"""provide a minimal RQL support for google appengine dbmodel
:organization: Logilab
:copyright: 2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
"""
__docformat__ = "restructuredtext en"
from mx.DateTime import DateTimeType, DateTimeDeltaType
from datetime import datetime
from rql import RQLHelper, nodes
from logilab.common.compat import any
from cubicweb import Binary
from cubicweb.rset import ResultSet
from cubicweb.server import SQL_CONNECT_HOOKS
from google.appengine.api.datastore import Key, Get, Query, Entity
from google.appengine.api.datastore_types import Text, Blob
from google.appengine.api.datastore_errors import EntityNotFoundError, BadKeyError
def etype_from_key(key):
return Key(key).kind()
def poss_var_types(myvar, ovar, kind, solutions):
return frozenset(etypes[myvar] for etypes in solutions
if etypes[ovar] == kind)
def expand_result(results, result, myvar, values, dsget=None):
values = map(dsget, values)
if values:
result[myvar] = values.pop(0)
for value in values:
newresult = result.copy()
newresult[myvar] = value
results.append(newresult)
else:
results.remove(result)
def _resolve(restrictions, solutions, fixed):
varname = restrictions[0].searched_var
objs = []
for etype in frozenset(etypes[varname] for etypes in solutions):
gqlargs = {}
query = Query(etype)
for restriction in restrictions:
restriction.fill_query(fixed, query)
pobjs = query.Run()
if varname in fixed:
value = fixed[varname]
objs += (x for x in pobjs if x == value)
else:
objs += pobjs
if varname in fixed and not objs:
raise EidMismatch(varname, value)
return objs
def _resolve_not(restrictions, solutions, fixed):
restr = restrictions[0]
constrvarname = restr.constraint_var
if len(restrictions) > 1 or not constrvarname in fixed:
raise NotImplementedError()
varname = restr.searched_var
objs = []
for etype in frozenset(etypes[varname] for etypes in solutions):
gqlargs = {}
for operator in ('<', '>'):
query = Query(etype)
restr.fill_query(fixed, query, operator)
objs += query.Run()
return objs
def _print_results(rlist):
return '[%s]' % ', '.join(_print_result(r) for r in rlist)
def _print_result(rdict):
string = []
for k, v in rdict.iteritems():
if isinstance(v, Entity):
string.append('%s: %s' % (k, v.key()))#_print_result(v)))
elif isinstance(v, list):
string.append('%s: [%s]' % (k, ', '.join(str(i) for i in v)))
else:
string.append('%s: %s' % (k, v))
return '{%s}' % ', '.join(string)
class EidMismatch(Exception):
def __init__(self, varname, value):
self.varname = varname
self.value = value
class Restriction(object):
supported_operators = ('=',)
def __init__(self, rel):
operator = rel.children[1].operator
if not operator in self.supported_operators:
raise NotImplementedError('unsupported operator')
self.rel = rel
self.operator = operator
self.rtype = rel.r_type
self.var = rel.children[0]
def __repr__(self):
return '<%s for %s>' % (self.__class__.__name__, self.rel)
@property
def rhs(self):
return self.rel.children[1].children[0]
class MultipleRestriction(object):
def __init__(self, restrictions):
self.restrictions = restrictions
def resolve(self, solutions, fixed):
return _resolve(self.restrictions, solutions, fixed)
class VariableSelection(Restriction):
def __init__(self, rel, dsget, prefix='s'):
Restriction.__init__(self, rel)
self._dsget = dsget
self._not = self.rel.neged(strict=True)
self._prefix = prefix + '_'
def __repr__(self):
return '<%s%s for %s>' % (self._prefix[0], self.__class__.__name__, self.rel)
@property
def searched_var(self):
if self._prefix == 's_':
return self.var.name
return self.rhs.name
@property
def constraint_var(self):
if self._prefix == 's_':
return self.rhs.name
return self.var.name
def _possible_values(self, myvar, ovar, entity, solutions, dsprefix):
if self.rtype == 'identity':
return (entity.key(),)
value = entity.get(dsprefix + self.rtype)
if value is None:
return []
if not isinstance(value, list):
value = [value]
vartypes = poss_var_types(myvar, ovar, entity.kind(), solutions)
return (v for v in value if v.kind() in vartypes)
def complete_and_filter(self, solutions, results):
myvar = self.rhs.name
ovar = self.var.name
rtype = self.rtype
if self.schema.rschema(rtype).is_final():
# should be detected by rql.stcheck: "Any C WHERE NOT X attr C" doesn't make sense
#if self._not:
# raise NotImplementedError()
for result in results:
result[myvar] = result[ovar].get('s_'+rtype)
elif self.var.name in results[0]:
if self.rhs.name in results[0]:
self.filter(solutions, results)
else:
if self._not:
raise NotImplementedError()
for result in results[:]:
values = self._possible_values(myvar, ovar, result[ovar],
solutions, 's_')
expand_result(results, result, myvar, values, self._dsget)
else:
assert self.rhs.name in results[0]
self.object_complete_and_filter(solutions, results)
def filter(self, solutions, results):
myvar = self.rhs.name
ovar = self.var.name
newsols = {}
for result in results[:]:
entity = result[ovar]
key = entity.key()
if not key in newsols:
values = self._possible_values(myvar, ovar, entity, solutions, 's_')
newsols[key] = frozenset(v for v in values)
if self._not:
if result[myvar].key() in newsols[key]:
results.remove(result)
elif not result[myvar].key() in newsols[key]:
results.remove(result)
def object_complete_and_filter(self, solutions, results):
if self._not:
raise NotImplementedError()
myvar = self.var.name
ovar = self.rhs.name
for result in results[:]:
values = self._possible_values(myvar, ovar, result[ovar],
solutions, 'o_')
expand_result(results, result, myvar, values, self._dsget)
class EidRestriction(Restriction):
def __init__(self, rel, dsget):
Restriction.__init__(self, rel)
self._dsget = dsget
def resolve(self, kwargs):
value = self.rel.children[1].children[0].eval(kwargs)
return self._dsget(value)
class RelationRestriction(VariableSelection):
def _get_value(self, fixed):
return fixed[self.constraint_var].key()
def fill_query(self, fixed, query, operator=None):
restr = '%s%s %s' % (self._prefix, self.rtype, operator or self.operator)
query[restr] = self._get_value(fixed)
def resolve(self, solutions, fixed):
if self.rtype == 'identity':
if self._not:
raise NotImplementedError()
return [fixed[self.constraint_var]]
if self._not:
return _resolve_not([self], solutions, fixed)
return _resolve([self], solutions, fixed)
class NotRelationRestriction(RelationRestriction):
def _get_value(self, fixed):
return None
def resolve(self, solutions, fixed):
if self.rtype == 'identity':
raise NotImplementedError()
return _resolve([self], solutions, fixed)
class AttributeRestriction(RelationRestriction):
supported_operators = ('=', '>', '>=', '<', '<=', 'ILIKE')
def __init__(self, rel, kwargs):
RelationRestriction.__init__(self, rel, None)
value = self.rhs.eval(kwargs)
self.value = value
if self.operator == 'ILIKE':
if value.startswith('%'):
raise NotImplementedError('LIKE is only supported for prefix search')
if not value.endswith('%'):
raise NotImplementedError('LIKE is only supported for prefix search')
self.operator = '>'
self.value = value[:-1]
def complete_and_filter(self, solutions, results):
# check lhs var first in case this is a restriction
assert self._not
myvar, rtype, value = self.var.name, self.rtype, self.value
for result in results[:]:
if result[myvar].get('s_'+rtype) == value:
results.remove(result)
def _get_value(self, fixed):
return self.value
class DateAttributeRestriction(AttributeRestriction):
"""just a thin layer on top af `AttributeRestriction` that
tries to convert date strings such as in :
Any X WHERE X creation_date >= '2008-03-04'
"""
def __init__(self, rel, kwargs):
super(DateAttributeRestriction, self).__init__(rel, kwargs)
if isinstance(self.value, basestring):
# try:
self.value = datetime.strptime(self.value, '%Y-%m-%d')
# except Exception, exc:
# from logging import error
# error('unable to parse date %s with format %%Y-%%m-%%d (exc=%s)', value, exc)
class AttributeInRestriction(AttributeRestriction):
def __init__(self, rel, kwargs):
RelationRestriction.__init__(self, rel, None)
values = []
for c in self.rel.children[1].iget_nodes(nodes.Constant):
values.append(c.eval(kwargs))
self.value = values
@property
def operator(self):
return 'in'
class TypeRestriction(AttributeRestriction):
def __init__(self, var):
self.var = var
def __repr__(self):
return '<%s for %s>' % (self.__class__.__name__, self.var)
def resolve(self, solutions, fixed):
objs = []
for etype in frozenset(etypes[self.var.name] for etypes in solutions):
objs += Query(etype).Run()
return objs
def append_result(res, descr, i, j, value, etype):
if value is not None:
if isinstance(value, Text):
value = unicode(value)
elif isinstance(value, Blob):
value = Binary(str(value))
if j == 0:
res.append([value])
descr.append([etype])
else:
res[i].append(value)
descr[i].append(etype)
class ValueResolver(object):
def __init__(self, functions, args, term):
self.functions = functions
self.args = args
self.term = term
self._solution = self.term.stmt.solutions[0]
def compute(self, result):
"""return (entity type, value) to which self.term is evaluated according
to the given result dictionnary and to query arguments (self.args)
"""
return self.term.accept(self, result)
def visit_function(self, node, result):
args = tuple(n.accept(self, result)[1] for n in node.children)
value = self.functions[node.name](*args)
return node.get_type(self._solution, self.args), value
def visit_variableref(self, node, result):
value = result[node.name]
try:
etype = value.kind()
value = str(value.key())
except AttributeError:
etype = self._solution[node.name]
return etype, value
def visit_constant(self, node, result):
return node.get_type(kwargs=self.args), node.eval(self.args)
class RQLInterpreter(object):
"""algorithm:
1. visit the restriction clauses and collect restriction for each subject
of a relation. Different restriction types are:
* EidRestriction
* AttributeRestriction
* RelationRestriction
* VariableSelection (not really a restriction)
-> dictionary {<variable>: [restriction...], ...}
2. resolve eid restrictions
3. for each select in union:
for each solution in select'solutions:
1. resolve variables which have attribute restriction
2. resolve relation restriction
3. resolve selection and add to global results
"""
def __init__(self, schema):
self.schema = schema
Restriction.schema = schema # yalta!
self.rqlhelper = RQLHelper(schema, {'eid': etype_from_key})
self._stored_proc = {'LOWER': lambda x: x.lower(),
'UPPER': lambda x: x.upper()}
for cb in SQL_CONNECT_HOOKS.get('sqlite', []):
cb(self)
# emulate sqlite connection interface so we can reuse stored procedures
def create_function(self, name, nbargs, func):
self._stored_proc[name] = func
def create_aggregate(self, name, nbargs, func):
self._stored_proc[name] = func
def execute(self, operation, parameters=None, eid_key=None, build_descr=True):
rqlst = self.rqlhelper.parse(operation, annotate=True)
try:
self.rqlhelper.compute_solutions(rqlst, kwargs=parameters)
except BadKeyError:
results, description = [], []
else:
results, description = self.interpret(rqlst, parameters)
return ResultSet(results, operation, parameters, description, rqlst=rqlst)
def interpret(self, node, kwargs, dsget=None):
if dsget is None:
self._dsget = Get
else:
self._dsget = dsget
try:
return node.accept(self, kwargs)
except NotImplementedError:
self.critical('support for query not implemented: %s', node)
raise
def visit_union(self, node, kwargs):
results, description = [], []
extra = {'kwargs': kwargs}
for child in node.children:
pres, pdescr = self.visit_select(child, extra)
results += pres
description += pdescr
return results, description
def visit_select(self, node, extra):
constraints = {}
if node.where is not None:
node.where.accept(self, constraints, extra)
fixed, toresolve, postresolve, postfilters = {}, {}, {}, []
# extract NOT filters
for vname, restrictions in constraints.items():
for restr in restrictions[:]:
if isinstance(restr, AttributeRestriction) and restr._not:
postfilters.append(restr)
restrictions.remove(restr)
if not restrictions:
del constraints[vname]
# add TypeRestriction for variable which have no restrictions at all
for varname, var in node.defined_vars.iteritems():
if not varname in constraints:
constraints[varname] = [TypeRestriction(var)]
#print node, constraints
# compute eid restrictions
kwargs = extra['kwargs']
for varname, restrictions in constraints.iteritems():
for restr in restrictions[:]:
if isinstance(restr, EidRestriction):
assert not varname in fixed
try:
value = restr.resolve(kwargs)
fixed[varname] = value
except EntityNotFoundError:
return [], []
restrictions.remove(restr)
#print 'fixed', fixed.keys()
# combine remaining restrictions
for varname, restrictions in constraints.iteritems():
for restr in restrictions:
if isinstance(restr, AttributeRestriction):
toresolve.setdefault(varname, []).append(restr)
elif isinstance(restr, NotRelationRestriction) or (
isinstance(restr, RelationRestriction) and
not restr.searched_var in fixed and restr.constraint_var in fixed):
toresolve.setdefault(varname, []).append(restr)
else:
postresolve.setdefault(varname, []).append(restr)
try:
if len(toresolve[varname]) > 1:
toresolve[varname] = MultipleRestriction(toresolve[varname])
else:
toresolve[varname] = toresolve[varname][0]
except KeyError:
pass
#print 'toresolve %s' % toresolve
#print 'postresolve %s' % postresolve
# resolve additional restrictions
if fixed:
partres = [fixed.copy()]
else:
partres = []
for varname, restr in toresolve.iteritems():
varpartres = partres[:]
try:
values = tuple(restr.resolve(node.solutions, fixed))
except EidMismatch, ex:
varname = ex.varname
value = ex.value
partres = [res for res in partres if res[varname] != value]
if partres:
continue
# some join failed, no possible results
return [], []
if not values:
# some join failed, no possible results
return [], []
if not varpartres:
# init results
for value in values:
partres.append({varname: value})
elif not varname in partres[0]:
# cartesian product
for res in partres:
res[varname] = values[0]
for res in partres[:]:
for value in values[1:]:
res = res.copy()
res[varname] = value
partres.append(res)
else:
# union
for res in varpartres:
for value in values:
res = res.copy()
res[varname] = value
partres.append(res)
#print 'partres', len(partres)
#print partres
# Note: don't check for empty partres since constant selection may still
# produce result at this point
# sort to get RelationRestriction before AttributeSelection
restrictions = sorted((restr for restrictions in postresolve.itervalues()
for restr in restrictions),
key=lambda x: not isinstance(x, RelationRestriction))
# compute stuff not doable in the previous step using datastore queries
for restr in restrictions + postfilters:
restr.complete_and_filter(node.solutions, partres)
if not partres:
# some join failed, no possible results
return [], []
if extra.pop('has_exists', False):
# remove potential duplicates introduced by exists
toremovevars = [v.name for v in node.defined_vars.itervalues()
if not v.scope is node]
if toremovevars:
newpartres = []
for result in partres:
for var in toremovevars:
del result[var]
if not result in newpartres:
newpartres.append(result)
if not newpartres:
# some join failed, no possible results
return [], []
partres = newpartres
if node.orderby:
for sortterm in reversed(node.orderby):
resolver = ValueResolver(self._stored_proc, kwargs, sortterm.term)
partres.sort(reverse=not sortterm.asc,
key=lambda x: resolver.compute(x)[1])
if partres:
if node.offset:
partres = partres[node.offset:]
if node.limit:
partres = partres[:node.limit]
if not partres:
return [], []
#print 'completed partres', _print_results(partres)
# compute results
res, descr = [], []
for j, term in enumerate(node.selection):
resolver = ValueResolver(self._stored_proc, kwargs, term)
if not partres:
etype, value = resolver.compute({})
# only constant selected
if not res:
res.append([])
descr.append([])
res[0].append(value)
descr[0].append(etype)
else:
for i, sol in enumerate(partres):
etype, value = resolver.compute(sol)
append_result(res, descr, i, j, value, etype)
#print '--------->', res
return res, descr
def visit_and(self, node, constraints, extra):
for child in node.children:
child.accept(self, constraints, extra)
def visit_exists(self, node, constraints, extra):
extra['has_exists'] = True
self.visit_and(node, constraints, extra)
def visit_not(self, node, constraints, extra):
for child in node.children:
child.accept(self, constraints, extra)
try:
extra.pop(node)
except KeyError:
raise NotImplementedError()
def visit_relation(self, node, constraints, extra):
if node.is_types_restriction():
return
rschema = self.schema.rschema(node.r_type)
neged = node.neged(strict=True)
if neged:
# ok, we *may* process this Not node (not implemented error will be
# raised later if we can't)
extra[node.parent] = True
if rschema.is_final():
self._visit_final_relation(rschema, node, constraints, extra)
elif neged:
self._visit_non_final_neged_relation(rschema, node, constraints)
else:
self._visit_non_final_relation(rschema, node, constraints)
def _visit_non_final_relation(self, rschema, node, constraints, not_=False):
lhs, rhs = node.get_variable_parts()
for v1, v2, prefix in ((lhs, rhs, 's'), (rhs, lhs, 'o')):
#if not_:
nbrels = len(v2.variable.stinfo['relations'])
#else:
# nbrels = len(v2.variable.stinfo['relations']) - len(v2.variable.stinfo['uidrels'])
if nbrels > 1:
constraints.setdefault(v1.name, []).append(
RelationRestriction(node, self._dsget, prefix))
# just init an empty list for v2 variable to avoid a
# TypeRestriction being added for it
constraints.setdefault(v2.name, [])
break
else:
constraints.setdefault(rhs.name, []).append(
VariableSelection(node, self._dsget, 's'))
def _visit_non_final_neged_relation(self, rschema, node, constraints):
lhs, rhs = node.get_variable_parts()
for v1, v2, prefix in ((lhs, rhs, 's'), (rhs, lhs, 'o')):
stinfo = v2.variable.stinfo
if not stinfo['selected'] and len(stinfo['relations']) == 1:
constraints.setdefault(v1.name, []).append(
NotRelationRestriction(node, self._dsget, prefix))
constraints.setdefault(v2.name, [])
break
else:
self._visit_non_final_relation(rschema, node, constraints, True)
def _visit_final_relation(self, rschema, node, constraints, extra):
varname = node.children[0].name
if rschema.type == 'eid':
constraints.setdefault(varname, []).append(
EidRestriction(node, self._dsget))
else:
rhs = node.children[1].children[0]
if isinstance(rhs, nodes.VariableRef):
constraints.setdefault(rhs.name, []).append(
VariableSelection(node, self._dsget))
elif isinstance(rhs, nodes.Constant):
if rschema.objects()[0] in ('Datetime', 'Date'): # XXX
constraints.setdefault(varname, []).append(
DateAttributeRestriction(node, extra['kwargs']))
else:
constraints.setdefault(varname, []).append(
AttributeRestriction(node, extra['kwargs']))
elif isinstance(rhs, nodes.Function) and rhs.name == 'IN':
constraints.setdefault(varname, []).append(
AttributeInRestriction(node, extra['kwargs']))
else:
raise NotImplementedError()
def _not_implemented(self, *args, **kwargs):
raise NotImplementedError()
visit_or = _not_implemented
# shouldn't occurs
visit_set = _not_implemented
visit_insert = _not_implemented
visit_delete = _not_implemented
from logging import getLogger
from cubicweb import set_log_methods
set_log_methods(RQLInterpreter, getLogger('cubicweb.goa.rqlinterpreter'))
set_log_methods(Restriction, getLogger('cubicweb.goa.rqlinterpreter'))