================================
MongoDB\\ChangeStream::current()
================================
.. default-domain:: mongodb
.. contents:: On this page
:local:
:backlinks: none
:depth: 1
:class: singlecol
Definition
----------
.. phpmethod:: MongoDB\\ChangeStream::current()
Returns the current event in the change stream.
.. code-block:: php
function current(): array|object|null
The structure of each event document will vary based on the operation type.
See :manual:`Change Events </reference/change-events/>` in the MongoDB manual
for more information.
Return Values
-------------
An array or object for the current event in the change stream, or ``null`` if
there is no current event (i.e. :phpmethod:`MongoDB\\ChangeStream::valid()`
returns ``false``). The return type will depend on the ``typeMap`` option for
:phpmethod:`MongoDB\\Collection::watch()`.
Examples
--------
This example reports events while iterating a change stream.
.. code-block:: php
<?php
$uri = 'mongodb://rs1.example.com,rs2.example.com/?replicaSet=myReplicaSet';
$collection = (new MongoDB\Client($uri))->test->inventory;
$changeStream = $collection->watch();
for ($changeStream->rewind(); true; $changeStream->next()) {
if ( ! $changeStream->valid()) {
continue;
}
$event = $changeStream->current();
$ns = sprintf('%s.%s', $event['ns']['db'], $event['ns']['coll']);
$id = json_encode($event['documentKey']['_id']);
switch ($event['operationType']) {
case 'delete':
printf("Deleted document in %s with _id: %s\n\n", $ns, $id);
break;
case 'insert':
printf("Inserted new document in %s\n", $ns);
echo json_encode($event['fullDocument']), "\n\n";
break;
case 'replace':
printf("Replaced new document in %s with _id: %s\n", $ns, $id);
echo json_encode($event['fullDocument']), "\n\n";
break;
case 'update':
printf("Updated document in %s with _id: %s\n", $ns, $id);
echo json_encode($event['updateDescription']), "\n\n";
break;
}
}
Assuming that a document was inserted, updated, and deleted while the above
script was iterating the change stream, the output would then resemble:
.. code-block:: none
Inserted new document in test.inventory
{"_id":{"$oid":"5a81fc0d6118fd1af1790d32"},"name":"Widget","quantity":5}
Updated document in test.inventory with _id: {"$oid":"5a81fc0d6118fd1af1790d32"}
{"updatedFields":{"quantity":4},"removedFields":[]}
Deleted document in test.inventory with _id: {"$oid":"5a81fc0d6118fd1af1790d32"}
See Also
--------
- :phpmethod:`MongoDB\\Client::watch()`
- :phpmethod:`MongoDB\\Collection::watch()`
- :phpmethod:`MongoDB\\Database::watch()`
- :php:`Iterator::current() <iterator.current>`
- :ref:`Tailable Cursor Iteration <php-tailable-cursor>`
- :manual:`Change Streams </changeStreams>` documentation in the MongoDB manual
- :manual:`Change Events </reference/change-events/>` documentation in the
MongoDB manual
|
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