How to use SCAN with the MATCH option in Predis

Question

I have previously used the KEYS command to search for keys matching a certain pattern in my Redis database. Since Redis 2.8, the SCAN command seems to be preferred over KE

Answer 1

I found how to do it in the Predis examples directory.

To use SCAN to search for matching keys in a database, you simply use the Predis\Collection\Iterator\Keyspace class:

use Predis\Collection\Iterator;

$client = ...;
$pattern = 'foo*';

foreach (new Iterator\Keyspace($client, $pattern) as $key) {
    ...
}

Apparently Predis has an iterator class in Predis\Collection\Iterator for each of the commands that return iterators:

• Keyspace for SCAN
• HashKey for HSCAN
• SetKey for SSCAN
• SortedSetKey for ZSCAN
• ListKey for LRANGE - This doesn't really use Redis iterators, but it's a nice interface to LRANGE anyway.

Answer 2

Maybe this is helpful for other Predis beginners and you're coming from a PHP/MySQL background like me you can use this:

foreach (new Iterator\HashKey($client, $pattern) as $index => $value) {
    ...
}

When you previously generated an array dataset with $client->hmset($index, $array).