"""Helper classes to execute RQL queries on a set of sources, performing
security checking and data aggregation.
:organization: Logilab
:copyright: 2001-2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
"""
__docformat__ = "restructuredtext en"
from itertools import repeat
from logilab.common.cache import Cache
from logilab.common.compat import any
from rql import RQLHelper, RQLSyntaxError
from rql.stmts import Union, Select
from rql.nodes import (Relation, VariableRef, Constant, Exists, Variable,
SubQuery)
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 add_types_restriction
def empty_rset(session, 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' % key)
varmap[key] = value
# permission utilities ########################################################
def var_kwargs(restriction, args):
varkwargs = {}
for rel in restriction.iget_nodes(Relation):
cmp = rel.children[1]
if rel.r_type == 'eid' and cmp.operator == '=' and \
isinstance(cmp.children[0], Constant) and \
cmp.children[0].type == 'Substitute':
varkwargs[rel.children[0].name] = typed_eid(cmp.children[0].eval(args))
return varkwargs
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 check_read_access(schema, user, rqlst, solution):
"""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
"""
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 ('is', 'is_instance_of', 'has_text', 'identity', 'eid'):
continue
if not schema.rschema(rel.r_type).has_access(user, 'read'):
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:
etype = solution[varname]
eschema = schema.eschema(etype)
if not eschema.has_access(user, 'read'):
erqlexprs = eschema.get_rqlexprs('read')
if not erqlexprs:
ex = Unauthorized('read', etype)
ex.var = varname
raise ex
#assert len(erqlexprs) == 1
localchecks[varname] = tuple(erqlexprs)
return localchecks
def noinvariant_vars(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:
yield 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:
yield 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.rqlhelper = querier._rqlhelper
self.sqlannotate = querier.sqlgen_annotate
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 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
"""
#if server.DEBUG:
# print '------- preprocessing', union.as_string('utf8')
noinvariant = set()
if security and not self.session.is_super_session:
self._insert_security(union, noinvariant)
self.rqlhelper.simplify(union)
self.sqlannotate(union)
set_qdata(union, noinvariant)
if union.has_text_query:
self.cache_key = None
def _insert_security(self, union, noinvariant):
rh = self.rqlhelper
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.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:
newselect.set_orderby([s.copy(newselect) for s in select.orderby])
_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)
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
rewrite(myrqlst, lcheckdef, lchecksolutions, self.args)
noinvariant.update(noinvariant_vars(restricted, myrqlst, nbtrees))
if () in localchecks:
select.set_possible_types(localchecks[()])
add_types_restriction(self.schema, select)
noinvariant.update(noinvariant_vars(restricted, select, nbtrees))
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
"""
assert not self.session.is_super_session
user = self.session.user
schema = self.schema
msgs = []
# dictionnary of variables restricted for security reason
localchecks = {}
if rqlst.where is not None:
varkwargs = var_kwargs(rqlst.where, self.args)
neweids = self.session.query_data('neweids', ())
else:
varkwargs = None
restricted_vars = set()
newsolutions = []
for solution in rqlst.solutions:
try:
localcheck = check_read_access(schema, user, rqlst, solution)
except Unauthorized, ex:
msg = 'remove %s from solutions since %s has no %s access to %s'
msg %= (solution, user.login, ex.args[0], ex.args[1])
msgs.append(msg)
LOGGER.info(msg)
else:
newsolutions.append(solution)
if varkwargs:
# 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(self.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 = []
# indexes to track entity definitions bound to relation definitions
self._r_subj_index = {}
self._r_obj_index = {}
self._expanded_r_defs = {}
def relation_definitions(self, rqlst, to_build):
"""add constant values to entity def, mark variables to be selected
"""
to_select = {}
for relation in rqlst.main_relations:
lhs, rhs = relation.get_variable_parts()
rtype = relation.r_type
if rtype in ('eid', 'has_text', 'is', 'is_instance_of', 'identity'):
raise QueryError("can't assign to %s" % rtype)
try:
edef = to_build[str(lhs)]
except KeyError:
# lhs var is not to build, should be selected and added as an
# object relation
edef = to_build[str(rhs)]
to_select.setdefault(edef, []).append((rtype, lhs, 1))
else:
if isinstance(rhs, Constant) and not rhs.uid:
# add constant values to entity def
value = rhs.eval(self.args)
eschema = edef.e_schema
attrtype = eschema.subject_relation(rtype).objects(eschema)[0]
if attrtype == 'Password' and isinstance(value, unicode):
value = value.encode('UTF8')
edef[rtype] = value
elif to_build.has_key(str(rhs)):
# create a relation between two newly created variables
self.add_relation_def((edef, rtype, to_build[rhs.name]))
else:
to_select.setdefault(edef, []).append( (rtype, rhs, 0) )
return to_select
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.append(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.eid_rset(subj).get_entity(0, 0)
entity[rtype] = obj
repo.glob_update_entity(session, entity)
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
# application schema
self.set_schema(schema)
def set_schema(self, schema):
self.schema = schema
# rql parsing / analysing helper
self._rqlhelper = RQLHelper(schema, special_relations={'eid': 'uid',
'has_text': 'fti'})
self._rql_cache = Cache(self._repo.config['rql-cache-size'])
self.cache_hit, self.cache_miss = 0, 0
# 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 self._repo.config.sources() if uri != 'admin']) < 2:
from cubicweb.server.ssplanner import SSPlanner
self._planner = SSPlanner(schema, self._rqlhelper)
else:
from cubicweb.server.msplanner import MSPlanner
self._planner = MSPlanner(schema, self._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._rqlhelper.parse(unicode(rql), annotate=annotate)
except UnicodeError:
raise RQLSyntaxError(rql)
def solutions(self, session, rqlst, args):
assert session is not None
def type_from_eid(eid, type_from_eid=self._repo.type_from_eid,
session=session):
return type_from_eid(eid, session)
self._rqlhelper.compute_solutions(rqlst, {'eid': type_from_eid}, args)
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, eid_key=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)
* `eid_key` must be both a key in args and a substitution in the rql
query. It should be used to enhance cacheability of rql queries.
It may be a tuple for keys in args.
eid_key must be providen in case where a eid substitution is providen
and resolve some ambiguity in the possible solutions infered for each
variable in the query.
on INSERT queries, there will be on 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 (eg avoid query such as
'Any X WHERE X eid 123'!)
"""
if server.DEBUG:
print '*'*80
print rql
# parse the query and binds variables
if eid_key is not None:
if not isinstance(eid_key, (tuple, list)):
eid_key = (eid_key,)
cachekey = [rql]
for key in eid_key:
try:
etype = self._repo.type_from_eid(args[key], session)
except KeyError:
raise QueryError('bad cache key %s (no value)' % key)
except TypeError:
raise QueryError('bad cache key %s (value: %r)' % (key, args[key]))
except UnknownEid:
# we want queries such as "Any X WHERE X eid 9999"
# return an empty result instead of raising UnknownEid
return empty_rset(session, rql, args)
cachekey.append(etype)
cachekey = tuple(cachekey)
else:
cachekey = rql
try:
rqlst = self._rql_cache[cachekey]
self.cache_hit += 1
except KeyError:
self.cache_miss += 1
rqlst = self.parse(rql)
try:
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(session, rql, args, rqlst)
self._rql_cache[cachekey] = rqlst
orig_rqlst = rqlst
if not rqlst.TYPE == 'select':
if not session.is_super_session:
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 not session.is_super_session:
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._rqlhelper.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
session.rollback()
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, eid_key, orig_rqlst)
from logging import getLogger
from cubicweb import set_log_methods
LOGGER = getLogger('cubicweb.querier')
set_log_methods(QuerierHelper, LOGGER)