Core API

3.9. Various examples

3.9.1. Introduction

The follow pages will present some examples of how you can use the APIs of core libraries. Remember, ultimately the source is the documentation and the only point here is to show examples. Whenever you would like to use core features that are not shown here you should search in the core and system extensions for implementations that can work as an example for you.

Debugging with debug()

A very common tool used by TYPO3 developers is the debug() function. It basically prints out the content of a variable in a nicely formatted table. There are extensions available which extends the view from the debug() function to something more fancy. Here I will just present the basic version.

Use the debug() function whenever you want to look "inside" an array or parameters passed to a user processing function. Usually it makes it very easy to understand the parameters. For instance, lets say you call a script with the GET parameter string "?id=123&test[key]=A&test[key2]=B". How will the GET vars look to your application inside? Well, using the debug function makes that easy:

  debug(t3lib_div::_GET(),'GET variables:');

The output in the browser will look like:

 

Notice that the debug() function is a wrapper for t3lib_div::debug() and the difference is that debug() (defined in "t3lib/config_default.php") will only output information if your IP addresse is within a certain range typical for internal networks.