# MongoGridFSCursor::key

(PECL mongo >=0.9.0)

MongoGridFSCursor::key — Returns the current result's filename

### Description

public MongoGridFSCursor::key ( ) : string

### Parameters

This function has no parameters.

### Return Values

The current result's _id as a string.

### Changelog

Version | Description
--- | ---
PECL mongo 1.3.0 | The document's `_id` is returned as a string value, since the key should be unique. Pre-1.3.0, `filename` was returned.