object):
"""
Given a backend name, it gives a instance of IBlobsBackend
"""
# Allowed backend classes are defined here
handlers = {"filesystem": FilesystemBlobsBackend}
def __init__(self, backend, **backend_kwargs):
if backend not in self.handlers:
raise ImproperlyConfiguredException("No such backend: %s", backend)
self.backend = self.handlers[backend](**backend_kwargs)
def open_database(self, user_id):
"""
That method is just for compatibility with CouchServerState, so
IncomingAPI can change backends.
"""
return self.backend
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