From c78fcefe48fee0da9c97f41277f3653ccbfa3d94 Mon Sep 17 00:00:00 2001
From: Tanner Prestegard <tanner.prestegard@ligo.org>
Date: Tue, 3 Apr 2018 07:49:01 -0500
Subject: [PATCH] adding a ModelToDict mixin which can be used to translate a
model instance into a dictionary
---
gracedb/core/models.py | 87 +++++++++++++++++++++++++++++++
gracedb/core/tests/__init__.py | 0
gracedb/core/tests/test_models.py | 4 ++
3 files changed, 91 insertions(+)
create mode 100644 gracedb/core/tests/__init__.py
create mode 100644 gracedb/core/tests/test_models.py
diff --git a/gracedb/core/models.py b/gracedb/core/models.py
index 26df59fd4..d9397a97a 100644
--- a/gracedb/core/models.py
+++ b/gracedb/core/models.py
@@ -1,7 +1,11 @@
from django.contrib.auth import get_user_model
from django.db import models, connection
+from django.utils.translation import ugettext_lazy as _
+from django.forms.models import model_to_dict
+from django.db.models import QuerySet
import re
+from collections import OrderedDict
UserModel = get_user_model()
@@ -166,3 +170,86 @@ class m2mThroughBase(models.Model):
class Meta:
abstract = True
+
+
+class ModelToDictMixin(object):
+ """
+ Defines a to_dict() method which deserializes a model object to
+ a dictionary. Allows the addition of keys which are not directly attached
+ to the model and whose values are customizable.
+
+ Default configuration for the dict is provided by the
+ default_dict_mapping() method.
+
+ The update_dict_mapping() method is used to override parts of the
+ default mapping. Should not need to be customized, since to_dict() passes
+ kwargs to it which it should be able to handle.
+ """
+ QS_KEY = 'queryset'
+ QS_PROP_KEY = 'object_property'
+
+ def to_dict(self, **kwargs):
+ """
+ Usage:
+ object.to_dict()
+ object.to_dict(**{'creator': object.creator.pk})
+ object.to_dict(**{'comments': {'object_property': 'pk'}})
+ """
+ dict_mapping = self.default_dict_mapping()
+ dict_mapping = self._update_dict_mapping(dict_mapping, **kwargs)
+ if not dict_mapping:
+ return model_to_dict(self)
+
+ out_dict = OrderedDict()
+ for k,v in dict_mapping.iteritems():
+ if isinstance(v, dict):
+ if not (v.has_key(self.QS_KEY) and
+ v.has_key(self.QS_PROP_KEY)):
+ raise KeyError(_('Must specify {qs_key} and {qs_prop_key} '
+ 'when mapping model queryset "fields" to dict'))
+
+ queryset = v[self.QS_KEY]
+ prop = v[self.QS_PROP_KEY]
+ if prop.endswith('()'):
+ prop = prop[:-2]
+ if callable(getattr(queryset.model, prop)):
+ value = [getattr(obj, prop)() for obj in queryset]
+ else:
+ value = [getattr(obj, prop) for obj in queryset]
+ else:
+ value = v
+ out_dict[k] = value
+
+ return out_dict
+
+ def _update_dict_mapping(self, dict_mapping, **kwargs):
+ for k,v in kwargs.iteritems():
+ if isinstance(v, dict):
+ if not dict_mapping.has_key(kw):
+ dict_mapping[kw] = {}
+ for k2,v2 in v.iteritems():
+ dict_mapping[k][k2] = v2
+ else:
+ dict_mapping[k] = v
+
+ return dict_mapping
+
+ def default_dict_mapping(self):
+ """
+ Defines a schema for mapping model fields or related object fields
+ to a dictionary. Cases where a field returns multiple objects (like
+ m2m or reverse foreign key relationships) should be provided as a dict
+ which has the 'queryset' and 'object_property' (REQUIRED).
+
+ Example:
+ mapping = {
+ 'creator': self.creator.username,
+ 'comments': {
+ self.QS_KEY: self.comment_set.all(),
+ self.QS_PROP_KEY: 'message',
+ },
+ }
+
+ This method should be overridden by classes which use this mixin.
+ """
+ return {}
diff --git a/gracedb/core/tests/__init__.py b/gracedb/core/tests/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/gracedb/core/tests/test_models.py b/gracedb/core/tests/test_models.py
new file mode 100644
index 000000000..d1c987dbf
--- /dev/null
+++ b/gracedb/core/tests/test_models.py
@@ -0,0 +1,4 @@
+from django.test import TestCase
+
+class TestModelToDictMixin(TestCase):
+ pass
--
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