Panels 2: Creating contexts and relationships that are node type aware

Contexts

When creating a new pane for panels 2, you might add a content type like:

  $types['foo'] = array(
    'title' => t('Foo'),
    'icon' => 'icon_node.png',
    'path' => panels_get_path('content_types/node'),
    'category' => array(t('FooP'), -9),
    'required context' => new panels_required_context(t('Node'), 'node'),
  );

This new pane will only be available if a node context exists. What if you only want it to be available to specify node types, because you require specific CCK fields? You can actually require a context of a specific node type.

  $types['foo'] = array(
    'title' => t('Foo'),
    'icon' => 'icon_node.png',
    'path' => panels_get_path('content_types/node'),
    'category' => array(t('FooP'), -9),
    'required context' => new panels_required_context(t('Node'), 'node-page'),
  );

Now the pane will only be available when a context to a 'page' node exists.

Relationships

When creating a relationship between argument contexts and other contexts, it's also possible to specify node types. You may normally write a relationship like:

function my_module_panels_relationships() {
  $args['foo_from_node'] = array(
    'title' => t("Foo from Node"),
    'keyword' => 'foo',
    'description' => t('Adds a Foo from a Node context.'),
    'required context' => new panels_required_context(t('Node'), 'node'),
    'context' => 'my_module_foo_from_node_context',
  );
  return $args;
}

function my_module_foo_from_node_context($context = NULL, $conf) {
  // If unset it wants a generic, unfilled context, which is just NULL
  if (empty($context->data)) {
    return panels_context_create_empty('node', NULL);
  }

  if ($node = get_some_other_node($context->data)) {
    return panels_context_create('node', $node);
  }
}

This relationship will require a node context before adding a 'foo' context. However, it's simple to add a node type specific requirement:

function my_module_panels_relationships() {
  $args['foo_from_page'] = array(
    'title' => t("Foo from Page"),
    'keyword' => 'foo',
    'description' => t('Adds a Foo from a Page context.'),
    'required context' => new panels_required_context(t('Page'), 'node-page'),
    'context' => 'my_module_foo_from_page_context',
  );
  return $args;
}

function my_module_foo_from_page_context($context = NULL, $conf) {
  // If unset it wants a generic, unfilled context, which is just NULL
  if (empty($context->data)) {
    return panels_context_create_empty('node', array('types' => array('page')));
  }

  if ($node = get_some_other_node($context->data)) {
    return panels_context_create('node', $node);
  }
}

Now the relationship will required a 'page' node context before allowing the 'foo' context to be added.