/**
* Generate OKAPI changelog entries. This method will call $feeder_method OKAPI
* service with the following parameters: array($feeder_keys_param => implode('|', $key_values),
* 'fields' => $fields). Then it will generate the changelog, based on the result.
* This looks pretty much the same for various object types, that's why it's here.
*
* If $use_cache is true, then all the dictionaries from $feeder_method will be also
* kept in OKAPI cache, for future comparison.
*
* In normal mode, update the changelog and don't return anything.
* In fulldump mode, return the generated changelog entries *instead* of
* updating it.
*/
private static function generate_changelog_entries($feeder_method, $object_type, $feeder_keys_param, $key_name, $key_values, $fields, $fulldump_mode, $use_cache, $cache_timeout = 86400)
{
# Retrieve the previous versions of all objects from OKAPI cache.
if ($use_cache) {
$cache_keys1 = array();
$cache_keys2 = array();
foreach ($key_values as $key) {
$cache_keys1[] = 'clog#' . $object_type . '#' . $key;
}
foreach ($key_values as $key) {
$cache_keys2[] = 'clogmd5#' . $object_type . '#' . $key;
}
$cached_values1 = Cache::get_many($cache_keys1);
$cached_values2 = Cache::get_many($cache_keys2);
if (!$fulldump_mode) {
Cache::delete_many($cache_keys1);
Cache::delete_many($cache_keys2);
}
unset($cache_keys1);
unset($cache_keys2);
}
# Get the current values for objects. Compare them with their previous versions
# and generate changelog entries.
require_once $GLOBALS['rootpath'] . 'okapi/service_runner.php';
$current_values = OkapiServiceRunner::call($feeder_method, new OkapiInternalRequest(new OkapiInternalConsumer(), null, array($feeder_keys_param => implode("|", $key_values), 'fields' => $fields, 'attribution_append' => 'static')));
$entries = array();
foreach ($current_values as $key => $object) {
if ($object !== null) {
# Currently, the object exists.
if ($use_cache) {
# First, compare the cached hash. The hash has much longer lifetime
# than the actual cached object.
$cached_md5 = $cached_values2['clogmd5#' . $object_type . '#' . $key];
$current_md5 = md5(serialize($object));
if ($cached_md5 == $current_md5) {
# The object was not changed since it was last replaced.
continue;
}
$diff = self::get_diff($cached_values1['clog#' . $object_type . '#' . $key], $object);
if (count($diff) == 0) {
# Md5 differs, but diff does not. Weird, but it can happen
# (e.g. just after the md5 extension was introduced, or if
# md5 somehow expired before the actual object did).
continue;
}
}
$entries[] = array('object_type' => $object_type, 'object_key' => array($key_name => $key), 'change_type' => 'replace', 'data' => $use_cache ? $diff : $object);
if ($use_cache) {
# Save the last-published state of the object, for future comparison.
$cached_values2['clogmd5#' . $object_type . '#' . $key] = $current_md5;
$cached_values1['clog#' . $object_type . '#' . $key] = $object;
}
} else {
# Currently, the object does not exist.
if ($use_cache && $cached_values1['clog#' . $object_type . '#' . $key] === false) {
# No need to delete, we have already published its deletion.
continue;
}
$entries[] = array('object_type' => $object_type, 'object_key' => array($key_name => $key), 'change_type' => 'delete');
if ($use_cache) {
# Cache the fact, that the object was deleted.
$cached_values2['clogmd5#' . $object_type . '#' . $key] = false;
$cached_values1['clog#' . $object_type . '#' . $key] = false;
}
}
}
if ($fulldump_mode) {
return $entries;
} else {
# Save the entries to the clog table.
if (count($entries) > 0) {
$data_values = array();
foreach ($entries as $entry) {
$data_values[] = gzdeflate(serialize($entry));
}
Db::execute("\n insert into okapi_clog (data)\n values ('" . implode("'),('", array_map('mysql_real_escape_string', $data_values)) . "');\n ");
}
# Update the values kept in OKAPI cache.
if ($use_cache) {
Cache::set_many($cached_values1, $cache_timeout);
Cache::set_many($cached_values2, null);
# make it persistent
}
}
}
/** Same as `cache_get`, but it works on multiple keys at once. */
public static function get_many($keys)
{
$prefixed_keys = array();
foreach ($keys as $key) {
$prefixed_keys[] = "facade#" . $key;
}
$prefixed_result = Cache::get_many($prefixed_keys);
$result = array();
foreach ($prefixed_result as $prefixed_key => &$value_ref) {
$result[substr($prefixed_key, 7)] =& $value_ref;
}
return $result;
}
