File API
You can create an instance of the DriveFile class using the disk.file method. A File acts as a pointer and can perform read-only operations on a given key.
In the following example, we create an instance of the DriveFile class and then use the file.get method to read its contents.
const disk = new Disk(driver)
const key = 'users/1/avatar.png'
/**
* Create an instance of the file. Creating an
* instance does not load the file contents
*/
const userAvatar = disk.file(key)
/**
* Explicitly read file contents
*/
const contents = await userAvatar.get()
All the read-only methods from the Disk class are also available in the DriveFile class.
const file = disk.file(key)
/**
* Get file contents as a string
*/
await file.get()
/**
* Get file contents as a Readable stream
*/
await file.getStream()
/**
* Get file contents as a Uint8Array
*/
await file.getBytes()
/**
* Get file metadata
*/
await file.getMetaData()
/**
* Check if the file exists within the storage
* layer
*/
await file.exists()
Working with the file snapshot
You can create a snapshot of a file using the file.toSnapshot method and persist it inside the database. The snapshot includes the file key and its metadata. Snapshots can be a great way to list files in a UI without retrieving their metadata from the cloud provider.
const file = disk.file(key)
const snapshot = await file.toSnapshot()
console.log(snapshot)
/**
{
key: 'users/1/avatar.png',
contentType: 'image/png',
contentLength: 31400,
etag: 'W/"b-18f0eb15abf"',
lastModified: '2024-04-24T06:01:09.065Z'
}
*/
Later, you can create an instance of the file from the snapshot using the disk.fromSnapshot method.
The file instance created using the fromSnapshot method caches the file metadata. However, to re-fetch fresh metadata, you must create the file instance using the disk.file method.
const file = disk.fromSnapshot(snapshot)
const metaData = await file.getMetaData()
const file = disk.file(snapshot.key)
const metaData = await file.getMetaData()