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# Copyright 2009-2010 Canonical Ltd. This software is licensed under the
# GNU Affero General Public License version 3 (see the file LICENSE).
__metaclass__ = type
import os
import errno
import hashlib
import shutil
import tempfile
from zope.component import getUtility
from canonical.launchpad.webapp.interfaces import (
IStoreSelector, MAIN_STORE, DEFAULT_FLAVOR)
from lp.services.database import write_transaction
__all__ = [
'DigestMismatchError',
'LibrarianStorage',
'LibraryFileUpload',
'DuplicateFileIDError',
'WrongDatabaseError',
# _relFileLocation needed by other modules in this package.
# Listed here to keep the import fascist happy
'_relFileLocation',
'_sameFile',
]
class DigestMismatchError(Exception):
"""The given digest doesn't match the SHA-1 digest of the file."""
class DuplicateFileIDError(Exception):
"""Given File ID already exists."""
class WrongDatabaseError(Exception):
"""The client's database name doesn't match our database."""
def __init__(self, clientDatabaseName, serverDatabaseName):
Exception.__init__(self, clientDatabaseName, serverDatabaseName)
self.clientDatabaseName = clientDatabaseName
self.serverDatabaseName = serverDatabaseName
class LibrarianStorage:
"""Blob storage.
This manages the actual storage of files on disk and the record of those
in the database; it has nothing to do with the network interface to those
files.
"""
def __init__(self, directory, library):
self.directory = directory
self.library = library
self.incoming = os.path.join(self.directory, 'incoming')
try:
os.mkdir(self.incoming)
except OSError, e:
if e.errno != errno.EEXIST:
raise
def hasFile(self, fileid):
return os.access(self._fileLocation(fileid), os.F_OK)
def _fileLocation(self, fileid):
return os.path.join(self.directory, _relFileLocation(str(fileid)))
def startAddFile(self, filename, size):
return LibraryFileUpload(self, filename, size)
def getFileAlias(self, aliasid, token, path):
return self.library.getAlias(aliasid, token, path)
class LibraryFileUpload(object):
"""A file upload from a client."""
srcDigest = None
mimetype = 'unknown/unknown'
contentID = None
aliasID = None
expires = None
databaseName = None
debugID = None
def __init__(self, storage, filename, size):
self.storage = storage
self.filename = filename
self.size = size
self.debugLog = []
# Create temporary file
tmpfile, tmpfilepath = tempfile.mkstemp(dir=self.storage.incoming)
self.tmpfile = os.fdopen(tmpfile, 'w')
self.tmpfilepath = tmpfilepath
self.shaDigester = hashlib.sha1()
self.md5Digester = hashlib.md5()
def append(self, data):
self.tmpfile.write(data)
self.shaDigester.update(data)
self.md5Digester.update(data)
@write_transaction
def store(self):
self.debugLog.append('storing %r, size %r'
% (self.filename, self.size))
self.tmpfile.close()
# Verify the digest matches what the client sent us
dstDigest = self.shaDigester.hexdigest()
if self.srcDigest is not None and dstDigest != self.srcDigest:
# XXX: Andrew Bennetts 2004-09-20: Write test that checks that
# the file really is removed or renamed, and can't possibly be
# left in limbo
os.remove(self.tmpfilepath)
raise DigestMismatchError(self.srcDigest, dstDigest)
try:
# If the client told us the name of the database it's using,
# check that it matches.
if self.databaseName is not None:
store = getUtility(IStoreSelector).get(
MAIN_STORE, DEFAULT_FLAVOR)
result = store.execute("SELECT current_database()")
databaseName = result.get_one()[0]
if self.databaseName != databaseName:
raise WrongDatabaseError(self.databaseName, databaseName)
self.debugLog.append(
'database name %r ok' % (self.databaseName, ))
# If we haven't got a contentID, we need to create one and return
# it to the client.
if self.contentID is None:
contentID = self.storage.library.add(
dstDigest, self.size, self.md5Digester.hexdigest())
aliasID = self.storage.library.addAlias(
contentID, self.filename, self.mimetype, self.expires)
self.debugLog.append('created contentID: %r, aliasID: %r.'
% (contentID, aliasID))
else:
contentID = self.contentID
aliasID = None
self.debugLog.append('received contentID: %r' % (contentID, ))
except:
# Abort transaction and re-raise
self.debugLog.append('failed to get contentID/aliasID, aborting')
raise
# Move file to final location
try:
self._move(contentID)
except:
# Abort DB transaction
self.debugLog.append('failed to move file, aborting')
# Remove file
os.remove(self.tmpfilepath)
# Re-raise
raise
# Commit any DB changes
self.debugLog.append('committed')
# Return the IDs if we created them, or None otherwise
return contentID, aliasID
def _move(self, fileID):
location = self.storage._fileLocation(fileID)
if os.path.exists(location):
raise DuplicateFileIDError(fileID)
try:
os.makedirs(os.path.dirname(location))
except OSError, e:
# If the directory already exists, that's ok.
if e.errno != errno.EEXIST:
raise
shutil.move(self.tmpfilepath, location)
def _sameFile(path1, path2):
file1 = open(path1, 'rb')
file2 = open(path2, 'rb')
blk = 1024 * 64
chunksIter = iter(lambda: (file1.read(blk), file2.read(blk)), ('', ''))
for chunk1, chunk2 in chunksIter:
if chunk1 != chunk2:
return False
return True
def _relFileLocation(file_id):
"""Return the relative location for the given file_id.
The relative location is obtained by converting file_id into a 8-digit hex
and then splitting it across four path segments.
"""
h = "%08x" % int(file_id)
return '%s/%s/%s/%s' % (h[:2], h[2:4], h[4:6], h[6:])
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