def test_attr2rdf_period():
"""
Check that attr2rdf handles minus symbol in predicate names.
"""
uriref, _ = attr2rdf("surf_predicate-with-minus")
assert uriref == surf.ns.SURF["predicate-with-minus"]
def test_attr2rdf_period():
"""
Check that attr2rdf handles minus symbol in predicate names.
"""
uriref, _ = attr2rdf("surf_predicate-with-minus")
assert uriref == surf.ns.SURF["predicate-with-minus"]
def __getattr__(self, attr_name):
""" Retrieve and cache attribute values.
If attribute name is not in the "ns_predicate" form, an
`AttributeError` will be raised.
This method has no impact on the *dirty* state of the object.
"""
predicate, direct = attr2rdf(attr_name)
if not predicate:
raise AttributeError('Not a predicate: %s' % attr_name)
# Prepare closure for lazy execution.
def prepare_getvalues_callable(resource, predicate, direct, retrieve):
""" Return callable that loads and returns values. """
def getvalues_callable():
""" Load and return values for this attribute. """
# Select triple dictionary for synchronization
rdf_dict = resource.__rdf_direct if direct else resource.__rdf_inverse
# Initial synchronization
if retrieve:
store = resource.session[resource.store_key]
# send request to triple store
values = store.get(resource, predicate, direct)
if not values:
predicate_values = rdf_dict.get(predicate, [])
values.update([(pred_val, [])
for pred_val in predicate_values])
# instantiate SuRF objects
surf_values = resource._lazy(values)
else:
surf_values = []
rdf_dict[predicate] = [
resource.to_rdf(value) for value in surf_values
]
return surf_values, rdf_dict[predicate]
return getvalues_callable
# If resource is fully loaded and we're still here (__getattr__), this must be an empty
# attribute, therefore there is no point in querying the triple store !
retrieve_values = (not self.__full_direct) if direct else (
not self.__full_inverse)
getvalues_callable = prepare_getvalues_callable(
self, predicate, direct, retrieve_values)
attr_value = LazyResourceLoader(getvalues_callable, self, attr_name)
# Not using self.__setattr__, that would trigger loading of attributes
# object.__setattr__(self, attr_name, attr_value)
super(Resource, self).__setattr__(attr_name, attr_value)
self.dirty = False
return attr_value
def get_by_attribute(cls, attributes, context = None):
"""
Retrieve all `instances` from the data store that have the specified `attributes`
and are of `rdf:type` of the resource class
"""
direct_attributes = []
inverse_attributes = []
attribute_uris = [inverse_attributes, direct_attributes]
for attribute_name in attributes:
attribute_uri, direct = attr2rdf(attribute_name)
# Using boolean as array index.
attribute_uris[direct].append(attribute_uri)
subjects = {}
if direct_attributes:
subjects.update(cls.session[cls.store_key].instances_by_attribute(cls, direct_attributes, True, context))
if inverse_attributes:
subjects.update(cls.session[cls.store_key].instances_by_attribute(cls, inverse_attributes, False, context))
instances = []
for s, types in subjects.items():
if not isinstance(s, URIRef):
continue
if cls.uri:
concepts = [cls.uri]
else:
concepts = types
instances.append(cls._instance(s, concepts))
return instances
def get_by(self, **kwargs):
""" Add filter conditions.
Arguments are expected in form::
foaf_name = "John"
Multiple arguments are supported.
An example that retrieves all persons named "John Smith"::
FoafPerson = session.get_class(surf.ns.FOAF.Person)
for person in FoafPerson.get_by(foaf_name = "John", foaf_surname = "Smith"):
print person.subject
"""
params = self.__params.copy()
# Don't overwrite existing get_by parameters, just append new ones.
# Overwriting get_by params would cause resource.some_attr.get_by()
# to work incorrectly.
params.setdefault("get_by", [])
for name, value in kwargs.items():
attr, direct = attr2rdf(name)
# Assume by plain strings user means literals
if type(value) in [str, unicode]:
value = Literal(value)
# If value has subject attribute, this must be Resource,
# take its subject.
if hasattr(value, "subject"):
value = value.subject
params["get_by"].append((attr, value, direct))
return ResultProxy(params)
def __getattr__(self, attr_name):
""" Retrieve and cache attribute values.
If attribute name is not in the "ns_predicate" form, an
`AttributeError` will be raised.
This method has no impact on the *dirty* state of the object.
"""
predicate, direct = attr2rdf(attr_name)
if not predicate:
raise AttributeError('Not a predicate: %s' % attr_name)
# Closure for lazy execution.
def make_values_source(resource, predicate, direct, do_query):
""" Return callable that loads and returns values. """
def getattr_values_source():
""" Load and return values for this attribute. """
if do_query:
store = resource.session[resource.store_key]
# Request to triple store
values = store.get(resource, predicate, direct)
# Instantiate SuRF objects
surf_values = resource._lazy(values)
else:
surf_values = []
# Select triple dictionary for synchronization
if direct:
rdf_dict = resource.__rdf_direct
else:
rdf_dict = resource.__rdf_inverse
# Initial synchronization
rdf_dict[predicate] = [resource.to_rdf(value) for value in surf_values]
return surf_values, rdf_dict[predicate]
return getattr_values_source
# If resource is fully loaded and still we're here
# at __getattr__, this must be an empty attribute, so
# no point querying triple store.
do_query = not self.__full
values_source = make_values_source(self, predicate, direct, do_query)
attr_value = ResourceValue(values_source, self, attr_name)
# Not using self.__setattr__, that would trigger loading of attributes
object.__setattr__(self, attr_name, attr_value)
self.dirty = False
return attr_value
def __getattr__(self, attr_name):
""" Retrieve and cache attribute values.
If attribute name is not in the "ns_predicate" form, an
`AttributeError` will be raised.
This method has no impact on the *dirty* state of the object.
"""
predicate, direct = attr2rdf(attr_name)
if not predicate:
raise AttributeError('Not a predicate: %s' % attr_name)
# Prepare closure for lazy execution.
def prepare_getvalues_callable(resource, predicate, direct, retrieve):
""" Return callable that loads and returns values. """
def getvalues_callable():
""" Load and return values for this attribute. """
# Select triple dictionary for synchronization
rdf_dict = resource.__rdf_direct if direct else resource.__rdf_inverse
# Initial synchronization
if retrieve:
store = resource.session[resource.store_key]
# send request to triple store
values = store.get(resource, predicate, direct)
if not values:
predicate_values = rdf_dict.get(predicate,[])
values.update([(pred_val, []) for pred_val in predicate_values])
# instantiate SuRF objects
surf_values = resource._lazy(values)
else:
surf_values = []
rdf_dict[predicate] = [resource.to_rdf(value) for value in surf_values]
return surf_values, rdf_dict[predicate]
return getvalues_callable
# If resource is fully loaded and we're still here (__getattr__), this must be an empty
# attribute, therefore there is no point in querying the triple store !
retrieve_values = (not self.__full_direct) if direct else (not self.__full_inverse)
getvalues_callable = prepare_getvalues_callable(self, predicate, direct, retrieve_values)
attr_value = LazyResourceLoader(getvalues_callable, self, attr_name)
# Not using self.__setattr__, that would trigger loading of attributes
# object.__setattr__(self, attr_name, attr_value)
super(Resource, self).__setattr__(attr_name, attr_value)
self.dirty = False
return attr_value
def split_attribute_edges(name):
""" Allow specifying indirect attributes by giving a path of properties
from the object up to the requested attribute """
edges = []
for edge in name.split('__'):
attr, direct = attr2rdf(edge)
if attr is None:
raise ValueError("Not an attribute %r" % edge)
edges.append((attr, direct))
return edges
def split_attribute_edges(name):
""" Allow specifying indirect attributes by giving a path of properties
from the object up to the requested attribute """
edges = []
for edge in name.split("__"):
attr, direct = attr2rdf(edge)
if attr is None:
raise ValueError("Not an attribute %r" % edge)
edges.append((attr, direct))
return edges
def __uri(self, uri):
""" For **internal** use only, convert the `uri` to a `URIRef`. """
if not uri:
return None
if type(uri) is URIRef:
return uri
else:
if not is_uri(uri):
attrname = de_camel_case(uri, '_', DE_CAMEL_CASE_DEFAULT)
uri, _ = attr2rdf(attrname)
return URIRef(uri)
def __uri(self, uri):
""" For **internal** use only, convert the `uri` to a `URIRef`. """
if not uri:
return None
if type(uri) is URIRef:
return uri
else:
if not is_uri(uri):
attrname = de_camel_case(uri, '_', DE_CAMEL_CASE_DEFAULT)
uri, _ = attr2rdf(attrname)
return URIRef(uri)
def query_attribute(self, attribute_name):
""" Return ResultProxy for querying attribute values. """
# If we want to get john.foaf_knows values, we have to formulate
# query like friends = get_by(is_foaf_knows_of = john), thus the
# attribute name inversion
uri, direct = attr2rdf(attribute_name)
inverse_attribute_name = unicode(rdf2attr(uri, not direct))
store = self.session[self.store_key]
proxy = ResultProxy(store = store,
instancemaker = self.__instancemaker)
kwargs = {inverse_attribute_name : self.subject}
return proxy.get_by(**kwargs)
def __delattr__(self, attr_name):
"""
The `del` method - responsible for deleting the attribute of the object given
by `attr_name`
.. note:: This method sets the state of the resource to *dirty*
(the `resource` will be persisted if the `commit` `session`
method is called)
"""
predicate, direct = attr2rdf(attr_name)
if predicate:
#value = self.__getattr__(attr_name)
rdf_dict = direct and self.__rdf_direct or self.__rdf_inverse
rdf_dict[predicate] = []
self.dirty = True
object.__delattr__(self, attr_name)
def __delattr__(self, attr_name):
"""
The `del` method - responsible for deleting the attribute of the object given
by `attr_name`
.. note:: This method sets the state of the resource to *dirty*
(the `resource` will be persisted if the `commit` `session`
method is called)
"""
predicate, direct = attr2rdf(attr_name)
if predicate:
#value = self.__getattr__(attr_name)
rdf_dict = direct and self.__rdf_direct or self.__rdf_inverse
rdf_dict[predicate] = []
self.dirty = True
object.__delattr__(self, attr_name)
def query_attribute(self, attribute_name):
""" Return ResultProxy for querying attribute values. """
# If we want to get john.foaf_knows values, we have to formulate
# query like friends = get_by(is_foaf_knows_of = john), thus the
# attribute name inversion
uri, direct = attr2rdf(attribute_name)
# We'll be using inverse_attribute_name as keyword argument.
# Python 2.6.2 and older don't allow unicode keyword arguments,
# so we revert back to str().
inverse_attribute_name = str(rdf2attr(uri, not direct))
store = self.session[self.store_key]
proxy = ResultProxy(store=store,
instance_factory=self.__instance_factory)
kwargs = {inverse_attribute_name: self.subject}
return proxy.get_by(**kwargs)
def query_attribute(self, attribute_name):
""" Return ResultProxy for querying attribute values. """
# If we want to get john.foaf_knows values, we have to formulate
# query like friends = get_by(is_foaf_knows_of = john), thus the
# attribute name inversion
uri, direct = attr2rdf(attribute_name)
# We'll be using inverse_attribute_name as keyword argument.
# Python 2.6.2 and older doesn't allow unicode keyword arguments,
# so we do str().
inverse_attribute_name = str(rdf2attr(uri, not direct))
store = self.session[self.store_key]
proxy = ResultProxy(store = store,
instancemaker = self.__instancemaker)
kwargs = {inverse_attribute_name : self.subject}
return proxy.get_by(**kwargs)
def __setattr__(self, name, value):
"""
The `set` method - responsible for *caching* the `value` to the
corresponding object attribute given by `name`.
.. note: This method sets the state of the resource to *dirty*
(the `resource` will be persisted if the `commit` `session` method
is called).
"""
def make_values_source(values, rdf_values):
""" Return callable that returns stored values for this attr. """
def setattr_values_source():
""" Return stored values for this attribute. """
return values, rdf_values
return setattr_values_source
predicate, direct = attr2rdf(name)
if predicate:
rdf_dict = direct and self.__rdf_direct or self.__rdf_inverse
if not isinstance(value, list):
value = [value]
rdf_dict[predicate] = []
rdf_dict[predicate].extend([self.to_rdf(val) for val in value])
self.dirty = True
if type(value) is ResourceValue:
pass
else:
if type(value) not in [list, tuple]:
value = [value]
value = map(value_to_rdf, value)
values_source = make_values_source(value, rdf_dict[predicate])
value = ResourceValue(values_source, self, name)
object.__setattr__(self, name, value)
def get_by(self, **kwargs):
""" Add filter conditions.
Arguments are expected in form::
foaf_name = "John"
Multiple arguments are supported.
An example that retrieves all persons named "John Smith"::
FoafPerson = session.get_class(surf.ns.FOAF.Person)
for person in FoafPerson.get_by(foaf_name = "John", foaf_surname = "Smith"):
print person.subject
"""
params = self._params.copy()
# Don't overwrite existing get_by parameters, just append new ones.
# Overwriting get_by params would cause resource.some_attr.get_by()
# to work incorrectly.
params.setdefault("get_by", [])
for name, value in kwargs.items():
attr, direct = attr2rdf(name)
if hasattr(value, "subject"):
# If value has a subject attribute, this must be a Resource,
# take its subject.
value = value.subject
elif not isinstance(value, basestring) and hasattr(
value, "__iter__"):
# Map alternatives
value = [
hasattr(val, "subject") and val.subject
or value_to_rdf(val) for val in value
]
else:
value = value_to_rdf(value)
params["get_by"].append((attr, value, direct))
return ResultProxy(params)
def get_by(self, **kwargs):
""" Add filter conditions.
Arguments are expected in form::
foaf_name = "John"
Multiple arguments are supported.
An example that retrieves all persons named "John Smith"::
FoafPerson = session.get_class(surf.ns.FOAF.Person)
for person in FoafPerson.get_by(foaf_name = "John", foaf_surname = "Smith"):
print person.subject
"""
params = self.__params.copy()
# Don't overwrite existing get_by parameters, just append new ones.
# Overwriting get_by params would cause resource.some_attr.get_by()
# to work incorrectly.
params.setdefault("get_by", [])
for name, value in kwargs.items():
attr, direct = attr2rdf(name)
if hasattr(value, "subject"):
# If value has a subject attribute, this must be a Resource,
# take its subject.
value = value.subject
elif hasattr(value, "__iter__"):
# Map alternatives
value = map(lambda val: hasattr(val, "subject")
and val.subject
or value_to_rdf(val),
value)
else:
value = value_to_rdf(value)
params["get_by"].append((attr, value, direct))
return ResultProxy(params)
def __setattr__(self, name, value):
"""
The `set` method - responsible for *caching* the `value` to the
corresponding object attribute given by `name`.
.. note: This method sets the state of the resource to *dirty*
(the `resource` will be persisted if the `commit` `session` method
is called).
"""
def prepare_getvalues_callable(values, rdf_values):
""" Return callable that returns stored values for this attr. """
def getvalues_callable():
""" Return stored values for this attribute. """
return values, rdf_values
return getvalues_callable
predicate, direct = attr2rdf(name)
if predicate:
rdf_dict = direct and self.__rdf_direct or self.__rdf_inverse
if not isinstance(value, list):
value = [value]
rdf_dict[predicate] = []
rdf_dict[predicate].extend([self.to_rdf(val) for val in value])
self.dirty = True
if type(value) is LazyResourceLoader:
pass
else:
if type(value) not in [list, tuple]:
value = [value]
value = list(map(value_to_rdf, value))
getvalues_callable = prepare_getvalues_callable(
value, rdf_dict[predicate])
value = LazyResourceLoader(getvalues_callable, self, name)
object.__setattr__(self, name, value)
def filter(self, **kwargs):
""" Add filter conditions.
Expects arguments in form::
ns_predicate = "(%s > 15)"
``ns_predicate`` specifies which predicate will be used for
filtering, a query variable will be bound to it. `%s` is a placeholder
for this variable.
Filter expression (in example: "(%s > 15)") must follow SPARQL
specification, on execution "%s" will be substituted with variable
and the resulting string will be placed in query as-is. Because of
string substitution percent signs need to be escaped. For example::
Person.all().filter(foaf_name = "(%s LIKE 'J%%')")
This Virtuoso-specific filter is intended to select persons with names starting with
"J". In generated query it will look like this::
...
?s <http://xmlns.com/foaf/0.1/name> ?f1 .
FILTER (?f1 LIKE 'J%')
...
"""
params = self.__params.copy()
params.setdefault("filter", [])
for name, value in kwargs.items():
attr, direct = attr2rdf(name)
assert direct, "Only direct attributes can be used for filters"
# Assume by plain strings user means literals
if type(value) in [str, unicode]:
value = Literal(value)
params["filter"].append((attr, value, direct))
return ResultProxy(params)
def filter(self, **kwargs):
""" Add filter conditions.
Expects arguments in form::
ns_predicate = "(%s > 15)"
``ns_predicate`` specifies which predicate will be used for
filtering, a query variable will be bound to it. `%s` is a placeholder
for this variable.
Filter expression (in example: "(%s > 15)") must follow SPARQL
specification, on execution "%s" will be substituted with variable
and the resulting string will be placed in query as-is. Because of
string substitution percent signs need to be escaped. For example::
Person.all().filter(foaf_name = "(%s LIKE 'J%%')")
This Virtuoso-specific filter is intended to select persons with names starting with
"J". In generated query it will look like this::
...
?s <http://xmlns.com/foaf/0.1/name> ?f1 .
FILTER (?f1 LIKE 'J%')
...
"""
params = self.__params.copy()
params.setdefault("filter", [])
for name, value in kwargs.items():
attr, direct = attr2rdf(name)
assert direct, "Only direct attributes can be used for filters"
# Assume by plain strings user means literals
if type(value) in [str, unicode]:
value = Literal(value)
params["filter"].append((attr, value, direct))
return ResultProxy(params)
def get_by_attribute(cls, attributes, context=None):
"""
Retrieve all `instances` from the data store that have the specified `attributes`
and are of `rdf:type` of the resource class
"""
direct_attributes = []
inverse_attributes = []
attribute_uris = [inverse_attributes, direct_attributes]
for attribute_name in attributes:
attribute_uri, direct = attr2rdf(attribute_name)
# Using boolean as array index.
attribute_uris[direct].append(attribute_uri)
subjects = {}
if direct_attributes:
subjects.update(cls.session[cls.store_key].instances_by_attribute(
cls, direct_attributes, True, context))
if inverse_attributes:
subjects.update(cls.session[cls.store_key].instances_by_attribute(
cls, inverse_attributes, False, context))
instances = []
for s, types in list(subjects.items()):
if not isinstance(s, URIRef):
continue
if cls.uri:
concepts = [cls.uri]
else:
concepts = types
instances.append(cls._instance(s, concepts))
return instances
def test_attr2rdf_period(self):
""" Check that attr2rdf handles minus symbol in predicate names. """
uriref, _ = attr2rdf("surf_predicate-with-minus")
self.assertEquals(uriref, surf.ns.SURF["predicate-with-minus"])
def test_attr2rdf_period(self):
""" Check that attr2rdf handles minus symbol in predicate names. """
uriref, _ = attr2rdf("surf_predicate-with-minus")
self.assertEquals(uriref, surf.ns.SURF["predicate-with-minus"])
def __getattr__(self, attr_name):
""" Retrieve and cache attribute values.
If attribute name is not in the "ns_predicate" form, an
`AttributeError` will be raised.
This method has no impact on the *dirty* state of the object.
"""
predicate, direct = attr2rdf(attr_name)
if not predicate:
raise AttributeError('Not a predicate: %s' % attr_name)
# Closure for lazy execution.
def make_values_source(resource, predicate, direct, do_query):
""" Return callable that loads and returns values. """
def getattr_values_source():
""" Load and return values for this attribute. """
if do_query:
store = resource.session[resource.store_key]
# Request to triple store
values = store.get(resource, predicate, direct)
# Instantiate SuRF objects
surf_values = resource._lazy(values)
else:
surf_values = []
# Select triple dictionary for synchronization
if direct:
rdf_dict = resource.__rdf_direct
else:
rdf_dict = resource.__rdf_inverse
# Save query_contexts
for i in range(len(surf_values)):
if isinstance(surf_values[i], Resource):
surf_values[i].query_contexts = self.query_contexts
# Initial synchronization
rdf_dict[predicate] = [
resource.to_rdf(value) for value in surf_values
]
return surf_values, rdf_dict[predicate]
return getattr_values_source
# If resource is fully loaded and still we're here
# at __getattr__, this must be an empty attribute, so
# no point querying triple store.
do_query = not self.__full
values_source = make_values_source(self, predicate, direct, do_query)
attr_value = ResourceValue(values_source, self, attr_name)
# Not using self.__setattr__, that would trigger loading of attributes
object.__setattr__(self, attr_name, attr_value)
self.dirty = False
return attr_value
