What's the best way to degrade gracefully when using a Plugin Variable?

Question

When providing plugin users with variable containing arguments like {{ craft.pluginname.variable(arg1, arg2) }} what's the best practice for returning something that doesn't throw an Internal Server Error exception for Missing argument 1 or argument 2?

Should this be done as part of the /services/PluginService.php or somewhere else? Is it better to return a nicer Javascript console error (or Craft error log) vs. crashing the page?

Answer 1

I think the best way to do this would be in your PluginHandleVariable file's method, just have it accept one, optional parameter and expect it to be an array.

public function variableMethod($options = null)
{
    if (!$options || !is_array($options))
    {
        return "No options set";
    }

    // Now you can check for individual options on the array
    if (isset($options['option1'])
    {
        ....
    }

}

Then both of these would work:

if craft.pluginname.variable()
if craft.pluginname.variable(options)

Answer 2

You can use the is defined twig expression to determine if a variable is defined or not. Something like this:

{% if craft.pluginname.variable(arg1, arg2) is defined %}
    {{ craft.pluginname.variable(arg1, arg2) }}
{% elseif %}
    <p class="notice">Display notice.</p>.
{% endif %}