Fix allowing null passwords and for persisting an updated hash; ref #49

sqlalchemy_utils/types/password.py

@@ -4,6 +4,7 @@ from sqlalchemy_utils import ImproperlyConfigured
 from sqlalchemy import types
 from sqlalchemy.dialects import postgresql
 from .scalar_coercible import ScalarCoercible
+from sqlalchemy.ext.mutable import Mutable
 
 passlib = None
 try:
@@ -13,28 +14,62 @@ except ImportError:
     pass
 
 
-class Password(object):
-    def __init__(self, value, context=None):
-        # Store the hash.
-        self.hash = value
+class Password(Mutable, object):
+
+    @classmethod
+    def coerce(cls, key, value):
+        if isinstance(value, Password):
+            return value
+
+        if isinstance(value, (six.string_types, six.binary_type)):
+            return cls(value, secret=True)
+
+        super(Password, cls).coerce(key, value)
+
+    def __init__(self, value, context=None, secret=False):
+        # Store the hash (if it is one).
+        self.hash = value if not secret else None
+
+        # Store the secret if we have one.
+        self.secret = value if secret else None
+
+        # The hash should be bytes.
+        if isinstance(self.hash, six.text_type):
+            self.hash = self.hash.encode('utf8')
 
         # Save weakref of the password context (if we have one)
-        if context is not None:
-            self.context = weakref.proxy(context)
+        self.context = weakref.proxy(context) if context is not None else None
 
     def __eq__(self, value):
+        if self.hash is None or value is None:
+            # Ensure that we don't continue comparison if one of us is None.
+            return self.hash is value
+
         if isinstance(value, Password):
             # Comparing 2 hashes isn't very useful; but this equality
             # method breaks otherwise.
             return value.hash == self.hash
 
+        if self.context is None:
+            # Compare 2 hashes again as we don't know how to validate.
+            return value == self
+
+        if isinstance(value, (six.string_types, six.binary_type)):
             valid, new = self.context.verify_and_update(value, self.hash)
             if valid and new:
                 # New hash was calculated due to various reasons; stored one
                 # wasn't optimal, etc.
                 self.hash = new
+
+                # The hash should be bytes.
+                if isinstance(self.hash, six.text_type):
+                    self.hash = self.hash.encode('utf8')
+                    self.changed()
+
             return valid
 
+        return False
+
     def __ne__(self, value):
         return not (self == value)
 
@@ -143,6 +178,7 @@ class PasswordType(types.TypeDecorator, ScalarCoercible):
             return Password(value, self.context)
 
     def _coerce(self, value):
+
         if value is None:
             return
 
@@ -155,4 +191,12 @@ class PasswordType(types.TypeDecorator, ScalarCoercible):
             # If were given a password object; ensure the context is right.
             value.context = weakref.proxy(self.context)
 
+            # If were given a password secret; encrypt it.
+            if value.secret is not None:
+                value.hash = self.context.encrypt(value.secret).encode('utf8')
+                value.secret = None
+
         return value
+
+
+Password.associate_with(PasswordType)