The context module provides great flexibility in terms of the available ways to set a context, but it's also remarkably straightforward to define custom conditions.
In order to set arbitrary contexts, hook_context_conditions() is implemented to define values and such. This example will use the value of a CCK field, called field_foo:
/** * Implementation of hook_context_conditions(). */ function mymodule_context_conditions() { $items = array(); // The key used here will be used below when setting the context. $items['mymodule_foo'] = array( '#title' => t('Field Foo Value'), '#description' => t('Set this when field_foo has a certain value.'), '#options' => array( // Note, these are hardcoded here for simplicity, but could // easily use something like CCK's content_allowed_values() api // function for more dynamic population. 'value1' => t('Label 1'), 'value2' => t('Label 2'), ), '#type' => 'checkboxes', ); return $items; }
The only other step is to actually fire the code that sets the context somewhere. In the example of setting a context based on the value of a CCK field, this can be done in hook_nodeapi(). But something like hook_init() can also be used.
function mymodule_nodeapi(&$node, $op, $teaser, $page) { if (isset($node->field_foo[0]['value']) && $op == 'view' && $page && menu_get_object() === $node) { // Use the same key here as used to define the context condition // above. Note, this logic would need some re-working if // field_foo allowed multiple values. context_set_by_condition('mymodule_foo', check_plain($node->field_foo[0]['value'])); } }
That's it. Contexts can now be added through the UI or through code that react to the value of field_foo.
