A validator to check whether a resource’s name is unique:

<input type="text" id="name" name="name" value="" />
{% validate id="name" type={name_unique} %}

Optionally, pass an id parameter to exclude that particular id when testing for uniqueness. This is useful when you want to exclude the name of the resource currently being edited:

<input type="text" id="name" name="name" value="" />
{% validate id="name" type={name_unique id=id} %}

You can also pass a failure_message:

<input type="text" id="name" name="name" value="" />
{% validate id="name" type={name_unique id=id failure_message=_"Eek! Already used!"} %}

See also

Forms and validation, validator-username_unique