function getFeedLink(Craur $value)
{
if ($value->get('@rel', '') === 'feed') {
return $value->get('@href');
}
throw new Exception('This is no feed link!');
}
/**
* Only write the direct descendants into a new row.
*
* @example
* $craur = new Craur(
* array(
* 'name' => 'My Book',
* 'year' => '2012',
* 'categories' => array( // Will be ignored
* 'comedy',
* 'fantasy'
* ),
* 'authors' => array( // Will be ignored
* array('name' => 'Paul'),
* array('name' => 'Erwin')
* ),
* 'pages' => '212'
* )
* );
*
* $expected_data = array(
* 0 => 'My Book',
* 1 => '2012',
* 4 => '212'
* );
*
* $result_data = CraurCsvWriter::extractDirectDescendants($craur, array(
* 'name',
* 'year',
* 'categories[]',
* 'authors[].name',
* 'pages',
* ),'');
*
* assert(json_encode($expected_data) == json_encode($result_data));
* @return array
*/
static function extractDirectDescendants(Craur $craur, $field_mappings, $prefix = '')
{
$row = array();
foreach ($field_mappings as $pos => $field_mapping_with_prefix) {
if (substr($field_mapping_with_prefix, 0, strlen($prefix)) == $prefix) {
/*
* Get rid of the prefix
*/
$field_mapping = substr($field_mapping_with_prefix, strlen($prefix));
if (strpos($field_mapping, '.') === false) {
/*
* Something like: name, age or categories
*
* So the $field_mappings[$pos] is something like: book[].name, book[].author[].age or book[].categories[]
* which indicates, if we want one or multiple values
*/
if (substr($field_mapping, -2, 2) !== '[]') {
/*
* We want one value!
*/
$row[$pos] = $craur->get($field_mapping, '');
}
}
}
}
return $row;
}
function youngerThenThreeYears(Craur $value)
{
if ($value->get('@age') < 3) {
return $value;
}
throw new Exception('Is not younger then three years!');
}
function isACheapBook(Craur $value)
{
if ($value->get('price') > 20) {
throw new Exception('Is no cheap book!');
}
return $value;
}
