Add SQLite support.

Author: carljm

README.rst

@@ -19,8 +19,8 @@ Django model fields whose value is transparently encrypted using the `Fernet
 recipe`_ from the `cryptography`_ library.
 
 ``django-fernet-fields`` supports `Django`_ 1.8.2 and later on Python 2.7, 3.3,
-3.4, pypy, and pypy3. Currently PostgreSQL is the only supported database, but
-other backends could easily be supported as well.
+3.4, pypy, and pypy3. Currently PostgreSQL and SQLite are the only supported
+databases, but support for other backends could easily be added.
 
 .. _Django: http://www.djangoproject.com/
 .. _Fernet recipe: https://cryptography.io/en/latest/fernet/

doc/index.rst

@@ -14,8 +14,8 @@ Prerequisites
 ``django-fernet-fields`` supports `Django`_ 1.8.2 and later on Python 2.7, 3.3,
 3.4, pypy, and pypy3.
 
-PostgreSQL is currently the only database with built-in support; support for
-other database backends should be easy to add.
+PostgreSQL and SQLite are currently the only databases with built-in support;
+support for other database backends should be easy to add.
 
 .. _Django: http://www.djangoproject.com/
 

fernet_fields/fields.py

@@ -64,9 +64,17 @@ def fernet(self):
         return MultiFernet([Fernet(k) for k in self.fernet_keys])
 
     def db_type(self, connection):
+        # PostgreSQL and SQLite both support the BYTEA type.
         return 'bytea'
 
-    def get_prep_value(self, value):
+    def get_internal_type(self):
+        """Prevent Django from doing type conversions on encrypted data."""
+        return None
+
+    def get_db_prep_value(self, *args, **kwargs):
+        value = super(
+            EncryptedFieldMixin, self
+        ).get_db_prep_value(*args, **kwargs)
         if value is not None:
             return self.fernet.encrypt(force_bytes(value))
 

fernet_fields/test/settings/__init__.py

@@ -4,16 +4,6 @@
     from psycopg2cffi import compat
     compat.register()
 
-DATABASES = {
-    'default': {
-        'ENGINE': 'django.db.backends.postgresql_psycopg2',
-        'NAME': 'djftest',
-        'TEST': {
-            'NAME': 'djftest',
-        },
-    },
-}
-
 INSTALLED_APPS = [
     'fernet_fields.test'
 ]

fernet_fields/test/settings.py renamed to fernet_fields/test/settings/base.py

@@ -0,0 +1,11 @@
+from .base import *
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.postgresql_psycopg2',
+        'NAME': 'djftest',
+        'TEST': {
+            'NAME': 'djftest',
+        },
+    },
+}

fernet_fields/test/settings/pg.py

@@ -0,0 +1,16 @@
+from .base import *
+
+import os
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+DB = os.path.join(HERE, 'testdb.sqlite')
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': DB,
+        'TEST': {
+            'NAME': DB,
+        },
+    },
+}

fernet_fields/test/settings/sqlite.py

@@ -5,6 +5,6 @@
 import sys
 
 os.environ.setdefault(
-    'DJANGO_SETTINGS_MODULE', 'fernet_fields.test.settings')
+    'DJANGO_SETTINGS_MODULE', 'fernet_fields.test.settings.sqlite')
 
 sys.exit(pytest.main())

runtests.py

@@ -1,5 +1,5 @@
 [tox]
-envlist = py{27,33,34,py,py3}-django{18,trunk},flake8,docs
+envlist = py{27,33,34,py,py3}-django{18,trunk}-{pg,sqlite},flake8,docs
 
 [testenv]
 deps =
@@ -9,8 +9,11 @@ deps =
     coverage==3.7.1
     django18: Django>=1.8,<1.9
     djangotrunk: https://github.com/django/django/tarball/master
-    py{26,27,33,34}: psycopg2==2.6
-    {pypy,pypy3}: psycopg2cffi==2.6.1
+    py{26,27,33,34}-pg: psycopg2==2.6
+    {pypy,pypy3}-pg: psycopg2cffi==2.6.1
+setenv =
+    sqlite: DJANGO_SETTINGS_MODULE = fernet_fields.test.settings.sqlite
+    pg: DJANGO_SETTINGS_MODULE = fernet_fields.test.settings.pg
 commands =
     coverage run -a runtests.py fernet_fields/test --tb short