Status response objects are needed mostly to make it possible from the
client perspective to differentiate a status response with the payload
"OK" from a normale bulk reply containing "OK".
The biggest change is for commands returning +OK responses: these were
previously translated to TRUE (bool value), but they are now returned
as instances of Predis\Response\Status. Just to illustrate an example
of the possibilities with this change we will use SET since it is the
most widely used command returning +OK:
$response = $client->set('foo', 'bar');
echo $response; // 'OK'
$response == 'OK'; // TRUE
isset($response->ok); // TRUE
$response == true; // TRUE
$response === true; // FALSE
$response instanceof Predis\Response\ObjectInterface; // TRUE
$response instanceof Predis\Response\Status; // TRUE
For those checking responses returned by commands such as SET or PONG,
the breaking change basically lies in the usage of strict comparison:
doing $response === true will now evaluate to FALSE instead of TRUE.
By default Predis caches common status responses such as OK or QUEUED
to lower the memory usage when using pipelines or transactions.
Supporting this feature has been problematic and leaded to some ugly
code to make abstractions such as pipelines and transactions aware of
these kind of response objects. Furthermore, it was not possible to
add them to all the connection classes due to implementation limits.
For such reasons Predis do not support them globally anymore, but the
actual classes are still shipped within the library so that they can
be used to build custom stuff at a level lower than client (that is,
unless we decide to remove them for good before going stable).
This class works just like Predis\Connection\PhpiredisConnection but
it does not require the socket extensions since it relies on PHP's
native streams thus allowing the use of persistent connections.
Daniele Alessandri