PHP Class Google\Cloud\Datastore\DatastoreSessionHandler
Instead of storing the session data in a local file, it stores the data to
Cloud Datastore. The biggest benefit of doing this is the data can be
shared by multiple instances, so it's suitable for cloud applications.
The downside of using Cloud Datastore is the write operations will cost you
some money, so it is highly recommended to minimize the write operations
with your session data with this handler. In order to do so, keep the data
in the session as limited as possible; for example, it is ok to put only
signed-in state and the user id in the session with this handler. However,
for example, it is definitely not recommended that you store your
application's whole undo history in the session, because every user
operations will cause the Datastore write and then it will cost you lot of
money.
This handler doesn't provide pessimistic lock for session data. Instead, it
uses Datastore Transaction for data consistency. This means that if
multiple requests are modifying the same session data simultaneously, there
will be more probablity that some of the
write operations will fail.
If you are building an ajax application which may issue multiple requests
to the server, please design the session data carefully, in order to avoid
possible data contentions. Also please see the 2nd example below for how to
properly handle errors on
write operations.
It uses the session.save_path as the Datastore namespace for isolating the
session data from your application data, it also uses the session.name as
the Datastore kind, the session id as the Datastore id. By default, it
does nothing on gc for reducing the cost. Pass positive value up to 1000
for $gcLimit parameter to delete entities in gc.
Note: The datastore transaction only lasts 60 seconds. If this handler is
used for long running requests, it will fail on
write.
Example without error handling:
use Google\Cloud\ServiceBuilder;
$cloud = new ServiceBuilder();
$datastore = $cloud->datastore();
or just $datastore = new \Google\Cloud\Datastore\DatastoreClient();
$handler = new DatastoreSessionHandler($datastore);
session_set_save_handler($handler, true);
session_save_path('sessions');
session_start();
Then read and write the $_SESSION array.
The above example automatically writes the session data. It's handy, but
the code doesn't stop even if it fails to write the session data, because
the
write happens when the code exits. If you want to know the session
data is correctly written to the Datastore, you need to call
session_write_close() explicitly and then handle
E_USER_WARNING
properly like the following example.
Example with error handling:
use Google\Cloud\ServiceBuilder;
$cloud = new ServiceBuilder();
$datastore = $cloud->datastore();
or just $datastore = new \Google\Cloud\Datastore\DatastoreClient();
$handler = new DatastoreSessionHandler($datastore);
session_set_save_handler($handler, true);
session_save_path('sessions');
session_start();
Then read and write the $_SESSION array.
function handle_session_error($errNo, $errStr, $errFile, $errLine) {
# We throw an exception here, but you can do whatever you need.
throw new Exception("$errStr in $errFile on line $errLine", $errNo);
}
set_error_handler('handle_session_error', E_USER_WARNING);
If write
fails for any reason, an exception will be thrown.
session_write_close();
restore_error_handler();
You can still read the $_SESSION array after closing the session.
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Open project: GoogleCloudPlatform/gcloud-php
Class Usage Examples
Méthodes publiques
Méthode |
Description |
|
__construct ( DatastoreClient $datastore, integer $gcLimit = self::DEFAULT_GC_LIMIT ) |
Create a custom session handler backed by Cloud Datastore. |
|
close ( ) |
Just return true for this implementation. |
|
destroy ( $id ) |
Delete the session data from Cloud Datastore. |
|
gc ( $maxlifetime ) |
Delete the old session data from Cloud Datastore. |
|
open ( string $savePath, string $sessionName ) : boolean |
Start a session, by creating a transaction for the later write. |
|
read ( $id ) |
Read the session data from Cloud Datastore. |
|
write ( $id, $data ) |
Write the session data to Cloud Datastore. |
|
Method Details
__construct()
public méthode
Create a custom session handler backed by Cloud Datastore.
public __construct ( DatastoreClient $datastore, integer $gcLimit = self::DEFAULT_GC_LIMIT ) |
$datastore |
DatastoreClient |
Datastore client. |
$gcLimit |
integer |
[optional] A number of entities to delete in the
garbage collection. Defaults to 0 which means it does nothing.
The value larger than 1000 will be cut down to 1000. |
Just return true for this implementation.
Delete the session data from Cloud Datastore.
Delete the old session data from Cloud Datastore.
public gc ( $maxlifetime ) |
Start a session, by creating a transaction for the later write.
public open ( string $savePath, string $sessionName ) : boolean |
$savePath |
string |
The value of `session.save_path` setting will be
used here. It will use this value as the Datastore namespaceId. |
$sessionName |
string |
The value of `session.name` setting will be
used here. It will use this value as the Datastore kind. |
Résultat |
boolean |
|
Read the session data from Cloud Datastore.
Write the session data to Cloud Datastore.
public write ( $id, $data ) |