Documentation

  require_once('api/class.api.php');
  $api = new civicrm_api3();

or from any code on the same server as civicrm

  require_once('/your/civi/folder/api/class.api.php');
  // the path to civicrm.settings.php
  $api = new civicrm_api3 (['conf_path'=> '/your/path/to/your/civicrm/or/joomla/site']);

or to query a remote server via the rest api

  $api = new civicrm_api3 (['server' => 'http://example.org',
                            'api_key'=>'theusersecretkey',
                            'key'=>'thesitesecretkey']);

No matter how initialised and if civicrm is local or remote, you use the class the same way.

  $api->{entity}->{action}($params);

So, to get the individual contacts:

  if ($api->Contact->Get(['contact_type'=>'Individual','return'=>'sort_name,current_employer']) {
    // each key of the result array is an attribute of the api
    echo "\n contacts found " . $api->count;
    foreach ($api->values as $c) {
      echo "\n".$c->sort_name. " working for ". $c->current_employer;
    }
    // in theory, doesn't append
  } else {
    echo $api->errorMsg();
  }

Or, to create an event:

  if ($api->Event->Create(['title'=>'Test','event_type_id' => 1,'is_public' => 1,'start_date' => 19430429])) {
    echo "created event id:". $api->id;
  } else {
    echo $api->errorMsg();
  }

To make it easier, the Actions can either take for input an associative array $params, or simply an id. The following two lines are equivalent.

  $api->Activity->Get (42);
  $api->Activity->Get (['id'=>42]);

You can also get the result like civicrm_api does, but as an object instead of an array (eg $entity->attribute instead of $entity['attribute']).

  $result = $api->result;
  // is the json encoded result
  echo $api;

For remote calls, you may need to set the UserAgent and Referer strings for some environments (eg WordFence) Add 'referer' and 'useragent' to the initialisation config:

  $api = new civicrm_api3 (['server' => 'http://example.org',
                            'api_key'=>'theusersecretkey',
                            'key'=>'thesitesecretkey',
                            'referer'=>'https://my_site',
                            'useragent'=>'curl']);