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"""
Neo4j DB object
"""
from enum import Enum
from neo4j_cypher_parser import Cypher_Parser, e_clause__where, e_keyword, \
e_value, e_label_set, p_node, p_path, e_ident, p_rel
import re
import logging
import neo4j_cypher_parser
from decorator import __call__
log = logging.getLogger('rhizi')
class Query_Struct_Type(Enum):
unkown = 1
r = 2
w = 3
rw = 4
def __add__(self, other):
if self == other or self == Query_Struct_Type.rw:
return self
if self == Query_Struct_Type.unkown:
return other
if self == Query_Struct_Type.r and other != Query_Struct_Type.r:
return Query_Struct_Type.rw
if self == Query_Struct_Type.w and other != Query_Struct_Type.w:
return Query_Struct_Type.rw
def __str__(self):
if self == Query_Struct_Type.unkown: return 'unkown'
if self == Query_Struct_Type.r: return 'r'
if self == Query_Struct_Type.w: return 'w'
if self == Query_Struct_Type.rw: return 'rw'
assert False
def __eq__(self, other): # allow comparing against r/w/rw strings
if other in ['r', 'w', 'rw']:
if self == Query_Struct_Type.r and other == 'r': return True
if self == Query_Struct_Type.w and other == 'w': return True
if self == Query_Struct_Type.rw and other == 'rw': return True
if not isinstance(other, Query_Struct_Type): return False
return super(Query_Struct_Type, self).__eq__(other)
class Query_Transformation(object):
"""
A query transformation, which may be applied to either a DB_op or a DB_Query
"""
def __call__(self, value):
q_set = []
if isinstance(value, DB_Query):
q_set.append(value)
else: # assume iterable
assert hasattr(value, '__iter__')
for dbq in value:
assert isinstance(dbq, DB_Query)
q_set.append(dbq)
for dbq in q_set:
log.debug('%r' % (dbq))
self.apply_to_single_query(dbq)
log.debug('%r' % (dbq))
return value
def apply_to_single_query(self, dbq):
pass
class QT_RZDOC_NS_Filter__common(Query_Transformation):
"""
Add RZDoc name-space filter:
- inject NS labels into node patterns
- [!] ignore nodes which are part of path patterns to avoid overriding bound references
"""
def __init__(self, ns_label):
self.ns_label = ns_label
def apply_to_single_query(self, dbq):
rgx__doc_label = re.compile(r'%s[\w\d_]+' % (neo4j_schema.META_LABEL__RZDOC_NS_PREFIX))
assert None == rgx__doc_label.match(self.ns_label), 'Illegal doc ID label: %s' % (self.ns_label) # validate doc label
q_type = dbq.query_struct_type
clause_set = []
if Query_Struct_Type.w == q_type:
clause_set += dbq.pt_root.clause_set_by_kw('create')
if Query_Struct_Type.r == q_type:
clause_set += dbq.pt_root.clause_set_by_kw('match')
if Query_Struct_Type.rw == q_type:
clause_set += dbq.pt_root.clause_set_by_kw('create')
clause_set += dbq.pt_root.clause_set_by_kw('match')
for c in clause_set:
n_exp_set = c.sub_exp_set_by_type(p_node , recurse=True)
for n_exp in n_exp_set:
if n_exp.parent.__class__ == p_path:
continue;
lbl_set = n_exp.label_set
if not lbl_set: # add label set if necessary
lbl_set = n_exp.spawn_label_set()
lbl_set.add_label(self.ns_label)
# log.debug('db_q trans: in clause: %s, out clause: %s' % (cur_clause, new_clause))
class QT_RZDOC_NS_Filter(QT_RZDOC_NS_Filter__common):
def __init__(self, rzdoc):
ns_label = rzdoc__ns_label(rzdoc)
super(QT_RZDOC_NS_Filter, self).__init__(ns_label)
class QT_RZDOC_Meta_NS_Filter(QT_RZDOC_NS_Filter__common):
def __init__(self, rzdoc):
ns_label = rzdoc__meta_ns_label(rzdoc)
super(QT_RZDOC_Meta_NS_Filter, self).__init__(ns_label)
class QT_Node_Filter__meta_label_set(Query_Transformation):
# TODO: impl
# 'where 0 = length(filter(_lbl in labels(n) where _lbl =~ \'^__.*$\'))', # filter nodes with meta labels
pass
class DB_Query(object):
def __init__(self, q_arr, param_set={}):
"""
@param q_str_or_array: cypher query to add - if passed as an array ' '.join(q_str_or_array)
is used to convert it to string type
"""
assert type(q_arr) is list
# establish query type
self.q_str = ' '.join(q_arr) # FIXME: rm
self.pt_root = Cypher_Parser().parse_expression(self.q_str)
self.param_set = param_set
def __str__(self):
return self.pt_root.str__cypher_query()
def __repr__(self):
return 'q: %s, params: %s\n%s' % (self.pt_root.str__cypher_query(),
self.param_set,
self.pt_root.str__struct_tree())
def __iter__(self):
for keyword, clause_set in self.pt_root.index__kw_to_clause_set().items():
yield keyword, clause_set
def t__add_node_filter__meta_label(self):
if Query_Struct_Type.w == self.query_struct_type:
return
meta_label_cond = '0 = length(filter(_lbl in labels(n) where _lbl in {meta_label_set}))' # filter nodes with meta labels
c_set__where = self.pt_root.clause_set_by_kw('where')
if not c_set__where:
c_set__match = self.pt_root.clause_set_by_kw('match')
first_match_clause = c_set__match.pop()
wc = first_match_clause.spawn_sibling__adjacent(e_clause__where)
wc.spawn_child(e_keyword, 'where')
wc.spawn_child(e_value).value = meta_label_cond
else: # where clause present
assert len(c_set__where) == 1, 't__add_node_filter__meta_label: no support for multi-where clauses query transformation'
wc = c_set__where[0]
wc_cond = wc.condition_value
wc.set_condition(meta_label_cond + ' and ' + wc_cond)
self.param_set['meta_label_set'] = meta_label_set
@property
def query_struct_type(self):
"""
calc query_structure_type: read|write|read-write
"""
r = False
w = False
for kw, _clause_set in self.pt_root.index__kw_to_clause_set().items():
if kw in neo4j_cypher_parser.tok_set__kw__write:
w = True
if kw == 'match':
r = True
if r and w: return Query_Struct_Type.rw
if r and not w: return Query_Struct_Type.r
if w and not r: return Query_Struct_Type.w
return Query_Struct_Type.unkown
def str__cypher_query(self):
return self.pt_root.str__cypher_query()
class DB_row(object):
def __init__(self, data):
self.data = data
def __iter__(self):
for column_val in self.data:
yield column_val
def items(self):
return [x for x in self]
def __str__(self):
return str(self.items())
def __repr__(self):
return repr(self.items())
class DB_result_set(object):
def __init__(self, data):
self.data = data
def __iter__(self):
for db_row_dict in self.data['data']:
# example: dict: {u'row': [{u'title': u'foo'}]}
assert None != db_row_dict['row']
yield DB_row(db_row_dict['row'])
def items(self):
return [x for x in self]
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