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As an example, if a developer wants to add the capability of showing the version of a datafile that his 3rd party component is working from, there is only one class the developer would need to implement. Assuming the component is called My_Component, he would create a class named My_Component_HelloProvider in a file named HelloProvider.html somewhere on the include_path. This class would implement Zend_Tool_Framework_Provider_Interface, and the body of this file would only have to look like the following:

class My_Component_HelloProvider
    implements Zend_Tool_Framework_Provider_Interface
{
    public function say()
    {
        echo 'Hello from my provider!';
    }
}

Given that code above, and assuming the developer wishes to access this functionality through the console client, the call would look like this:

% zf say hello
Hello from my provider!

The above "Hello World" example is great for simple commands, but what about something more advanced? As your scripting and tooling needs grow, you might find that you need the ability to accept variables. Much like function signatures have parameters, your tooling requests can also accept parameters.

Just as each tooling request can be isolated to a method within a class, the parameters of a tooling request can also be isolated in a very well known place. Parameters of the action methods of a provider can include the same parameters you want your client to utilize when calling that provider and action combination. For example, if you wanted to accept a name in the above example, you would probably do this in OO code:

class My_Component_HelloProvider
    implements Zend_Tool_Framework_Provider_Interface
{
    public function say($name = 'Ralph')
    {
        echo 'Hello' . $name . ', from my provider!';
    }
}

The above example can then be called via the command line zf say hello Joe. "Joe" will be supplied to the provider as a parameter of the method call. Also note, as you see that the parameter is optional, that means it is also optional on the command line, so that zf say hello will still work, and default to the name "Ralph".

Another interesting feature you might wish to implement is pretendability. Pretendabilty is the ability for your provider to "pretend" as if it is doing the requested action and provider combination and give the user as much information about what it would do without actually doing it. This might be an important notion when doing heavy database or filesystem modifications that the user might not otherwise want to do.

Pretendability is easy to implement. There are two parts to this feature: 1) marking the provider as having the ability to "pretend", and 2) checking the request to ensure the current request was indeed asked to be "pretended". This feature is demonstrated in the code sample below.

class My_Component_HelloProvider
    extends    Zend_Tool_Framework_Provider_Abstract
    implements Zend_Tool_Framework_Provider_Pretendable
{
    public function say($name = 'Ralph')
    {
        if ($this->_registry->getRequest()->isPretend()) {
            echo 'I would say hello to ' . $name . '.';
        } else {
            echo 'Hello' . $name . ', from my provider!';
        }
    }
}