What can I use for quick temporary storage in PHP

Question

I am creating a small plugin that process some images. Now to report the progress back to the user I have a small ajax script that will long poll the results back.

Now intern I need an object that keeps track of what is processed. Now the options I am aware of are the following.

Using the PHP session object. I cannot use this in this specific case, because the initial process is also done by ajax. So the main process is a ajax call, and the long poll ajax is another ajax call. They have 2 different session id's, so they do not communicate well.

Second option is to use the database as the storage. I do not know if this is so good because there will be around 40 read / writes on an average job. I know that this is no problem, but it seems a little much for something so simple.

What I actual look for is a sort of memory object if that is possible. Create a small object in the memory that is rapidly updated with the progress and deleted when we are done.

I do not know if that is possible, exists such a thing in PHP, and can I make use of this. Note that this will be a public plugin, so I need to work with methods that are available on all kind of systems, nothing special.

Answer 1

I think database is not the worse solution. If you think write in disk, maybe can be worse.

Memcache is good, but you need a "external plugins free" small plugin who runs easily on win, linux, mac, and so on... is not a good option.

If you use Mysql, you can use Memory engine tables, witch is fast, and truncate it or clean it periodically, with a simple garbage collector algoritm. And if memory table is not a option, innodb is good enough.

Answer 2

You can use memcache for this. http://php.net/manual/en/book.memcache.php As key you can use a md5 hash of the image file plus the users ip.