There are many usefull CSV-Importer, but i didn't found one with a "Preview" of the Data to import. So start to make my own: but i stuck on HOW to organise all this in a nice cake-like way (just started programming)
Functions
This importer should be/have/can:
Problem
how should a organise this to offer this as a tool, which can easy be accessed by an user from everywhere (where i added this importer)
i don't need code :) it's all about how to organise this.
The official Datasource repository contains a CSV Datasource https://github.com/cakephp/datasources/tree/2.0/
Doing this in a component is wrong in the MVC pattern. Data processing is a model task for obvious reasons like re-usability in a shell. And models are easier to unit test.
I don't understand how you intend to use this in every controller. If you need to display the uploaded CSV as a table on every page then simply do a requestAction() simply fetch the CSV data using the datasource I've told you from the model where needed and set it to the view.