I need to be notified and perform other tasks when a file is uploaded onto my server. Is there any method/system call that will be triggered or anything that i can hook onto ? I'm using vsftpd as my ftp server.
You can approach this by using something more generic than a FTP hook (which will also allow it to scale if the users uses SCP, SFTP or even SSH using a text editor): inotify.
There are many languages that support this, but here's a Python API: https://github.com/seb-m/pyinotify/wiki
This would allow you to watch a directory, and when it changes, act on that information.
There is also Python Watchdog: http://code.google.com/p/python-watchdog