Check if a taxonomy term synonym exists

Question

I have a $category variable containing country names separated by comma. So I use the following code to save them as taxonomy terms:

$tids = array(); $ctids = array();
$category = explode(',',$category);
foreach($category as $cat) {
  insert_term_if_not_exists($cat, 'countries');
  $term_country = taxonomy_get_term_by_name($cat);
  $tid_country = key($term_country);
  $lang_country = field_language('node', $node, 'field_country');
  array_push($ctids, $tid_country);
}
foreach ($ctids as $index => $ctid) { 
 $node->field_country[$lang_country][$index]['tid'] = $ctid; 
}

As you see the above code uses the insert_term_if_not_exists() function which works perfectly well to check if a taxonomy term exists and to create it programmatically if it doesn't:

function insert_term_if_not_exists($term_name, $vocabulary_name) {
   $vocabulary = taxonomy_vocabulary_machine_name_load($vocabulary_name);
   $matched_terms = taxonomy_get_term_by_name($term_name, $vocabulary->machine_name);
  if(empty($matched_terms)) {
    $term = new stdClass();
    $term->vid = $vocabulary->vid;
    $term->name = $term_name;
    taxonomy_term_save($term);
  } else {
    $term = array_shift($matched_terms);
  }
return $term;
}

However, I also need to check and avoid creating a new taxonomy term if it is a synonym of already existing another taxonomy term. So I modified the above code in the following way:

function insert_term_if_not_exists($term_name, $vocabulary_name) {
   $vocabulary = taxonomy_vocabulary_machine_name_load($vocabulary_name);
   $matched_terms = taxonomy_get_term_by_name($term_name, $vocabulary->machine_name);

    if(empty($matched_terms)) {
      $matched_synonym = synonyms_get_term_by_synonym($term_name, $vocabulary);
      if (empty($matched_synonym)) {
        $term = new stdClass();
        $term->vid = $vocabulary->vid;
        $term->name = $term_name;
        taxonomy_term_save($term);
      } else {
        /*
        * Here I need to do something, but don't know what exactly. Using
        * $term = taxonomy_term_load($matched_synonym);
        * here doesn't work.
        */
        }
    } else {
        $term = array_shift($matched_terms);
    }
  return $term;
}

Having troubles to make it work properly.

Answer 1

Edited my answer since my original answer referred to dev code.

The following simple module works with Drupal 7.34 and the current stable version of synonyms (7.x-1.2) and successfully matches a synonym to a taxonomy term.

synonyms_test.module:

function synonyms_test_menu() {
  $menu['test-synonyms'] = array(
    'page callback' => 'synonyms_test_page',
    'access callback' => TRUE,
  );

  return $menu;
}

function synonyms_test_page() {
  $vocabulary_name = 'tags';
  $output = '<p>Assuming you have a taxonomy with machine name "tags" and that '
            . 'taxonomy has a term named "first term" and that term has a '
            . 'synonym "syn one", this test will produce these results:</p>';
  $test_terms = array('first term', 'bogus term', 'syn one');
  $vocabulary = taxonomy_vocabulary_machine_name_load($vocabulary_name);
  foreach($test_terms as $test_term) {
    $output .= 'Testing "' . $test_term . '"<br>';
    $matched_terms = taxonomy_get_term_by_name($test_term, $vocabulary->machine_name);
    if(empty($matched_terms)) {
      $output .= 'Not an existing taxonomy term.';
    } else {
      $output .= 'Is an existing taxonomy term.';
    }
    $output .= '<br><br>';
    $matched_synonym = synonyms_get_term_by_synonym($test_term, $vocabulary);
    if(empty($matched_synonym)) {
      $output .= 'Not an existing synonym.';
    }
    else {
      $output .= 'Is an existing synonym, for tid ' . $matched_synonym;
    }
    $output .= '<br>=========<br><br>';
  }
  return $output;
}

* Original answer below *

This is the function you're looking for (from synonyms.module):

/**
 * Returns the term objects that have the given string as a synonym.
 *
 * @param $synonym
 *  A string containing the synonym to search for.
 * @param $vocabulary
 *  (optional) The machine name of the vocabulary in which to search for.

 * @return
 *  An array of term objects containing that synonym.
 */
function synonyms_root_terms_get($synonym, $vocabulary = NULL) {
  $tids = synonyms_root_tids_get($synonym, $vocabulary);

  return taxonomy_term_load_multiple($tids);
}

So if your $matched_terms is empty, try something like:

$matched_synonyms = synonyms_root_terms_get($term_name, $vocabulary->machine_name);
if(empty($matched_synonyms)) {
  // ...now create your new term
}
else {
  $term = array_shift($matched_synonyms);
}