Merge pull request #2 from feliperyan/master

LocalStorageFileField - thanks @feliperyan

Author: rozza

fields/fields.py

@@ -1,6 +1,18 @@
 from datetime import timedelta
 from mongoengine.base import BaseField
 
+import os
+import datetime
+
+from mongoengine.python_support import str_types
+from django.db.models.fields.files import FieldFile
+from django.core.files.base import File
+from django.core.files.storage import default_storage
+
+from mongoengine.connection import get_db, DEFAULT_CONNECTION_NAME
+from django.utils.encoding import force_text
+
+
 class TimedeltaField(BaseField):
     """A timedelta field.
 
@@ -38,3 +50,83 @@ def total_seconds(value):
             return (value.days * 24 * 3600) + \
                    (value.seconds) + \
                    (value.microseconds / 1000000.0)
+
+
+class LocalStorageFileField(BaseField):
+    
+    proxy_class = FieldFile
+
+    def __init__(self,
+                 db_alias=DEFAULT_CONNECTION_NAME, 
+                 name=None,
+                 upload_to='',
+                 storage=None,
+                 **kwargs):
+
+        self.db_alias = db_alias
+        self.storage = storage or default_storage
+        self.upload_to = upload_to
+
+        if callable(upload_to):
+            self.generate_filename = upload_to
+
+        super(DJFileField, self).__init__(**kwargs)
+
+
+    def __get__(self, instance, owner):
+        # Lots of information on whats going on here can be found
+        # on Django's FieldFile implementation, go over to GitHub to
+        # read it.
+        file = instance._data.get(self.name)
+
+        if isinstance(file, str_types) or file is None:
+            attr = self.proxy_class(instance, self, file)
+            instance._data[self.name] = attr
+
+        elif isinstance(file, File) and not isinstance(file, FieldFile):
+            file_copy = self.proxy_class(instance, self, file.name)
+            file_copy.file = file
+            file_copy._committed = False
+            instance._data[self.name] = file_copy
+
+        elif isinstance(file, FieldFile) and not hasattr(file, 'field'):
+            file.instance = instance
+            file.field = self
+            file.storage = self.storage
+ 
+        return instance._data[self.name]
+
+
+    def __set__(self, instance, value):
+        instance._data[self.name] = value
+
+
+    def get_directory_name(self):
+        return os.path.normpath(force_text(datetime.datetime.now().strftime(self.upload_to)))
+
+
+    def get_filename(self, filename):
+        return os.path.normpath(self.storage.get_valid_name(os.path.basename(filename)))
+
+
+    def generate_filename(self, instance, filename):
+        return os.path.join(self.get_directory_name(), self.get_filename(filename))
+
+
+    def to_mongo(self, value):
+    # Store the path in MongoDB
+    # I also used this bit to actually save the file to disk.
+    # The value I'm getting here is a FileFiled and it all looks ok.
+
+        if not value._committed and value is not None:
+            value.save(value.name, value)
+            return value.path
+
+        return value.name    
+
+
+    def to_python(self, value):
+        eu = self
+        return eu.proxy_class(eu.owner_document, eu, value)
+
+