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#!/usr/bin/python
import os
import json
import re
import logging
import traceback
import urllib2
import neo4j_util as dbu
log = logging.getLogger('rhizi')
class DB_op(object):
"""
tx wrapped DB operation possibly composing multiple DB queries
"""
def __init__(self):
self.s_id = 0 # statement id counter
self.id_to_statement_map = {} # zero based id to statement map
self.tx_id = None
self.tx_commit_url = None # cached from response to tx begin
def begin(self, tx_open_url):
try:
#
# [!] neo4j seems picky about receiving an additional empty statement list
#
data = data = dbu.statement_set_to_REST_form([])
ret = dbu.post_neo4j(tx_open_url, data)
tx_commit_url = ret['commit']
self.parse_tx_id(tx_commit_url)
self.tx_commit_url = tx_commit_url
log.debug('tx-open: id: {0}, commit-url: {1}'.format(self.tx_id, tx_commit_url))
except Exception as e:
raise Exception('failed to open transaction:' + e.message)
def parse_tx_id(self, tx_commit_url):
m = re.search('/(?P<id>\d+)/commit$', tx_commit_url)
id_str = m.group('id')
self.tx_id = int(id_str)
def commit(self):
try:
#
# [!] neo4j seems picky about receiving an additional empty statement list
#
data = dbu.statement_set_to_REST_form([])
ret = dbu.post(self.tx_commit_url, data)
except Exception as e:
raise Exception('failed to commit transaction:' + e.message)
log.debug('tx-commit: id: {0}, commit-url: {1}'.format(self.tx_id, self.tx_commit_url))
def add_statement(self, cypher_query, params={}):
"""
add a DB query language statement
@return: statement id
"""
ret = self.s_id
self.id_to_statement_map[self.s_id] = dbu.statement_to_REST_form(cypher_query, params)
self.s_id = self.s_id + 1
return ret
@property
def statement_set(self):
return self.id_to_statement_map.values()
def on_success(self, data):
pass
def on_error(self):
pass
class DBO_add_node_set(DB_op):
"""
DB op: add node set
@param node_map: node-type to node list map
@input_to_DB_property_map: optional function which takes a map of input properties and returns a map of DB properties - use to map input schemas to DB schemas
"""
def __init__(self, node_map, input_to_DB_property_map=lambda _: _):
super(DBO_add_node_set, self).__init__()
self.node_map = node_map
for type, n_set in self.node_map.items():
q = "create (n:{0} {{prop_dict}}) return id(n)".format(type)
for n_prop_dict in n_set:
p = {'prop_dict' : input_to_DB_property_map(n_prop_dict)}
self.add_statement(q, p)
def on_success(self, data):
# [!] fragile - parse results
# sample input: dict: {u'errors': [], u'results': [{u'data': [{u'row': [20]}], u'columns': [u'id(n)']}]}
id_set = []
for r in data['results']:
columns = r['columns']
for k in r['data']:
nid = k['row'][0]
id_set.append(nid)
log.debug('node-set added: ids: ' + str(id_set))
return id_set
class DBO_load_node_id_set(DB_op):
"""
load node id set, filter by type / properties
"""
def __init__(self, filter_type, filter_prop=None):
super(DBO_load_node_id_set, self).__init__()
# build where clause if necessary
filter_prop_str = ""
if filter_prop:
filter_prop_arr = []
for k, v in filter_prop:
v_str = str(v)
if isinstance(v, str):
# quote string values
v_str = "'{0}'".format(v_str)
filter_prop_arr.append("n.{0} = {1} and ".format(k, v_str))
filter_prop_str = " where " + " and ".join(filter_prop_arr)
q = "match (n:{0}){1} return id(n)".format(filter_type, filter_prop_str)
self.add_statement(q)
def on_success(self, data):
# [!] fragile - parse results
# sample input: dict: {u'errors': [], u'results': [{u'data': [{u'row': [20]}], u'columns': [u'id(n)']}]}
id_set = []
for r in data['results']:
columns = r['columns']
for k in r['data']:
nid = k['row'][0]
id_set.append(nid)
log.debug('loaded node id set: ' + str(id_set))
return id_set
class DB_Controller:
"""
neo4j DB controller
"""
def __init__(self, config):
self.config = config
def log_committed_queries(self, statement_set):
for sp_dict in statement_set['statements']:
log.debug('\tq: {0}'.format(sp_dict['statement']))
def exec_op(self, op):
"""
execute operation within a DB transaction
"""
tx_base_url = self.config.db_base_url + '/db/data/transaction'
statement_set = dbu.statement_set_to_REST_form(op.statement_set)
try:
op.begin(tx_base_url)
tx_url = "{0}/{1}".format(tx_base_url, op.tx_id)
ret_tx = dbu.post_neo4j(tx_url, statement_set)
op.commit()
self.log_committed_queries(statement_set)
return op.on_success(ret_tx)
except Exception as e:
log.error(e.message)
log.error(traceback.print_exc())
op.on_error()
def create_db_op(self, f_work, f_cont):
ret = DB_op(f_work, f_cont)
return ret
def exec_cypher_query(self, q):
"""
@deprecated: use transaction based api
"""
self.post_neo4j('/db/data/cypher', {"query" : q})
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