Koine Delayed Cache

Delayed Cache is a wrapper for Zend Cache. Sometimes you have parallel requests want a cached result that was already started, but is still under construction. Delayed cache will wait until it is ready and then it will return the result for you.

Code information:

Package information:

Installing

Installing via Composer

Append the lib to your requirements key in your composer.json.

{
    // composer.json
    // [..]
    require: {
        // append this line to your requirements
        "koine/delayed-cache": "dev-master"
    }
}

Alternative install

• Learn composer. You should not be looking for an alternative install. It is worth the time. Trust me ;-)
• Follow this set of instructions

Usage

$zendCache = $cache  = \Zend\Cache\StorageFactory::adapterFactory(
    'apc',
    array('ttl' => 3600)
);

$delayedCache = new \Koine\DelayedCache\DelayedCache($zendCache);

// index.php, second 10:00:00 am

$cacheKey = 'veryExpansiveCalculation';

$veryExpansiveCalculation = function () {
    sleep(60);

    return '42';
};

// hasItem returns true in the false time
if (!$delayedCache->hasItem($cacheKey)) {
    $delayedCache->setItem($cacheKey, $veryExpansiveCalculation);
}

$answer = $delayedCache->getItem($cacheKey);
echo 'answer is: ' . $answer;

// index.php, 10:00:10 am

$cacheKey = 'veryExpansiveCalculation';

$veryExpansiveCalculation = function () {
    sleep(60);

    return '42';
};

// although the result is not ready yet, hasItem will return true
if (!$delayedCache->hasItem($cacheKey)) {
    $delayedCache->setItem($cacheKey, $veryExpansiveCalculation);
}

// Waits 50 seconds until the building of the cache is done and then returns
// The $veryExpansiveCalculation callback will not be executed twice, unless the
// cache is cleared
$answer = $delayedCache->getItem($cacheKey);
echo 'answer is: ' . $answer;

Alternatively you can use the short method:

$cacheKey = 'veryExpansiveCalculation';

$veryExpansiveCalculation = function () {
    sleep(60);

    return '42';
};

// if cache is not set, it will set and then return the cached value
$answer = $delayedCache->getCachedItem($cacheKey, $veryExpansiveCalculation);
echo 'answer is: ' . $answer;

Issues/Features proposals

Here is the issue tracker.

Contributing

Only TDD code will be accepted. Please follow the PSR-2 code standard.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

How to run the tests:

phpunit

To check the code standard run:

# Fixes code
./bin/php-cs-fix.sh

# outputs error
./bin/php-cs-fix.sh src true
./bin/php-cs-fix.sh test true

Lincense

MIT

Authors

• Marcelo Jacobus