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"""
Utility code in speaking the neo4j REST api
"""
import json
import urllib2
def post_neo4j(url, data):
"""
@return dict object from the neo4j json POST response
@raise exception: if the 'errors' key is not empty
"""
ret = post(url, data)
ret_data = json.load(ret)
if ret_data['errors']:
raise Exception('neo4j exception: ' + str(ret_data['errors']))
return ret_data
def post(url, data):
assert(isinstance(data, dict)) # make sure we're not handed json strings
post_data_json = json.dumps(data)
req = urllib2.Request(url)
req.add_header('User-Agent', 'rhizi-server/0.1')
req.add_header('Accept', 'application/json; charset=UTF-8')
req.add_header('Content-Type', 'application/json')
try:
ret = urllib2.urlopen(req, post_data_json)
except urllib2.HTTPError as e:
raise Exception('post request failed: code: {0}, reason: {1}'.format(e.code, e.reason))
return ret
def statement_to_REST_form(query, parameters={}):
"""
turn cypher query to neo4j json API format
"""
assert isinstance(query, basestring)
assert isinstance(parameters, dict)
return {'statement' : query, 'parameters': parameters}
def statement_set_to_REST_form(statement_set):
assert isinstance(statement_set, list)
return {'statements': statement_set}
def where_clause_from_filter_attr_map(filter_attr_map, node_param_name="n"):
"""
convert a filter attribute map to a parameterized Cypher where clause, eg.
in: { 'att_foo': [ 'a', 'b' ], 'att_goo': [1,2] }
out: where n.att_foo in {att_foo} and n.att_goo in {att_goo} ...
@param filter_attr_map: may be None or empty
"""
if not filter_attr_map:
return ""
filter_arr = []
for k in filter_attr_map.keys():
# create a cypher query parameter place holder for each attr set
# eg. n.foo in {foo}, where foo is passed as a query parameter
f_attr = "{0}.{1} in {{{1}}}".format(node_param_name, k)
filter_arr.append(f_attr)
filter_str = "where {0}".format(' and '.join(filter_arr))
return filter_str
def create_query_from_node_map(node_map, input_to_DB_property_map=lambda _: _):
"""
generate a set of node create queries
@param node_map: is a node-type to node 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
@return: a (query, query_parameteres) set of create queries
"""
ret = []
for n_type, n_set in node_map.items():
q = "create (n:{0} {{prop_dict}}) return id(n)".format(n_type)
for n_prop_set in n_set:
q_params = {'prop_dict' : input_to_DB_property_map(n_prop_set)}
ret.append((q, q_params))
return ret
def create_query_from_link_map(link_map, input_to_DB_property_map=lambda _: _):
"""
generate a set of link create queries
@param link_map: is a link-type to link map - see model.link
"""
ret = []
for l_type, l_set in link_map.items():
for link in l_set:
__type_check_link(link)
n_src = link['__src']
n_dst = link['__dst']
# TODO: use object based link representation
prop_dict = link.copy()
del prop_dict['__dst']
del prop_dict['__src']
q = "create ({ns})-[:{lt} {{prop_dict}}]-({nd})".format(ns=n_src, lt=l_type, nd=n_dst)
q_params = {'prop_dict' : input_to_DB_property_map(prop_dict)}
ret.append((q, q_params))
return ret
def __type_check_link(link):
assert link.has_key('__src')
assert link.has_key('__dst')
def __type_check_filter_attr_map(filter_attr_map):
"""
# type sanity check an attribute filter map
"""
assert isinstance(filter_attr_map, dict)
for k, v in filter_attr_map.items():
assert isinstance(k, basestring)
assert isinstance(v, list)
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