<p>I am planning to create a web app that allows users to downgrade their visual studio project files. However, It seems Google App Engine accepts files uploading and flat file storing on the Google Server through <code>db.TextProperty</code> and <code>db.BlobProperty</code>.</p>

<p>I'll be glad anyone can provide code sample (both the client and the server side) on how this can be done.</p>

You can not store files as there is not a traditional file system.  You can only store them in their own DataStore (in a field defined as a
BlobProperty
)
There is an example in the previous link:
```
```
class MyModel(db.Model):
  blob = db.BlobProperty()

obj = MyModel()
obj.blob = db.Blob( file_contents )
```
```