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<?php
 /*
 * This file is part of the Predis package.
 *
 * (c) Daniele Alessandri <[email protected]>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
 
 require __DIR__.'/shared.php';
 
 use Predis\Collection\Iterator;
 
 // Starting from Redis 2.8, clients can iterate incrementally over collections
 // without blocking the server like it happens when a command such as KEYS is
 // executed on a Redis instance storing millions of keys. These commands are:
 //
 //   - SCAN (iterates over the keyspace)
 //   - SSCAN (iterates over members of a set)
 //   - ZSCAN (iterates over members and ranks of a sorted set)
 //   - HSCAN (iterates over fields and values of an hash).
 
 // Predis provides a specialized abstraction for each command based on standard
 // SPL iterators making it possible to easily consume SCAN-based iterations in
 // your PHP code.
 //
 // See http://redis.io/commands/scan for more details.
 //
 
 // Create a client using `2.8` as a server profile (needs Redis 2.8!)
 $client = new Predis\Client($single_server, array('profile' => '2.8'));
 
 // Prepare some keys for our example
 $client->del('predis:set', 'predis:zset', 'predis:hash');
 for ($i = 0; $i < 5; ++$i) {
 $client->sadd('predis:set', "member:$i");
 $client->zadd('predis:zset', -$i, "member:$i");
 $client->hset('predis:hash', "field:$i", "value:$i");
 }
 
 // === Keyspace iterator based on SCAN ===
 echo 'Scan the keyspace matching only our prefixed keys:', PHP_EOL;
 foreach (new Iterator\Keyspace($client, 'predis:*') as $key) {
 echo " - $key", PHP_EOL;
 }
 
 /* OUTPUT
 Scan the keyspace matching only our prefixed keys:
 - predis:zset
 - predis:set
 - predis:hash
 */
 
 // === Set iterator based on SSCAN ===
 echo 'Scan members of `predis:set`:', PHP_EOL;
 foreach (new Iterator\SetKey($client, 'predis:set') as $member) {
 echo " - $member", PHP_EOL;
 }
 
 /* OUTPUT
 Scan members of `predis:set`:
 - member:1
 - member:4
 - member:0
 - member:3
 - member:2
 */
 
 // === Sorted set iterator based on ZSCAN ===
 echo 'Scan members and ranks of `predis:zset`:', PHP_EOL;
 foreach (new Iterator\SortedSetKey($client, 'predis:zset') as $member => $rank) {
 echo " - $member [rank: $rank]", PHP_EOL;
 }
 
 /* OUTPUT
 Scan members and ranks of `predis:zset`:
 - member:4 [rank: -4]
 - member:3 [rank: -3]
 - member:2 [rank: -2]
 - member:1 [rank: -1]
 - member:0 [rank: 0]
 */
 
 // === Hash iterator based on HSCAN ===
 echo 'Scan fields and values of `predis:hash`:', PHP_EOL;
 foreach (new Iterator\HashKey($client, 'predis:hash') as $field => $value) {
 echo " - $field => $value", PHP_EOL;
 }
 
 /* OUTPUT
 Scan fields and values of `predis:hash`:
 - field:0 => value:0
 - field:1 => value:1
 - field:2 => value:2
 - field:3 => value:3
 - field:4 => value:4
 */
 
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