parhammmm · December 8, 2012 19:20 · Dec 10, 2012 · Dec 10, 2012 · Dec 8, 2012 · Dec 8, 2012
diff --git a/models.py b/models.py
@@ -54,7 +54,7 @@ def __init__(self, *args, **kwargs):
         )   
 
     def _encrypted_pk(self):
-        encryption_obj = DES.new(self.model.PK_SECRET_KEY) # This 8 character secret key should be changed!
+        encryption_obj = DES.new(self.PK_SECRET_KEY) # This 8 character secret key should be changed!
         return base36encode(struct.unpack('<Q', encryption_obj.encrypt(
             str(struct.pack('<Q', self.pk))
         ))[0])

diff --git a/models.py b/models.py
@@ -54,7 +54,7 @@ def __init__(self, *args, **kwargs):
         )   
 
     def _encrypted_pk(self):
-        encryption_obj = DES.new(self.PK_SECRET_KEY) # This 8 character secret key should be changed!
+        encryption_obj = DES.new(self.model.PK_SECRET_KEY) # This 8 character secret key should be changed!
         return base36encode(struct.unpack('<Q', encryption_obj.encrypt(
             str(struct.pack('<Q', self.pk))
         ))[0])

diff --git a/models.py b/models.py
@@ -70,7 +70,7 @@ class ExampleModelManager(EncryptedPKModelManager):
 
 
 class ExampleModel(EncryptedPKModel):
-    PK_ENCRYPTION_KEY = '8charkey'
+    PK_SECRET_KEY = '8charkey'
     objects = ExampleModelManager()
     example_field = models.CharField(max_length=32)
 

diff --git a/models.py b/models.py
@@ -27,7 +27,7 @@ def base36decode(numstr):
     return int(numstr,36)
 
 
-class EncryptedPKManager(models.Manager):
+class EncryptedPKModelManager(models.Manager):
     """This manager allows models to be identified based on their encrypted_pk value."""
 
     def get(self, *args, **kwargs):

diff --git a/models.py b/models.py
@@ -6,7 +6,6 @@
 from Crypto.Cipher import DES
 from django.db import models
 
-
 def base36encode(number):
     """Encode number to string of alphanumeric characters (0 to z). (Code taken from Wikipedia)."""
     if not isinstance(number, (int, long)):
@@ -28,32 +27,35 @@ def base36decode(numstr):
     return int(numstr,36)
 
 
-class EncryptedPKModelManager(models.Manager):
+class EncryptedPKManager(models.Manager):
     """This manager allows models to be identified based on their encrypted_pk value."""
+
     def get(self, *args, **kwargs):
         encrypted_pk = kwargs.pop('encrypted_pk', None)
         if encrypted_pk:
             # If found, decrypt encrypted_pk argument and set pk argument to the appropriate value
-            kwargs['pk'] = struct.unpack('<Q', self.model.encryption_obj.decrypt(
+            encryption_obj = DES.new(self.model.PK_SECRET_KEY) # This 8 character secret key should be changed!
+            kwargs['pk'] = struct.unpack('<Q', encryption_obj.decrypt(
                 struct.pack('<Q', base36decode(encrypted_pk))
             ))[0]
-        return super(EncryptedPKModelManager, self).get(*args, **kwargs)
+
+        return super(EncryptedPKManager, self).get(*args, **kwargs)
 
 
 class EncryptedPKModel(models.Model):
     """Adds encrypted_pk property to children which returns the encrypted value of the primary key."""
-    encryption_obj = DES.new('8charkey') # This 8 character secret key should be changed!
 
     def __init__(self, *args, **kwargs):
         super(EncryptedPKModel, self).__init__(*args, **kwargs)
         setattr(
             self.__class__,
             "encrypted_%s" % (self._meta.pk.name,),
             property(self.__class__._encrypted_pk)
-        )
+        )   
 
     def _encrypted_pk(self):
-        return base36encode(struct.unpack('<Q', self.encryption_obj.encrypt(
+        encryption_obj = DES.new(self.PK_SECRET_KEY) # This 8 character secret key should be changed!
+        return base36encode(struct.unpack('<Q', encryption_obj.encrypt(
             str(struct.pack('<Q', self.pk))
         ))[0])
 
@@ -68,11 +70,12 @@ class ExampleModelManager(EncryptedPKModelManager):
 
 
 class ExampleModel(EncryptedPKModel):
+    PK_ENCRYPTION_KEY = '8charkey'
     objects = ExampleModelManager()
     example_field = models.CharField(max_length=32)
 
 
 # Example usage:
 # example_instance = ExampleModel.objects.get(pk=1)
 # url_pk = example_instance.encrypted_pk
-# ExampleModel.objects.get(encrypted_pk=url_pk)
+# ExampleModel.objects.get(encrypted_pk=url_pk)
diff --git a/models.py b/models.py
@@ -8,7 +8,7 @@
 
 
 def base36encode(number):
-    """Encode number to string of characters in the range 0 9 and a to z. (Code taken from Wikipedia)."""
+    """Encode number to string of alphanumeric characters (0 to z). (Code taken from Wikipedia)."""
     if not isinstance(number, (int, long)):
         raise TypeError('number must be an integer')
     if number < 0:

diff --git a/models.py b/models.py
@@ -33,7 +33,7 @@ class EncryptedPKModelManager(models.Manager):
     def get(self, *args, **kwargs):
         encrypted_pk = kwargs.pop('encrypted_pk', None)
         if encrypted_pk:
-            # If found, decrypt encrypted_pk keyword argument and set pk argument to the appropriate value
+            # If found, decrypt encrypted_pk argument and set pk argument to the appropriate value
             kwargs['pk'] = struct.unpack('<Q', self.model.encryption_obj.decrypt(
                 struct.pack('<Q', base36decode(encrypted_pk))
             ))[0]

diff --git a/models.py b/models.py
@@ -1,3 +1,4 @@
+# This code is under the MIT license.
 # Inspired by this StackOverflow question:
 http://stackoverflow.com/questions/3295405/creating-django-objects-with-a-random-primary-key
 

diff --git a/models.py b/models.py
@@ -1,4 +1,5 @@
-# Inspired by this StackOverflow question: http://stackoverflow.com/questions/3295405/creating-django-objects-with-a-random-primary-key
+# Inspired by this StackOverflow question:
+http://stackoverflow.com/questions/3295405/creating-django-objects-with-a-random-primary-key
 
 import struct
 from Crypto.Cipher import DES

diff --git a/models.py b/models.py
@@ -1,3 +1,5 @@
+# Inspired by this StackOverflow question: http://stackoverflow.com/questions/3295405/creating-django-objects-with-a-random-primary-key
+
 import struct
 from Crypto.Cipher import DES
 from django.db import models

diff --git a/models.py b/models.py
@@ -29,21 +29,29 @@ class EncryptedPKModelManager(models.Manager):
     def get(self, *args, **kwargs):
         encrypted_pk = kwargs.pop('encrypted_pk', None)
         if encrypted_pk:
-            # If the encrypted_pk keyword argument was found, decrypt it and set the pk argument to the appropriate value
-            kwargs['pk'] = struct.unpack('<Q', self.model.encryption_obj.decrypt(struct.pack('<Q', base36decode(encrypted_pk))))[0]
+            # If found, decrypt encrypted_pk keyword argument and set pk argument to the appropriate value
+            kwargs['pk'] = struct.unpack('<Q', self.model.encryption_obj.decrypt(
+                struct.pack('<Q', base36decode(encrypted_pk))
+            ))[0]
         return super(EncryptedPKModelManager, self).get(*args, **kwargs)
 
 
 class EncryptedPKModel(models.Model):
-    """Models that inherit from this class will have an encrypted_pk property that returns the encrypted value of the primary key."""
+    """Adds encrypted_pk property to children which returns the encrypted value of the primary key."""
     encryption_obj = DES.new('8charkey') # This 8 character secret key should be changed!
 
     def __init__(self, *args, **kwargs):
         super(EncryptedPKModel, self).__init__(*args, **kwargs)
-        setattr(self.__class__, "encrypted_%s" % (self._meta.pk.name,), property(self.__class__._encrypted_pk))
+        setattr(
+            self.__class__,
+            "encrypted_%s" % (self._meta.pk.name,),
+            property(self.__class__._encrypted_pk)
+        )
 
     def _encrypted_pk(self):
-        return base36encode(struct.unpack('<Q', self.encryption_obj.encrypt(str(struct.pack('<Q', self.pk))))[0])
+        return base36encode(struct.unpack('<Q', self.encryption_obj.encrypt(
+            str(struct.pack('<Q', self.pk))
+        ))[0])
 
     encrypted_pk = property(_encrypted_pk)
 

diff --git a/models.py b/models.py
@@ -1,3 +1,5 @@
+# Inspired by this StackOverflow question: http://stackoverflow.com/questions/3295405/creating-django-objects-with-a-random-primary-key
+
 import struct
 from Crypto.Cipher import DES
 from django.db import models

diff --git a/models.py b/models.py
@@ -37,6 +37,11 @@ def get(self, *args, **kwargs):
 class EncryptedPKModel(models.Model):
     """Models that inherit from this class will have an encrypted_pk property that returns the encrypted value of the primary key."""
     encryption_obj = DES.new('8charkey') # This 8 character secret key should be changed!
+
+    def __init__(self, *args, **kwargs):
+        super(EncryptedPKModel, self).__init__(*args, **kwargs)
+        setattr(self.__class__, "encrypted_%s" % (self._meta.pk.name,), property(self.__class__._encrypted_pk))
+
     def _encrypted_pk(self):
         return base36encode(struct.unpack('<Q', self.encryption_obj.encrypt(str(struct.pack('<Q', self.pk))))[0])
 

diff --git a/models.py b/models.py
@@ -34,20 +34,23 @@ def get(self, *args, **kwargs):
         return super(EncryptedPKModelManager, self).get(*args, **kwargs)
 
 
-class EncryptedPKModel:
+class EncryptedPKModel(models.Model):
     """Models that inherit from this class will have an encrypted_pk property that returns the encrypted value of the primary key."""
     encryption_obj = DES.new('8charkey') # This 8 character secret key should be changed!
     def _encrypted_pk(self):
         return base36encode(struct.unpack('<Q', self.encryption_obj.encrypt(str(struct.pack('<Q', self.pk))))[0])
 
     encrypted_pk = property(_encrypted_pk)
 
+    class Meta:
+        abstract = True
+
 
 class ExampleModelManager(EncryptedPKModelManager):
     pass
 
 
-class ExampleModel(models.Model,EncryptedPKModel):
+class ExampleModel(EncryptedPKModel):
     objects = ExampleModelManager()
     example_field = models.CharField(max_length=32)
 

diff --git a/models.py b/models.py
@@ -0,0 +1,58 @@
+import struct
+from Crypto.Cipher import DES
+from django.db import models
+
+
+def base36encode(number):
+    """Encode number to string of characters in the range 0 9 and a to z. (Code taken from Wikipedia)."""
+    if not isinstance(number, (int, long)):
+        raise TypeError('number must be an integer')
+    if number < 0:
+        raise ValueError('number must be positive')
+
+    alphabet = '0123456789abcdefghijklmnopqrstuvwxyz'
+    base36 = ''
+    while number:
+        number, i = divmod(number, 36)
+        base36 = alphabet[i] + base36
+
+    return base36 or alphabet[0]
+
+
+def base36decode(numstr):
+    """Convert a base-36 string (made of alphanumeric characters) to its numeric value."""
+    return int(numstr,36)
+
+
+class EncryptedPKModelManager(models.Manager):
+    """This manager allows models to be identified based on their encrypted_pk value."""
+    def get(self, *args, **kwargs):
+        encrypted_pk = kwargs.pop('encrypted_pk', None)
+        if encrypted_pk:
+            # If the encrypted_pk keyword argument was found, decrypt it and set the pk argument to the appropriate value
+            kwargs['pk'] = struct.unpack('<Q', self.model.encryption_obj.decrypt(struct.pack('<Q', base36decode(encrypted_pk))))[0]
+        return super(EncryptedPKModelManager, self).get(*args, **kwargs)
+
+
+class EncryptedPKModel:
+    """Models that inherit from this class will have an encrypted_pk property that returns the encrypted value of the primary key."""
+    encryption_obj = DES.new('8charkey') # This 8 character secret key should be changed!
+    def _encrypted_pk(self):
+        return base36encode(struct.unpack('<Q', self.encryption_obj.encrypt(str(struct.pack('<Q', self.pk))))[0])
+
+    encrypted_pk = property(_encrypted_pk)
+
+
+class ExampleModelManager(EncryptedPKModelManager):
+    pass
+
+
+class ExampleModel(models.Model,EncryptedPKModel):
+    objects = ExampleModelManager()
+    example_field = models.CharField(max_length=32)
+
+
+# Example usage:
+# example_instance = ExampleModel.objects.get(pk=1)
+# url_pk = example_instance.encrypted_pk
+# ExampleModel.objects.get(encrypted_pk=url_pk)