php-cache/cache

@james_beninger_twitter I don't know about md5 vs sha1, but I've been using a custom method with success. It has the advantage to accept anything as input, including objects:

/**
 * Returns a unique key identifying all arguments in the array, so we can use the result as cache key
 *
 * This only works for in-memory objects. The key returned should *never* be
 * persisted. And it may be expensive in memory because object are forced
 * not to be garbage collected.
 *
 * @param mixed $value
 *
 * @return string
 */
public static function getCacheKey($value): string
{
    static $preventGarbageCollectorFromDestroyingObject = [];

    if (is_object($value)) {
        $preventGarbageCollectorFromDestroyingObject[] = $value;

        return spl_object_hash($value);
    }

    if (is_array($value)) {
        $key = '[ARRAY|';
        foreach ($value as $i => $modelInCollection) {
            $key .= $i . '>' . self::getCacheKey($modelInCollection) . ':';
        }

        return $key . ']';
    }

    if (is_bool($value)) {
        return '[BOOL|' . $value . ']';
    }

    if ($value === null) {
        return '[NULL]';
    }

    return (string) $value;
}

Common usages could be something like:

function doSomethingExpansive($currentUser, $foo)
{
    $key = Cache::getCacheKey(func_get_args());

    $keyWithExtrasStuff = Cache::getCacheKey([
        $currentUser,
        $foo,
        $bar,
    ]);
    // ...
}