# -*- coding: utf-8 -*- ############################################################################## # # Copyright (c) 2010 Nexedi SA and Contributors. All Rights Reserved. # Nicolas Delaby <nicolas@nexedi.com> # # WARNING: This program as such is intended to be used by professional # programmers who take the whole responsability of assessing all potential # consequences resulting from its eventual inadequacies and bugs # End users who are looking for a ready-to-use solution with commercial # garantees and support are strongly adviced to contract a Free Software # Service Company # # 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 2 # 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, write to the Free Software # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. # ############################################################################## from AccessControl import ClassSecurityInfo, Unauthorized from Products.ERP5Type.Globals import InitializeClass from Products.ERP5Type import Permissions from OFS.Image import Pdata from cStringIO import StringIO from Products.ERP5Type.TransactionalVariable import getTransactionalVariable _MARKER = [] LOCK_PERMISSION_KEY = 'TRANSACTIONAL_VARIABLE_FORMAT_PERMISSION_LOCK_FLAG' class DocumentMixin: """ Implementation of IDocument interface convert must not be overloaded as it checks conversion format permission isSupportBaseDataConversion can be overriden, if base_conversion is supported (eg. OOoDocuments, TextDocument). """ security = ClassSecurityInfo() security.declareProtected(Permissions.AccessContentsInformation, 'convert') def convert(self, format, **kw): """ Main content conversion function, returns result which should be returned and stored in cache. If format is not allowed for download, Unauthorized exception is raised. format - the format specied in the form of an extension string (ex. jpeg, html, text, txt, etc.) **kw can be various things - e.g. resolution """ transaction_variable = getTransactionalVariable() if LOCK_PERMISSION_KEY in transaction_variable: # in convert we want always to check conversion format permission # to bypass such check one should use _convert directly del transaction_variable[LOCK_PERMISSION_KEY] self._checkConversionFormatPermission(format, lock_checking=True, **kw) pre_converted_only = kw.pop('pre_converted_only', False) if pre_converted_only: # we will use ONLY cache to return converted content # if respective document is not in cache we will return a good default content try: kw['format'] = format result = self.getConversion(**kw) except KeyError: # respective document is not cached yet and we should return a failure safe content instead result = self.getFailsafeConversion(**kw) else: # generate conversion on the fly or get it from cache (if already stored) result = self._convert(format, **kw) if LOCK_PERMISSION_KEY in transaction_variable: del transaction_variable[LOCK_PERMISSION_KEY] return result security.declareProtected(Permissions.AccessContentsInformation, 'getFailsafeConversion') def getFailsafeConversion(self, **kw): """ Return a failure resistent conversion of a document """ method = self._getTypeBasedMethod('getFailsafeConversion', fallback_script_id='Document_getFailsafeConversion') return method(**kw) def _convert(self, format, **kw): """Private method which make the transformation. Must be overriden !!! """ raise NotImplementedError security.declareProtected(Permissions.AccessContentsInformation, 'checkConversionFormatPermission') def checkConversionFormatPermission(self, format, **kw): """Public version of _checkConversionFormatPermission Without raising return just True or False. """ try: self._checkConversionFormatPermission(format, **kw) except Unauthorized: return False else: return True def _checkConversionFormatPermission(self, format, lock_checking=False, **kw): """Private method to check permission when access specified format. This method raises """ transaction_variable = getTransactionalVariable() if transaction_variable.get(LOCK_PERMISSION_KEY, False): # Permission already checked in convert with final format, # do not check permission for intermediate formats return True # XXX cache result in TV method = self._getTypeBasedMethod('checkConversionFormatPermission', fallback_script_id='Document_checkConversionFormatPermission') if '**' not in method.params(): # Backward compatibility code: # Existing Type Based Method doesn't support new **kw argument # in their signature. is_allowed = method(format=format) else: is_allowed = method(format=format, **kw) if not is_allowed: raise Unauthorized('Document: user does not have enough permission'\ ' to access document in %s format' %\ (format or 'original')) transaction_variable[LOCK_PERMISSION_KEY] = lock_checking security.declareProtected(Permissions.AccessContentsInformation, 'isSupportBaseDataConversion') def isSupportBaseDataConversion(self): """Tell if document implement IBaseConvertable Interface. By default it doens't """ return False InitializeClass(DocumentMixin)