/**
* Prepend data to an existing item.
*
* This method should throw an error if it is used with compressed data. This is an expected behavior.
* Memcached casts the value to be prepended to the initial value to the type of the initial value. Be
* careful as this leads to unexpected behavior at times. For instance, prepending (float) 45.23 to
* (int) 23 will result in 45, because the value is first combined (45.2323) then cast to "integer"
* (the original value), which will be (int) 45. Due to how memcached treats types, the behavior has been
* mimicked in the internal cache to produce similar results and improve consistency. It is recommend
* that prepends only occur with data of the same type.
*
* @link http://www.php.net/manual/en/memcached.prepend.php
*
* @param string $key The key under which to store the value.
* @param string $value Must be string as prepending mixed values is not well-defined.
* @param string $group The group value prepended to the $key.
* @param string $server_key The key identifying the server to store the value on.
* @param bool $byKey True to store in internal cache by key; false to not store by key
* @return bool Returns TRUE on success or FALSE on failure.
*/
public function prepend($key, $value, $group = 'default', $server_key = '', $byKey = false)
{
if (!is_string($value) && !is_int($value) && !is_float($value)) {
return false;
}
$derived_key = $this->buildKey($key, $group);
// If group is a non-Memcached group, prepend to runtime cache value, not Memcached
if (in_array($group, $this->no_mc_groups)) {
if (!isset($this->cache[$derived_key])) {
return false;
}
$combined = $this->combine_values($this->cache[$derived_key], $value, 'pre');
$this->add_to_internal_cache($derived_key, $combined);
return true;
}
// Append to Memcached value
if (false !== $byKey) {
$result = $this->mc->prependByKey($server_key, $derived_key, $value);
} else {
$result = $this->mc->prepend($derived_key, $value);
}
// Store in runtime cache if add was successful
if (Memcached::RES_SUCCESS === $this->getResultCode()) {
$combined = $this->combine_values($this->cache[$derived_key], $value, 'pre');
$this->add_to_internal_cache($derived_key, $combined);
}
return $result;
}
/**
* Prepends a value to the end of an existing cached value.
*
* If the value doesn't exist, it will be set with the given value
*
* @param String $key The key for the value
* @param mixed $value The value to prepend
* @param Integer $expire The lifespan of this cache value, in seconds
* @return \r8\Cache\Memcached Returns a self reference
*/
public function prepend($key, $value, $expire = 0)
{
if (!$this->memcached->prepend($this->prepareKey($key), (string) $value)) {
$this->set($key, $value, $expire);
}
$this->handleErrors();
return $this;
}
public function testPrependReplaceFailed()
{
$request = new MemcacheGetRequest();
$request->addKey("widgets_float");
$request->setForCas(true);
$response = new MemcacheGetResponse();
$item = $response->addItem();
$item->setKey("widgets_float");
$item->setValue("bar");
$item->setFlags(0);
// string.
$item->setCasId(123456);
$this->apiProxyMock->expectCall('memcache', 'Get', $request, $response);
$request = new MemcacheSetRequest();
$item = $request->addItem();
$item->setKey("widgets_float");
$item->setValue("foobar");
$item->setFlags(0);
// string
$item->setCasId(123456);
$item->setSetPolicy(SetPolicy::CAS);
$item->setExpirationTime(0);
$response = new MemcacheSetResponse();
$response->addSetStatus(SetStatusCode::NOT_STORED);
$this->apiProxyMock->expectCall('memcache', 'Set', $request, $response);
$memcached = new Memcached();
$memcached->setOption(Memcached::OPT_PREFIX_KEY, "widgets_");
$this->assertFalse($memcached->prepend("float", "foo", 30));
$this->assertEquals($memcached->getResultCode(), Memcached::RES_NOTSTORED);
$this->apiProxyMock->verify();
}
<?php
$cache = new Memcached();
$cache->setOption(Memcached::OPT_BINARY_PROTOCOL, true);
$cache->setOption(Memcached::OPT_COMPRESSION, false);
$cache->addServer('localhost', 3434);
$cache->add("add_key", "hello", 500);
$cache->append("append_key", "world");
$cache->prepend("prepend_key", "world");
$cache->increment("incr", 2, 1, 500);
$cache->decrement("decr", 2, 1, 500);
$cache->delete("delete_k");
$cache->flush(1);
var_dump($cache->get('get_this'));
$cache->set('set_key', 'value 1', 100);
$cache->replace('replace_key', 'value 2', 200);
$cache->getStats();
$cache->quit();
sleep(1);
/**
* @inheritdoc
*/
public function prepend($key, $value, $expiration = null)
{
$key = $this->prefix . $key;
return parent::prepend($key, $value, $expiration);
}
