Adding a JSON Datatype

eav/forms.py

@@ -8,6 +8,12 @@ from django.forms import (BooleanField, CharField, ChoiceField, DateTimeField,
 from django.utils.translation import ugettext_lazy as _
 
 
+try:
+    from django.forms import JSONField
+except:
+    JSONField = CharField
+
+
 class BaseDynamicEntityForm(ModelForm):
     """
     ``ModelForm`` for entity with support for EAV attributes. Form fields are
@@ -28,6 +34,7 @@ class BaseDynamicEntityForm(ModelForm):
     int    DateTimeField
     bool   BooleanField
     enum   ChoiceField
+    json   JSONField
     =====  =============
     """
     FIELD_CLASSES = {
@@ -37,6 +44,7 @@ class BaseDynamicEntityForm(ModelForm):
         'date': DateTimeField,
         'bool': BooleanField,
         'enum': ChoiceField,
+        'json': JSONField,
     }
 
     def __init__(self, data=None, *args, **kwargs):

eav/migrations/0003_auto_20210404_2209.py

@@ -0,0 +1,29 @@
+# Generated by Django 3.1.6 on 2021-04-04 22:09
+
+from django.db import migrations
+import eav.fields
+import django.core.serializers.json
+try:
+    from django.db.models import JSONField
+except:
+    from django.contrib.postgres.fields import JSONField
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('eav', '0002_add_entity_ct_field'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='value',
+            name='value_json',
+            field=JSONField(blank=True, default=dict, encoder=django.core.serializers.json.DjangoJSONEncoder, null=True),
+        ),
+        migrations.AlterField(
+            model_name='attribute',
+            name='datatype',
+            field=eav.fields.EavDatatypeField(choices=[('text', 'Text'), ('date', 'Date'), ('float', 'Float'), ('int', 'Integer'), ('bool', 'True / False'), ('object', 'Django Object'), ('enum', 'Multiple Choice'), ('json', 'JSON Object')], max_length=6, verbose_name='Data Type'),
+        ),
+    ]

eav/models.py

@@ -19,6 +19,16 @@ from django.db.models.base import ModelBase
 from django.utils import timezone
 from django.utils.translation import ugettext_lazy as _
 
+from django.core.serializers.json import DjangoJSONEncoder
+if hasattr(models, "JSONField"):
+    JSONField = models.JSONField
+else:
+   try:
+       from django.contrib.postgres.fields import JSONField
+   except:
+       JSONField = models.TextField
+
+
 from .validators import (
     validate_text,
     validate_float,
@@ -26,7 +36,8 @@ from .validators import (
     validate_date,
     validate_bool,
     validate_object,
-    validate_enum
+    validate_enum,
+    validate_json
 )
 from .exceptions import IllegalAssignmentException
 from .fields import EavDatatypeField, EavSlugField
@@ -107,6 +118,7 @@ class Attribute(models.Model):
         * bool (TYPE_BOOLEAN)
         * object (TYPE_OBJECT)
         * enum (TYPE_ENUM)
+        * json (TYPE_JSON)
 
     Examples::
 
@@ -138,6 +150,7 @@ class Attribute(models.Model):
     TYPE_BOOLEAN = 'bool'
     TYPE_OBJECT  = 'object'
     TYPE_ENUM    = 'enum'
+    TYPE_JSON    = 'json'
 
     DATATYPE_CHOICES = (
         (TYPE_TEXT,    _('Text')),
@@ -147,6 +160,7 @@ class Attribute(models.Model):
         (TYPE_BOOLEAN, _('True / False')),
         (TYPE_OBJECT,  _('Django Object')),
         (TYPE_ENUM,    _('Multiple Choice')),
+        (TYPE_JSON,    _('JSON Object')),
     )
 
     # Core attributes
@@ -248,6 +262,7 @@ class Attribute(models.Model):
             'bool':   validate_bool,
             'object': validate_object,
             'enum':   validate_enum,
+            'json':   validate_json,
         }
 
         return [DATATYPE_VALIDATORS[self.datatype]]
@@ -382,6 +397,7 @@ class Value(models.Model):
     value_int   = models.IntegerField(blank = True, null = True)
     value_date  = models.DateTimeField(blank = True, null = True)
     value_bool  = models.NullBooleanField(blank = True, null = True)
+    value_json  = JSONField(default=dict, encoder=DjangoJSONEncoder, blank = True, null = True)
 
     value_enum  = models.ForeignKey(
         EnumValue,

eav/validators.py

@@ -10,6 +10,7 @@ These validators are called by the
 :class:`~eav.models.Attribute` model.
 """
 
+import json
 import datetime
 
 from django.core.exceptions import ValidationError
@@ -83,3 +84,16 @@ def validate_enum(value):
 
     if isinstance(value, EnumValue) and not value.pk:
         raise ValidationError(_(u"EnumValue has not been saved yet"))
+
+
+def validate_json(value):
+    """
+    Raises ``ValidationError`` unless *value* can be cast as an ``json object`` (a dict)
+    """
+    try:
+        if isinstance(value, str):
+            value = json.loads(value)
+        if not isinstance(value, dict):
+            raise ValidationError(_(u"Must be a JSON Serializable object"))
+    except ValueError:
+        raise ValidationError(_(u"Must be a JSON Serializable object"))

tests/data_validation.py

@@ -21,6 +21,7 @@ class DataValidation(TestCase):
         Attribute.objects.create(name='City', datatype=Attribute.TYPE_TEXT)
         Attribute.objects.create(name='Pregnant?', datatype=Attribute.TYPE_BOOLEAN)
         Attribute.objects.create(name='User', datatype=Attribute.TYPE_OBJECT)
+        Attribute.objects.create(name='Extra', datatype=Attribute.TYPE_JSON)
 
     def tearDown(self):
         eav.unregister(Patient)
@@ -186,3 +187,11 @@ class DataValidation(TestCase):
         ynu.values.add(unkown)
         a = Attribute(name='color', datatype=Attribute.TYPE_TEXT, enum_group=ynu)
         self.assertRaises(ValidationError, a.save)
+
+    def test_json_validation(self):
+        p = Patient.objects.create(name='Joe')
+        p.eav.extra = 5
+        self.assertRaises(ValidationError, p.save)
+        p.eav.extra = {"eyes": "blue", "hair": "brown"}
+        p.save()
+        self.assertEqual(Patient.objects.get(pk=p.pk).eav.extra.get("eyes", ""), "blue")

tests/queries.py

@@ -20,6 +20,7 @@ class Queries(TestCase):
         Attribute.objects.create(name='weight', datatype=Attribute.TYPE_FLOAT)
         Attribute.objects.create(name='city', datatype=Attribute.TYPE_TEXT)
         Attribute.objects.create(name='country', datatype=Attribute.TYPE_TEXT)
+        Attribute.objects.create(name='extras', datatype=Attribute.TYPE_JSON)
 
         self.yes = EnumValue.objects.create(value='yes')
         self.no = EnumValue.objects.create(value='no')
@@ -41,12 +42,12 @@ class Queries(TestCase):
         no = self.no
 
         data = [
-            # Name,    age, fever, city,       country.
-            ['Anne',   3,   no,    'New York', 'USA'],
-            ['Bob',    15,  no,    'Bamako',   'Mali'],
-            ['Cyrill', 15,  yes,   'Kisumu',   'Kenya'],
-            ['Daniel', 3,   no,    'Nice',     'France'],
-            ['Eugene', 2,   yes,   'France',   'Nice']
+            # Name,    age, fever, city,       country,   extras
+            ['Anne',   3,   no,    'New York', 'USA',     {"chills": "yes"}],
+            ['Bob',    15,  no,    'Bamako',   'Mali',    {}],
+            ['Cyrill', 15,  yes,   'Kisumu',   'Kenya',   {"chills": "yes", "headache": "no"}],
+            ['Daniel', 3,   no,    'Nice',     'France',  {"headache": "yes"}],
+            ['Eugene', 2,   yes,   'France',   'Nice',    {"chills": "no", "headache": "yes"}]
         ]
 
         for row in data:
@@ -55,7 +56,8 @@ class Queries(TestCase):
                 eav__age=row[1],
                 eav__fever=row[2],
                 eav__city=row[3],
-                eav__country=row[4]
+                eav__country=row[4],
+                eav__extras=row[5]
             )
 
     def test_get_or_create_with_eav(self):
@@ -81,7 +83,7 @@ class Queries(TestCase):
 
         # Check number of objects in DB.
         self.assertEqual(Patient.objects.count(), 5)
-        self.assertEqual(Value.objects.count(), 20)
+        self.assertEqual(Value.objects.count(), 25)
 
         # Nobody
         q1 = Q(eav__fever=self.yes) & Q(eav__fever=self.no)
@@ -149,6 +151,38 @@ class Queries(TestCase):
         p = Patient.objects.filter(q1)
         self.assertEqual(p.count(), 1)
 
+        # Extras: Chills
+        # Without
+        q1 = Q(eav__extras__has_key="chills")
+        p = Patient.objects.exclude(q1)
+        self.assertEqual(p.count(), 2)
+
+        # With
+        q1 = Q(eav__extras__has_key="chills")
+        p = Patient.objects.filter(q1)
+        self.assertEqual(p.count(), 3)
+
+        # No chills
+        q1 = Q(eav__extras__chills="no")
+        p = Patient.objects.filter(q1)
+        self.assertEqual(p.count(), 1)
+
+        # Has chills
+        q1 = Q(eav__extras__chills="yes")
+        p = Patient.objects.filter(q1)
+        self.assertEqual(p.count(), 2)
+
+        # Extras: Empty
+        # Yes
+        q1 = Q(eav__extras={})
+        p = Patient.objects.filter(q1)
+        self.assertEqual(p.count(), 1)
+
+        # No
+        q1 = Q(eav__extras={})
+        p = Patient.objects.exclude(q1)
+        self.assertEqual(p.count(), 4)
+
     def _order(self, ordering):
         query = Patient.objects.all().order_by(*ordering)
         return list(query.values_list('name', flat=True))