Read the content of a file
You will probably have to create a library, module, or simple a function Wick does the logic of this, and then call the function from where you want (views).

It's a pretty generic question, without more info is difficult to know what you are trying to achieve, but in similar situations what we use to do is create a separate library or module which is called from cron, for example. 

This library will keep updated a second content type, with the contents of your files, RSS, XML, etc. 

When views saves this content, you'll simply have to link both content types, probably making it faster simply reading contents and leaving the logic to a background process (managed by cron).

But again, maybe you are trying to achieve a different thing.