Introduction

The CollectionFS package makes available two important global variables: FS.File and FS.Collection.

• An FS.File instance wraps a file and its data on the client or server. It is similar to the browser File object (and can be created from one), but it has additional properties and methods. Many of its methods are reactive when the instance is returned by a call to the collection's find or findOne.
• An FS.Collection provides a collection in which information about files can be stored. It is backed by an underlying normal Mongo.Collection instance. Most collection methods, such as find and insert are available on the FS.Collection instance. If you need to call other collection methods such as _ensureIndex, you can call them directly on the underlying Mongo.Collection instance available through myFSCollection.files.

A document from an FS.Collection is transformed into an FS.File.

CollectionFS also provides an HTTP upload package that has the necessary mechanisms to upload files, track upload progress reactively, and pause and resume uploads. This can be swapped for a DDP upload package, but we do not currently recommend using DDP for uploads due to known issues with the current DDP spec and large files.