Each webbox is composed of several files and is stored in a single directory with an index.php3 file. To call a boxaction, the desired webbox's index.php3 URL is called and also passed the name of the boxaction to call along with any arguments to it. A typical URL style call would look like:

A typical form-based call to the same boxaction can be written:

A given webbox's boxactions are implemented in a single class called a "gateway". The index.php3 script instantiates the "gateway" class for its box. A long switch statement on the $boxaction parameter chooses the boxaction to call. Continuing our "add a customer" example, the relevant snippet of code from the index.php3 file might look like this:

As is clear from this example, the gateway class is stored in a file named gateway.php3, and the class is named "Gateway_<name>", where <name> is the "name" you've given to the box (in our example the name is "People"). The gateway class is stored in a .php3 file to avoid exposing secrets like passwords or other sensitive information you don't want the public to see. It should only contain the class definition, no active script or HTML. Having the gateway class is necessary for calls to a webbox from script outside its directory [For you fusebox aficionados out there, the gateway is necessary because there is no <CFMODULE> tag in PHP which allows you to pass arbitrary arguments.]