# copyright 2003-2010 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/>.
"""Helper classes to execute RQL queries on a set of sources, performing
security checking and data aggregation.
"""
from __future__ import with_statement
__docformat__ = "restructuredtext en"
from itertools import repeat
from logilab.common.cache import Cache
from logilab.common.compat import any
from rql import RQLSyntaxError
from rql.stmts import Union, Select
from rql.nodes import (Relation, VariableRef, Constant, SubQuery, Function,
Exists, Not)
from cubicweb import Unauthorized, QueryError, UnknownEid, typed_eid
from cubicweb import server
from cubicweb.rset import ResultSet
from cubicweb.server.utils import cleanup_solutions
from cubicweb.server.rqlannotation import SQLGenAnnotator, set_qdata
from cubicweb.server.ssplanner import READ_ONLY_RTYPES, add_types_restriction
from cubicweb.server.session import security_enabled
def empty_rset(rql, args, rqlst=None):
"""build an empty result set object"""
return ResultSet([], rql, args, rqlst=rqlst)
def update_varmap(varmap, selected, table):
"""return a sql schema to store RQL query result"""
for i, term in enumerate(selected):
key = term.as_string()
value = '%s.C%s' % (table, i)
if varmap.get(key, value) != value:
raise Exception('variable name conflict on %s: got %s / %s'
% (key, value, varmap))
varmap[key] = value
# permission utilities ########################################################
def check_no_password_selected(rqlst):
"""check that Password entities are not selected"""
for solution in rqlst.solutions:
if 'Password' in solution.itervalues():
raise Unauthorized('Password selection is not allowed')
def term_etype(session, term, solution, args):
"""return the entity type for the given term (a VariableRef or a Constant
node)
"""
try:
return solution[term.name]
except AttributeError:
return session.describe(term.eval(args))[0]
def check_read_access(session, rqlst, solution, args):
"""check that the given user has credentials to access data read the
query
return a dict defining necessary local checks (due to use of rql expression
in the schema), keys are variable names and values associated rql expression
for the associated variable with the given solution
"""
# use `term_etype` since we've to deal with rewritten constants here,
# when used as an external source by another repository.
# XXX what about local read security w/ those rewritten constants...
schema = session.repo.schema
if rqlst.where is not None:
for rel in rqlst.where.iget_nodes(Relation):
# XXX has_text may have specific perm ?
if rel.r_type in READ_ONLY_RTYPES:
continue
rschema = schema.rschema(rel.r_type)
if rschema.final:
eschema = schema.eschema(term_etype(session, rel.children[0],
solution, args))
rdef = eschema.rdef(rschema)
else:
rdef = rschema.rdef(term_etype(session, rel.children[0],
solution, args),
term_etype(session, rel.children[1].children[0],
solution, args))
if not session.user.matching_groups(rdef.get_groups('read')):
# XXX rqlexpr not allowed
raise Unauthorized('read', rel.r_type)
localchecks = {}
# iterate on defined_vars and not on solutions to ignore column aliases
for varname in rqlst.defined_vars:
eschema = schema.eschema(solution[varname])
if eschema.final:
continue
if not session.user.matching_groups(eschema.get_groups('read')):
erqlexprs = eschema.get_rqlexprs('read')
if not erqlexprs:
ex = Unauthorized('read', solution[varname])
ex.var = varname
raise ex
# don't insert security on variable only referenced by 'NOT X relation Y' or
# 'NOT EXISTS(X relation Y)'
varinfo = rqlst.defined_vars[varname].stinfo
if varinfo['selected'] or (
len([r for r in varinfo['relations']
if (not schema.rschema(r.r_type).final
and ((isinstance(r.parent, Exists) and r.parent.neged(strict=True))
or isinstance(r.parent, Not)))])
!= len(varinfo['relations'])):
localchecks[varname] = erqlexprs
return localchecks
def add_noinvariant(noinvariant, restricted, select, nbtrees):
# a variable can actually be invariant if it has not been restricted for
# security reason or if security assertion hasn't modified the possible
# solutions for the query
if nbtrees != 1:
for vname in restricted:
try:
noinvariant.add(select.defined_vars[vname])
except KeyError:
# this is an alias
continue
else:
for vname in restricted:
try:
var = select.defined_vars[vname]
except KeyError:
# this is an alias
continue
if len(var.stinfo['possibletypes']) != 1:
noinvariant.add(var)
def _expand_selection(terms, selected, aliases, select, newselect):
for term in terms:
for vref in term.iget_nodes(VariableRef):
if not vref.name in selected:
select.append_selected(vref)
colalias = newselect.get_variable(vref.name, len(aliases))
aliases.append(VariableRef(colalias))
selected.add(vref.name)
# Plans #######################################################################
class ExecutionPlan(object):
"""the execution model of a rql query, composed of querier steps"""
def __init__(self, querier, rqlst, args, session):
# original rql syntax tree
self.rqlst = rqlst
self.args = args or {}
# session executing the query
self.session = session
# quick reference to the system source
self.syssource = session.pool.source('system')
# execution steps
self.steps = []
# index of temporary tables created during execution
self.temp_tables = {}
# various resource accesors
self.querier = querier
self.schema = querier.schema
self.sqlannotate = querier.sqlgen_annotate
self.rqlhelper = session.vreg.rqlhelper
def annotate_rqlst(self):
if not self.rqlst.annotated:
self.rqlhelper.annotate(self.rqlst)
def add_step(self, step):
"""add a step to the plan"""
self.steps.append(step)
def clean(self):
"""remove temporary tables"""
self.syssource.clean_temp_data(self.session, self.temp_tables)
def sqlexec(self, sql, args=None):
return self.syssource.sqlexec(self.session, sql, args)
def execute(self):
"""execute a plan and return resulting rows"""
try:
for step in self.steps:
result = step.execute()
# the latest executed step contains the full query result
return result
finally:
self.clean()
def make_temp_table_name(self, table):
"""
return a temp table name according to db backend
"""
return self.syssource.make_temp_table_name(table)
def init_temp_table(self, table, selected, sol):
"""initialize sql schema and variable map for a temporary table which
will be used to store result for the given rqlst
"""
try:
outputmap, sqlschema, _ = self.temp_tables[table]
update_varmap(outputmap, selected, table)
except KeyError:
sqlschema, outputmap = self.syssource.temp_table_def(selected, sol,
table)
self.temp_tables[table] = [outputmap, sqlschema, False]
return outputmap
def create_temp_table(self, table):
"""create a temporary table to store result for the given rqlst"""
if not self.temp_tables[table][-1]:
sqlschema = self.temp_tables[table][1]
self.syssource.create_temp_table(self.session, table, sqlschema)
self.temp_tables[table][-1] = True
def preprocess(self, union, security=True):
"""insert security when necessary then annotate rql st for sql generation
return rqlst to actually execute
"""
cached = None
if security and self.session.read_security:
# ensure security is turned of when security is inserted,
# else we may loop for ever...
if self.session.transaction_data.get('security-rqlst-cache'):
key = self.cache_key
else:
key = None
if key is not None and key in self.session.transaction_data:
cachedunion, args = self.session.transaction_data[key]
union.children[:] = []
for select in cachedunion.children:
union.append(select)
union.has_text_query = cachedunion.has_text_query
args.update(self.args)
self.args = args
cached = True
else:
noinvariant = set()
with security_enabled(self.session, read=False):
self._insert_security(union, noinvariant)
if key is not None:
self.session.transaction_data[key] = (union, self.args)
else:
noinvariant = ()
if cached is None:
self.rqlhelper.simplify(union)
self.sqlannotate(union)
set_qdata(self.schema.rschema, union, noinvariant)
if union.has_text_query:
self.cache_key = None
def _insert_security(self, union, noinvariant):
for select in union.children[:]:
for subquery in select.with_:
self._insert_security(subquery.query, noinvariant)
localchecks, restricted = self._check_permissions(select)
if any(localchecks):
rewrite = self.session.rql_rewriter.rewrite
nbtrees = len(localchecks)
myunion = union
# transform in subquery when len(localchecks)>1 and groups
if nbtrees > 1 and (select.orderby or select.groupby or
select.having or select.has_aggregat or
select.distinct or
select.limit or select.offset):
newselect = Select()
# only select variables in subqueries
origselection = select.selection
select.select_only_variables()
select.has_aggregat = False
# create subquery first so correct node are used on copy
# (eg ColumnAlias instead of Variable)
aliases = [VariableRef(newselect.get_variable(vref.name, i))
for i, vref in enumerate(select.selection)]
selected = set(vref.name for vref in aliases)
# now copy original selection and groups
for term in origselection:
newselect.append_selected(term.copy(newselect))
if select.orderby:
sortterms = []
for sortterm in select.orderby:
sortterms.append(sortterm.copy(newselect))
for fnode in sortterm.get_nodes(Function):
if fnode.name == 'FTIRANK':
# we've to fetch the has_text relation as well
var = fnode.children[0].variable
rel = iter(var.stinfo['ftirels']).next()
assert not rel.ored(), 'unsupported'
newselect.add_restriction(rel.copy(newselect))
# remove relation from the orig select and
# cleanup variable stinfo
rel.parent.remove(rel)
var.stinfo['ftirels'].remove(rel)
var.stinfo['relations'].remove(rel)
# XXX not properly re-annotated after security insertion?
newvar = newselect.get_variable(var.name)
newvar.stinfo.setdefault('ftirels', set()).add(rel)
newvar.stinfo.setdefault('relations', set()).add(rel)
newselect.set_orderby(sortterms)
_expand_selection(select.orderby, selected, aliases, select, newselect)
select.orderby = () # XXX dereference?
if select.groupby:
newselect.set_groupby([g.copy(newselect) for g in select.groupby])
_expand_selection(select.groupby, selected, aliases, select, newselect)
select.groupby = () # XXX dereference?
if select.having:
newselect.set_having([g.copy(newselect) for g in select.having])
_expand_selection(select.having, selected, aliases, select, newselect)
select.having = () # XXX dereference?
if select.limit:
newselect.limit = select.limit
select.limit = None
if select.offset:
newselect.offset = select.offset
select.offset = 0
myunion = Union()
newselect.set_with([SubQuery(aliases, myunion)], check=False)
newselect.distinct = select.distinct
solutions = [sol.copy() for sol in select.solutions]
cleanup_solutions(newselect, solutions)
newselect.set_possible_types(solutions)
# if some solutions doesn't need rewriting, insert original
# select as first union subquery
if () in localchecks:
myunion.append(select)
# we're done, replace original select by the new select with
# subqueries (more added in the loop below)
union.replace(select, newselect)
elif not () in localchecks:
union.remove(select)
for lcheckdef, lchecksolutions in localchecks.iteritems():
if not lcheckdef:
continue
myrqlst = select.copy(solutions=lchecksolutions)
myunion.append(myrqlst)
# in-place rewrite + annotation / simplification
lcheckdef = [((var, 'X'), rqlexprs) for var, rqlexprs in lcheckdef]
rewrite(myrqlst, lcheckdef, lchecksolutions, self.args)
add_noinvariant(noinvariant, restricted, myrqlst, nbtrees)
if () in localchecks:
select.set_possible_types(localchecks[()])
add_types_restriction(self.schema, select)
add_noinvariant(noinvariant, restricted, select, nbtrees)
self.rqlhelper.annotate(union)
def _check_permissions(self, rqlst):
"""return a dict defining "local checks", e.g. RQLExpression defined in
the schema that should be inserted in the original query
solutions where a variable has a type which the user can't definitly read
are removed, else if the user may read it (eg if an rql expression is
defined for the "read" permission of the related type), the local checks
dict for the solution is updated
return a dict with entries for each different local check necessary,
with associated solutions as value. A local check is defined by a list
of 2-uple, with variable name as first item and the necessary rql
expression as second item for each variable which has to be checked.
So solutions which don't require local checks will be associated to
the empty tuple key.
note: rqlst should not have been simplified at this point
"""
session = self.session
msgs = []
neweids = session.transaction_data.get('neweids', ())
varkwargs = {}
if not session.transaction_data.get('security-rqlst-cache'):
for var in rqlst.defined_vars.itervalues():
if var.stinfo['constnode'] is not None:
eid = var.stinfo['constnode'].eval(self.args)
varkwargs[var.name] = typed_eid(eid)
# dictionnary of variables restricted for security reason
localchecks = {}
restricted_vars = set()
newsolutions = []
for solution in rqlst.solutions:
try:
localcheck = check_read_access(session, rqlst, solution, self.args)
except Unauthorized, ex:
msg = 'remove %s from solutions since %s has no %s access to %s'
msg %= (solution, session.user.login, ex.args[0], ex.args[1])
msgs.append(msg)
LOGGER.info(msg)
else:
newsolutions.append(solution)
# try to benefit of rqlexpr.check cache for entities which
# are specified by eid in query'args
for varname, eid in varkwargs.iteritems():
try:
rqlexprs = localcheck.pop(varname)
except KeyError:
continue
if eid in neweids:
continue
for rqlexpr in rqlexprs:
if rqlexpr.check(session, eid):
break
else:
raise Unauthorized()
restricted_vars.update(localcheck)
localchecks.setdefault(tuple(localcheck.iteritems()), []).append(solution)
# raise Unautorized exception if the user can't access to any solution
if not newsolutions:
raise Unauthorized('\n'.join(msgs))
rqlst.set_possible_types(newsolutions)
return localchecks, restricted_vars
def finalize(self, select, solutions, insertedvars):
rqlst = Union()
rqlst.append(select)
for mainvarname, rschema, newvarname in insertedvars:
nvartype = str(rschema.objects(solutions[0][mainvarname])[0])
for sol in solutions:
sol[newvarname] = nvartype
select.clean_solutions(solutions)
self.rqlhelper.annotate(rqlst)
self.preprocess(rqlst, security=False)
return rqlst
class InsertPlan(ExecutionPlan):
"""an execution model specific to the INSERT rql query
"""
def __init__(self, querier, rqlst, args, session):
ExecutionPlan.__init__(self, querier, rqlst, args, session)
# save originaly selected variable, we may modify this
# dictionary for substitution (query parameters)
self.selected = rqlst.selection
# list of new or updated entities definition (utils.Entity)
self.e_defs = [[]]
# list of new relation definition (3-uple (from_eid, r_type, to_eid)
self.r_defs = set()
# indexes to track entity definitions bound to relation definitions
self._r_subj_index = {}
self._r_obj_index = {}
self._expanded_r_defs = {}
def add_entity_def(self, edef):
"""add an entity definition to build"""
edef.querier_pending_relations = {}
self.e_defs[-1].append(edef)
def add_relation_def(self, rdef):
"""add an relation definition to build"""
self.r_defs.add(rdef)
if not isinstance(rdef[0], int):
self._r_subj_index.setdefault(rdef[0], []).append(rdef)
if not isinstance(rdef[2], int):
self._r_obj_index.setdefault(rdef[2], []).append(rdef)
def substitute_entity_def(self, edef, edefs):
"""substitute an incomplete entity definition by a list of complete
equivalents
e.g. on queries such as ::
INSERT Personne X, Societe Y: X nom N, Y nom 'toto', X travaille Y
WHERE U login 'admin', U login N
X will be inserted as many times as U exists, and so the X travaille Y
relations as to be added as many time as X is inserted
"""
if not edefs or not self.e_defs:
# no result, no entity will be created
self.e_defs = ()
return
# first remove the incomplete entity definition
colidx = self.e_defs[0].index(edef)
for i, row in enumerate(self.e_defs[:]):
self.e_defs[i][colidx] = edefs[0]
samplerow = self.e_defs[i]
for edef_ in edefs[1:]:
row = samplerow[:]
row[colidx] = edef_
self.e_defs.append(row)
# now, see if this entity def is referenced as subject in some relation
# definition
if self._r_subj_index.has_key(edef):
for rdef in self._r_subj_index[edef]:
expanded = self._expanded(rdef)
result = []
for exp_rdef in expanded:
for edef_ in edefs:
result.append( (edef_, exp_rdef[1], exp_rdef[2]) )
self._expanded_r_defs[rdef] = result
# and finally, see if this entity def is referenced as object in some
# relation definition
if self._r_obj_index.has_key(edef):
for rdef in self._r_obj_index[edef]:
expanded = self._expanded(rdef)
result = []
for exp_rdef in expanded:
for edef_ in edefs:
result.append( (exp_rdef[0], exp_rdef[1], edef_) )
self._expanded_r_defs[rdef] = result
def _expanded(self, rdef):
"""return expanded value for the given relation definition"""
try:
return self._expanded_r_defs[rdef]
except KeyError:
self.r_defs.remove(rdef)
return [rdef]
def relation_defs(self):
"""return the list for relation definitions to insert"""
for rdefs in self._expanded_r_defs.values():
for rdef in rdefs:
yield rdef
for rdef in self.r_defs:
yield rdef
def insert_entity_defs(self):
"""return eids of inserted entities in a suitable form for the resulting
result set, e.g.:
e.g. on queries such as ::
INSERT Personne X, Societe Y: X nom N, Y nom 'toto', X travaille Y
WHERE U login 'admin', U login N
if there is two entities matching U, the result set will look like
[(eidX1, eidY1), (eidX2, eidY2)]
"""
session = self.session
repo = session.repo
results = []
for row in self.e_defs:
results.append([repo.glob_add_entity(session, edef)
for edef in row])
return results
def insert_relation_defs(self):
session = self.session
repo = session.repo
for subj, rtype, obj in self.relation_defs():
# if a string is given into args instead of an int, we get it here
if isinstance(subj, basestring):
subj = typed_eid(subj)
elif not isinstance(subj, (int, long)):
subj = subj.eid
if isinstance(obj, basestring):
obj = typed_eid(obj)
elif not isinstance(obj, (int, long)):
obj = obj.eid
if repo.schema.rschema(rtype).inlined:
entity = session.entity_from_eid(subj)
entity[rtype] = obj
repo.glob_update_entity(session, entity, set((rtype,)))
else:
repo.glob_add_relation(session, subj, rtype, obj)
class QuerierHelper(object):
"""helper class to execute rql queries, putting all things together"""
def __init__(self, repo, schema):
# system info helper
self._repo = repo
# instance schema
self.set_schema(schema)
def set_schema(self, schema):
self.schema = schema
repo = self._repo
# rql st and solution cache. Don't bother using a Cache instance: we
# should have a limited number of queries in there, since there are no
# entries in this cache for user queries (which have no args)
self._rql_cache = {}
# rql cache key cache
self._rql_ck_cache = Cache(repo.config['rql-cache-size'])
# some cache usage stats
self.cache_hit, self.cache_miss = 0, 0
# rql parsing / analysing helper
self.solutions = repo.vreg.solutions
rqlhelper = repo.vreg.rqlhelper
# set backend on the rql helper, will be used for function checking
rqlhelper.backend = repo.config.sources()['system']['db-driver']
self._parse = rqlhelper.parse
self._annotate = rqlhelper.annotate
# rql planner
# note: don't use repo.sources, may not be built yet, and also "admin"
# isn't an actual source
if len([uri for uri in repo.config.sources() if uri != 'admin']) < 2:
from cubicweb.server.ssplanner import SSPlanner
self._planner = SSPlanner(schema, rqlhelper)
else:
from cubicweb.server.msplanner import MSPlanner
self._planner = MSPlanner(schema, rqlhelper)
# sql generation annotator
self.sqlgen_annotate = SQLGenAnnotator(schema).annotate
def parse(self, rql, annotate=False):
"""return a rql syntax tree for the given rql"""
try:
return self._parse(unicode(rql), annotate=annotate)
except UnicodeError:
raise RQLSyntaxError(rql)
def plan_factory(self, rqlst, args, session):
"""create an execution plan for an INSERT RQL query"""
if rqlst.TYPE == 'insert':
return InsertPlan(self, rqlst, args, session)
return ExecutionPlan(self, rqlst, args, session)
def execute(self, session, rql, args=None, build_descr=True):
"""execute a rql query, return resulting rows and their description in
a `ResultSet` object
* `rql` should be an Unicode string or a plain ASCII string
* `args` the optional parameters dictionary associated to the query
* `build_descr` is a boolean flag indicating if the description should
be built on select queries (if false, the description will be en empty
list)
on INSERT queries, there will be one row with the eid of each inserted
entity
result for DELETE and SET queries is undefined yet
to maximize the rql parsing/analyzing cache performance, you should
always use substitute arguments in queries (i.e. avoid query such as
'Any X WHERE X eid 123'!)
"""
if server.DEBUG & (server.DBG_RQL | server.DBG_SQL):
if server.DEBUG & (server.DBG_MORE | server.DBG_SQL):
print '*'*80
print 'querier input', rql, args
# parse the query and binds variables
try:
cachekey = rql
if args:
eidkeys = self._rql_ck_cache[rql]
if eidkeys:
try:
cachekey = self._repo.querier_cache_key(session, rql,
args, eidkeys)
except UnknownEid:
# we want queries such as "Any X WHERE X eid 9999"
# return an empty result instead of raising UnknownEid
return empty_rset(rql, args)
rqlst = self._rql_cache[cachekey]
self.cache_hit += 1
except KeyError:
self.cache_miss += 1
rqlst = self.parse(rql)
try:
eidkeys = self.solutions(session, rqlst, args)
except UnknownEid:
# we want queries such as "Any X WHERE X eid 9999" return an
# empty result instead of raising UnknownEid
return empty_rset(rql, args, rqlst)
self._rql_ck_cache[rql] = eidkeys
if eidkeys:
cachekey = self._repo.querier_cache_key(session, rql, args,
eidkeys)
self._rql_cache[cachekey] = rqlst
orig_rqlst = rqlst
if rqlst.TYPE != 'select':
if session.read_security:
check_no_password_selected(rqlst)
# write query, ensure session's mode is 'write' so connections won't
# be released until commit/rollback
session.mode = 'write'
cachekey = None
else:
if session.read_security:
for select in rqlst.children:
check_no_password_selected(select)
# on select query, always copy the cached rqlst so we don't have to
# bother modifying it. This is not necessary on write queries since
# a new syntax tree is built from them.
rqlst = rqlst.copy()
self._annotate(rqlst)
# make an execution plan
plan = self.plan_factory(rqlst, args, session)
plan.cache_key = cachekey
self._planner.build_plan(plan)
# execute the plan
try:
results = plan.execute()
except Unauthorized:
# XXX this could be done in security's after_add_relation hooks
# since it's actually realy only needed there (other relations
# security is done *before* actual changes, and add/update entity
# security is done after changes but in an operation, and exception
# generated in operation's events properly generate a rollback on
# the session). Even though, this is done here for a better
# consistency: getting an Unauthorized exception means the
# transaction has been rollbacked
#
# notes:
# * we should not reset the pool here, since we don't want the
# session to loose its pool during processing
# * don't rollback if we're in the commit process, will be handled
# by the session
if session.commit_state is None:
session.rollback(reset_pool=False)
raise
# build a description for the results if necessary
descr = ()
if build_descr:
if rqlst.TYPE == 'select':
# sample selection
descr = session.build_description(orig_rqlst, args, results)
elif rqlst.TYPE == 'insert':
# on insert plan, some entities may have been auto-casted,
# so compute description manually even if there is only
# one solution
basedescr = [None] * len(plan.selected)
todetermine = zip(xrange(len(plan.selected)), repeat(False))
descr = session._build_descr(results, basedescr, todetermine)
# FIXME: get number of affected entities / relations on non
# selection queries ?
# return a result set object
return ResultSet(results, rql, args, descr, orig_rqlst)
from logging import getLogger
from cubicweb import set_log_methods
LOGGER = getLogger('cubicweb.querier')
set_log_methods(QuerierHelper, LOGGER)