我已经搜索了很长时间没有成功。我的项目没有使用 Django,有没有一种简单的方法可以将 App Engine 模型(google.appengine.ext.db.Model)序列化为 JSON,还是我需要编写自己的序列化程序?
型号:
class Photo(db.Model):
filename = db.StringProperty()
title = db.StringProperty()
description = db.StringProperty(multiline=True)
date_taken = db.DateTimeProperty()
date_uploaded = db.DateTimeProperty(auto_now_add=True)
album = db.ReferenceProperty(Album, collection_name='photo')
最佳答案
一个简单的递归函数可用于将实体(和任何引用对象)转换为嵌套字典,该字典可以传递给 simplejson
:
import datetime
import time
SIMPLE_TYPES = (int, long, float, bool, dict, basestring, list)
def to_dict(model):
output = {}
for key, prop in model.properties().iteritems():
value = getattr(model, key)
if value is None or isinstance(value, SIMPLE_TYPES):
output[key] = value
elif isinstance(value, datetime.date):
# Convert date/datetime to MILLISECONDS-since-epoch (JS "new Date()").
ms = time.mktime(value.utctimetuple()) * 1000
ms += getattr(value, 'microseconds', 0) / 1000
output[key] = int(ms)
elif isinstance(value, db.GeoPt):
output[key] = {'lat': value.lat, 'lon': value.lon}
elif isinstance(value, db.Model):
output[key] = to_dict(value)
else:
raise ValueError('cannot encode ' + repr(prop))
return output
https://stackoverflow.com/questions/1531501/