add a new method iter_process_result which does the same as proces_result but is a generator (closes #1625374)
process_result is reimplemented using the new method, and the two helper
methods are turned into generators.
These generators use cursor.fetchmany instead of cursor.fetchall after setting
cursor.arraysize to 100. This means that the whole result set should never
loaded in memory when using the iter_process_result method. This is used in the
"portable" database dump implementation when we typically to 'SELECT * FROM
table', but could probably be used too in other parts of cubicweb.
# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr## This file is part of CubicWeb.## CubicWeb is free software: you can redistribute it and/or modify it under the# terms of the GNU Lesser General Public License as published by the Free# Software Foundation, either version 2.1 of the License, or (at your option)# any later version.## CubicWeb 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 Lesser General Public License for more# details.## You should have received a copy of the GNU Lesser General Public License along# with CubicWeb. If not, see <http://www.gnu.org/licenses/>."""SQL utilities functions and classes."""__docformat__="restructuredtext en"importosimportsubprocessfromdatetimeimportdatetime,datefromlogilabimportdatabaseasdb,commonaslgcfromlogilab.common.shellutilsimportProgressBarfromlogilab.common.dateimporttodate,todatetime,utcdatetime,utctimefromlogilab.database.sqlgenimportSQLGeneratorfromcubicwebimportBinary,ConfigurationErrorfromcubicweb.uilibimportremove_html_tagsfromcubicweb.schemaimportPURE_VIRTUAL_RTYPESfromcubicweb.serverimportSQL_CONNECT_HOOKSfromcubicweb.server.utilsimportcrypt_passwordfromrql.utilsimportRQL_FUNCTIONS_REGISTRYlgc.USE_MX_DATETIME=FalseSQL_PREFIX='cw_'def_run_command(cmd):"""backup/restore command are string w/ lgc < 0.47, lists with earlier versions """ifisinstance(cmd,basestring):print'->',cmdreturnsubprocess.call(cmd,shell=True)print' '.join(cmd)returnsubprocess.call(cmd)defsqlexec(sqlstmts,cursor_or_execute,withpb=notos.environ.get('APYCOT_ROOT'),pbtitle='',delimiter=';'):"""execute sql statements ignoring DROP/ CREATE GROUP or USER statements error. If a cnx is given, commit at each statement """ifhasattr(cursor_or_execute,'execute'):execute=cursor_or_execute.executeelse:execute=cursor_or_executesqlstmts=sqlstmts.split(delimiter)ifwithpb:pb=ProgressBar(len(sqlstmts),title=pbtitle)forsqlinsqlstmts:sql=sql.strip()ifwithpb:pb.update()ifnotsql:continue# some dbapi modules doesn't accept unicode for sql stringexecute(str(sql))ifwithpb:printdefsqlgrants(schema,driver,user,text_index=True,set_owner=True,skip_relations=(),skip_entities=()):"""return sql to give all access privileges to the given user on the system schema """fromyams.schema2sqlimportgrant_schemafromcubicweb.server.sourcesimportnativeoutput=[]w=output.appendw(native.grant_schema(user,set_owner))w('')iftext_index:dbhelper=db.get_db_helper(driver)w(dbhelper.sql_grant_user_on_fti(user))w('')w(grant_schema(schema,user,set_owner,skip_entities=skip_entities,prefix=SQL_PREFIX))return'\n'.join(output)defsqlschema(schema,driver,text_index=True,user=None,set_owner=False,skip_relations=PURE_VIRTUAL_RTYPES,skip_entities=()):"""return the system sql schema, according to the given parameters"""fromyams.schema2sqlimportschema2sqlfromcubicweb.server.sourcesimportnativeifset_owner:assertuser,'user is argument required when set_owner is true'output=[]w=output.appendw(native.sql_schema(driver))w('')dbhelper=db.get_db_helper(driver)iftext_index:w(dbhelper.sql_init_fti().replace(';',';;'))w('')w(schema2sql(dbhelper,schema,prefix=SQL_PREFIX,skip_entities=skip_entities,skip_relations=skip_relations).replace(';',';;'))ifdbhelper.users_supportanduser:w('')w(sqlgrants(schema,driver,user,text_index,set_owner,skip_relations,skip_entities).replace(';',';;'))return'\n'.join(output)defsqldropschema(schema,driver,text_index=True,skip_relations=PURE_VIRTUAL_RTYPES,skip_entities=()):"""return the sql to drop the schema, according to the given parameters"""fromyams.schema2sqlimportdropschema2sqlfromcubicweb.server.sourcesimportnativeoutput=[]w=output.appendiftext_index:dbhelper=db.get_db_helper(driver)w(dbhelper.sql_drop_fti())w('')w(dropschema2sql(schema,prefix=SQL_PREFIX,skip_entities=skip_entities,skip_relations=skip_relations))w('')w(native.sql_drop_schema(driver))return'\n'.join(output)classSQLAdapterMixIn(object):"""Mixin for SQL data sources, getting a connection from a configuration dictionary and handling connection locking """def__init__(self,source_config):try:self.dbdriver=source_config['db-driver'].lower()dbname=source_config['db-name']exceptKeyError:raiseConfigurationError('missing some expected entries in sources file')dbhost=source_config.get('db-host')port=source_config.get('db-port')dbport=portandint(port)orNonedbuser=source_config.get('db-user')dbpassword=source_config.get('db-password')dbencoding=source_config.get('db-encoding','UTF-8')dbextraargs=source_config.get('db-extra-arguments')self.dbhelper=db.get_db_helper(self.dbdriver)self.dbhelper.record_connection_info(dbname,dbhost,dbport,dbuser,dbpassword,dbextraargs,dbencoding)self.sqlgen=SQLGenerator()# copy back some commonly accessed attributesdbapi_module=self.dbhelper.dbapi_moduleself.OperationalError=dbapi_module.OperationalErrorself.InterfaceError=dbapi_module.InterfaceErrorself.DbapiError=dbapi_module.Errorself._binary=self.dbhelper.binary_valueself._process_value=dbapi_module.process_valueself._dbencoding=dbencodingdefget_connection(self):"""open and return a connection to the database"""returnself.dbhelper.get_connection()defbackup_to_file(self,backupfile,confirm):forcmdinself.dbhelper.backup_commands(backupfile,keepownership=False):if_run_command(cmd):ifnotconfirm(' [Failed] Continue anyway?',default='n'):raiseException('Failed command: %s'%cmd)defrestore_from_file(self,backupfile,confirm,drop=True):forcmdinself.dbhelper.restore_commands(backupfile,keepownership=False,drop=drop):if_run_command(cmd):ifnotconfirm(' [Failed] Continue anyway?',default='n'):raiseException('Failed command: %s'%cmd)defmerge_args(self,args,query_args):ifargsisnotNone:newargs={}forkey,valinargs.iteritems():# convert cubicweb binary into db binaryifisinstance(val,Binary):val=self._binary(val.getvalue())newargs[key]=val# should not collidenewargs.update(query_args)returnnewargsreturnquery_argsdefprocess_result(self,cursor,column_callbacks=None,session=None):"""return a list of CubicWeb compliant values from data in the given cursor """returnlist(self.iter_process_result(cursor,column_callbacks,session))defiter_process_result(self,cursor,column_callbacks=None,session=None):"""return a iterator on tuples of CubicWeb compliant values from data in the given cursor """# use two different implementations to avoid paying the price of# callback lookup for each *cell* in results when there is nothing to# lookupifnotcolumn_callbacks:returnself._process_result(cursor)assertsessionreturnself._cb_process_result(cursor,column_callbacks,session)def_process_result(self,cursor):# begin bind to locals for optimizationdescr=cursor.descriptionencoding=self._dbencodingprocess_value=self._process_valuebinary=Binary# /endcursor.arraysize=100whileTrue:results=cursor.fetchmany()ifnotresults:breakforlineinresults:result=[]forcol,valueinenumerate(line):ifvalueisNone:result.append(value)continueresult.append(process_value(value,descr[col],encoding,binary))yieldresultdef_cb_process_result(self,cursor,column_callbacks,session):# begin bind to locals for optimizationdescr=cursor.descriptionencoding=self._dbencodingprocess_value=self._process_valuebinary=Binary# /endcursor.arraysize=100whileTrue:results=cursor.fetchmany()ifnotresults:breakforlineinresults:result=[]forcol,valueinenumerate(line):ifvalueisNone:result.append(value)continuecbstack=column_callbacks.get(col,None)ifcbstackisNone:value=process_value(value,descr[col],encoding,binary)else:forcbincbstack:value=cb(self,session,value)result.append(value)yieldresultdefpreprocess_entity(self,entity):"""return a dictionary to use as extra argument to cursor.execute to insert/update an entity into a SQL database """attrs={}eschema=entity.e_schemaforattr,valueinentity.cw_edited.iteritems():ifvalueisnotNoneandeschema.subjrels[attr].final:atype=str(entity.e_schema.destination(attr))ifatype=='Boolean':value=self.dbhelper.boolean_value(value)elifatype=='Password':# if value is a Binary instance, this mean we got it# from a query result and so it is already encryptedifisinstance(value,Binary):value=value.getvalue()else:value=crypt_password(value)value=self._binary(value)# XXX needed for sqlite but I don't think it is for other backends# Note: use is __class__ since issubclass(datetime, date)elifatypein('Datetime','TZDatetime')andtype(value)isdate:value=todatetime(value)elifatype=='Date'andisinstance(value,datetime):value=todate(value)elifatype=='TZDatetime'andgetattr(value,'tzinfo',None):value=utcdatetime(value)elifatype=='TZTime'andgetattr(value,'tzinfo',None):value=utctime(value)elifisinstance(value,Binary):value=self._binary(value.getvalue())attrs[SQL_PREFIX+str(attr)]=valueattrs[SQL_PREFIX+'eid']=entity.eidreturnattrs# these are overridden by set_log_methods below# only defining here to prevent pylint from complaininginfo=warning=error=critical=exception=debug=lambdamsg,*a,**kw:NonefromloggingimportgetLoggerfromcubicwebimportset_log_methodsset_log_methods(SQLAdapterMixIn,getLogger('cubicweb.sqladapter'))definit_sqlite_connexion(cnx):classgroup_concat(object):def__init__(self):self.values=[]defstep(self,value):ifvalueisnotNone:self.values.append(value)deffinalize(self):return', '.join(self.values)cnx.create_aggregate("GROUP_CONCAT",1,group_concat)def_limit_size(text,maxsize,format='text/plain'):iflen(text)<maxsize:returntextifformatin('text/html','text/xhtml','text/xml'):text=remove_html_tags(text)iflen(text)>maxsize:text=text[:maxsize]+'...'returntextdeflimit_size3(text,format,maxsize):return_limit_size(text,maxsize,format)cnx.create_function("LIMIT_SIZE",3,limit_size3)deflimit_size2(text,maxsize):return_limit_size(text,maxsize)cnx.create_function("TEXT_LIMIT_SIZE",2,limit_size2)importyams.constraintsyams.constraints.patch_sqlite_decimal()sqlite_hooks=SQL_CONNECT_HOOKS.setdefault('sqlite',[])sqlite_hooks.append(init_sqlite_connexion)definit_postgres_connexion(cnx):cnx.cursor().execute('SET TIME ZONE UTC')# commit is needed, else setting are lost if the connection is first# rollbackedcnx.commit()postgres_hooks=SQL_CONNECT_HOOKS.setdefault('postgres',[])postgres_hooks.append(init_postgres_connexion)