MongoDB\ChangeStream::current()

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定义

返回值
示例
另请参阅

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。请参阅变更事件中的MongoDB手册以获取更多信息。

返回值

一个数组或对象，表示变更流中的当前事件，如果没有当前事件（即MongoDB\ChangeStream::valid()返回false），则返回null。返回类型将取决于MongoDB\Collection::watch()的typeMap选项。MongoDB\ChangeStream::valid()

示例

此示例在遍历变更流时报告事件。

<?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;
    }
}

假设在上述脚本遍历变更流时，已插入、更新和删除了文档，则输出将类似于

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

ChangeStream 类

getCursorId()