I'm planning a server application that will handle files uploaded via FTP. The application must parse text documents that it receives and write them to a database (most likely a document-oriented database like Mongo). And the application must also relay all large binary files it receives to Amazon S3 for storage and hosting.
I'd like to manage all aspects of the FTP server programmatically. For example, when a user registers via a web page the application should be able to create the user account in the database and provision a directory on the server for receiving files. I'm using a Linux server but am otherwise open to considering any programming language or framework.
I'm open to anything that can run on a Linux box.