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JSON Serializable SQLAlchemy Object
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| class JsonSerializableMixin(object): | |
| def __json__(self, request): | |
| """ | |
| Converts all the properties of the object into a dict for use in json. | |
| You can define the following in your class | |
| _json_eager_load : | |
| list of which child classes need to be eagerly loaded. This applies | |
| to one-to-many relationships defined in SQLAlchemy classes. | |
| _base_blacklist : | |
| top level blacklist list of which properties not to include in JSON | |
| _json_blacklist : | |
| blacklist list of which properties not to include in JSON | |
| :param request: Pyramid Request object | |
| :type request: <Request> | |
| :return: dictionary ready to be jsonified | |
| :rtype: <dict> | |
| """ | |
| props = {} | |
| # grab the json_eager_load set, if it exists | |
| # use set for easy 'in' lookups | |
| json_eager_load = set(getattr(self, '_json_eager_load', [])) | |
| # now load the property if it exists | |
| # (does this issue too many SQL statements?) | |
| for prop in json_eager_load: | |
| getattr(self, prop, None) | |
| # we make a copy because the dict will change if the database | |
| # is updated / flushed | |
| options = self.__dict__.copy() | |
| # setup the blacklist | |
| # use set for easy 'in' lookups | |
| blacklist = set(getattr(self, '_base_blacklist', [])) | |
| # extend the base blacklist with the json blacklist | |
| blacklist.update(getattr(self, '_json_blacklist', [])) | |
| for key in options: | |
| # skip blacklisted properties | |
| if key in blacklist: | |
| continue | |
| # do not include private and SQLAlchemy properties | |
| if key.startswith(('__', '_sa_')): | |
| continue | |
| # format and date/datetime/time properties to isoformat | |
| obj = getattr(self, key) | |
| if isinstance(obj, (datetime, date, time)): | |
| props[key] = obj.isoformat() | |
| continue | |
| # get the class property value | |
| attr = getattr(self, key) | |
| # let see if we need to eagerly load it | |
| # this is for SQLAlchemy foreign key fields that | |
| # indicate with one-to-many relationships | |
| if key in json_eager_load and not hasattr(attr, 'pk') and attr: | |
| # jsonify all child objects | |
| props[key] = [x.__json__(request) for x in attr] | |
| continue | |
| # convert all non integer strings to string or if string conversion | |
| # is not possible, convert it to Unicode | |
| if attr and not isinstance(attr, (int, float)): | |
| try: | |
| props[key] = str(attr) | |
| except UnicodeEncodeError: | |
| props[key] = unicode(attr) # .encode('utf-8') | |
| continue | |
| props[key] = attr | |
| return props |
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