[sqlalchemy] Re: How to jsonify Query result?
Ok, that approach isn't cool.. I get another one from flask_jsontools and
it does what I need!
json.dumps(q, cls=DynamicJSONEncoder)
Base = declarative_base(cls=JsonSerializableBase)
import decimal
from datetime import datetime, date
from json import JSONEncoder
from sqlalchemy import inspect
from sqlalchemy.orm.state import InstanceState
class DynamicJSONEncoder(JSONEncoder):
def default(self, obj):
if isinstance(obj, (datetime, date)):
return obj.isoformat()
elif isinstance(obj, decimal.Decimal):
return float(obj)
elif hasattr(obj, '__json__'):
return obj.__json__()
return super(DynamicJSONEncoder, self).default(obj)
def get_entity_propnames(entity):
ins = entity if isinstance(entity, InstanceState) else inspect(entity)
return set(ins.mapper.column_attrs.keys() + ins.mapper.relationships.keys())
def get_entity_loaded_propnames(entity):
Get entity property names that are loaded (e.g. won't produce new
queries)
ins = inspect(entity)
keynames = get_entity_propnames(ins)
# If the entity is not transient -- exclude unloaded keys
# Transient entities won't load these anyway, so it's safe to include all
columns and get defaults
if not ins.transient:
keynames -= ins.unloaded
# If the entity is expired -- reload expired attributes as well
# Expired attributes are usually unloaded as well!
if ins.expired:
keynames |= ins.expired_attributes
return keynames
class JsonSerializableBase(object):
Declarative Base mixin to allow objects serialization
__json_private__ = set()
def __json__(self):
return {name: getattr(self, name)
for name in get_entity_loaded_propnames(self) -
self.__json_private__}
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[sqlalchemy] Re: How to jsonify Query result?
I create Serializer class and use it for all my models with: Base =
declarative_base(cls=Serializer)
But I have one problem! I have Organization model and Service model that has
organization = relationship('Organization', backref='services') relationship
and I get RuntimeError: maximum recursion depth exceeded while calling a
Python object
What can I do with that? Help me please!
Traceback (most recent call last):
File s.py, line 10, in module
print repr(r.to_dict())
File /Users/sector119/PycharmProjects/epsilon/epsilon/models/serializer.py,
line 31, in to_dict
value = self._serialize(key, field.value)
File /Users/sector119/PycharmProjects/epsilon/epsilon/models/serializer.py,
line 48, in _serialize
result.append(cls._serialize(key, v))
File /Users/sector119/PycharmProjects/epsilon/epsilon/models/serializer.py,
line 51, in _serialize
result = value.to_dict()
File /Users/sector119/PycharmProjects/epsilon/epsilon/models/serializer.py,
line 31, in to_dict
...
...
...
File
/Users/sector119/PythonVirtualEnv/epsilon/lib/python2.7/site-packages/sqlalchemy/orm/state.py,
line 671, in value
self.state.obj(), self.state.class_)
File
/Users/sector119/PythonVirtualEnv/epsilon/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py,
line 233, in __get__
dict_ = instance_dict(instance)
RuntimeError: maximum recursion depth exceeded while calling a Python object
from datetime import datetime, date
from sqlalchemy.inspection import inspect
class Serializer(object):
__public__ = None
__private__ = None
def to_dict(self, exclude=(), extra=()):
data = {}
items = inspect(self).attrs.items()
if self.__public__:
public = self.__public__ + extra
else:
public = extra
if self.__private__:
private = self.__private__ + exclude
else:
private = exclude
for key, field in items:
if private and key in private:
continue
if public and key not in public:
continue
value = self._serialize(key, field.value)
if value:
data[key] = value
return data
@classmethod
def _serialize(cls, key, value):
print 'Field name: %s' % key
if isinstance(value, (datetime, date)):
print 'Type date'
result = value.isoformat()
elif hasattr(value, '__iter__'):
print 'Type iterable'
result = []
for v in value:
result.append(cls._serialize(key, v))
elif isinstance(value, Serializer):
print 'Type Serializer'
result = value.to_dict()
else:
print 'Type other'
result = value
print 'Result %r\n' % result
return result
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[sqlalchemy] Re: How to jsonify Query result?
The tuples are a variant of python's NamedTuple (sqlalchemy.utils._collections.KeyedTuple) and contain the column names in a `keys` method. You can just write a json adapter that handles instances of KeyedTuple and iterates over their K/V pairs. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
