MongoDB\ChangeStream::current()

定义

MongoDB\ChangeStream::current()

返回变更流中的当前事件。

function current(): array|object|null

每个事件文档的结构将根据操作类型而有所不同。有关更多信息，请参阅MongoDB手册中的变更事件。

Return Values

变更流中当前事件的大量或对象，如果没有当前事件null即 MongoDB\ChangeStream::valid()返回false ）。返回类型将取决于 MongoDB\Collection::watch() 的typeMap选项

示例

此示例在迭代change stream时报告事件。

<?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;    }}

假设在上述脚本迭代change stream时插入、更新和删除了文档，则输出将类似于以下内容：

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"}

另请参阅