This is a flow that creates a bot for IRC, and logs all content to a Dropbox account/file of your choice.
To make this work, import the flow to your local node-red instance. From there, you will need to configure the nodes. You will also need the IRC and Dropbox node-red nodes.
-Configuration-
IRC node: Add a new IRC server and choose which channel you would like to record
File (connected to IRC flow): Change "/path/to/filename.txt" to the location where you want the file to be saved.