Resource sharing plugin for nestor

This plugin enables other plugins to share resources, ie make them available for download to users without authorized access to nestor, with a random and short URL. Shares can be manually revoked or suspended at any time.

Shared resources can also have limits, for example:

• A maximum number of downloads
• An expiration date
• A list of allowed client IP addresses

Sharing resources

To share a resource, a plugin must :

• define a share provider function with the share:provider intent
• add a document to the Share model collection, with the provider name and a resource ID

It's then up to the share provider to resolve the resource ID to what is actually intended to be shared, and build the actual download file. The Share model does not allow storing the actual contents of the download, instead it must be determined dynamically by the share provider function.

Internals

Models

Share: a model to store shared resources, along with their limits. Each share has a provider name and a provider-specific resource ID.

REST resources

/shares/:id: access to shared resource definitions.

HTTP resources

/downloads/:id: download shared resource

Intents

share:provider: used by plugins to declare a "share provider", that is, a handler that is able, given a resource ID, build a downloadable file. This intent must be dispatched with the following arguments:

• the provider name
• the share provider function

The provider function is called when a shared resource is requested by a client, and receives the resource ID, a DownloadStreamBuilder object and a callback as arguments. It should build the download using the DownloadStreamBuilder, and then call the callback (with an optional error argument).

DownloadStreamBuilder usage

A DownloadStreamBuilder provides methods to add contents to a download. If multiple files have been added to the builder, a ZIP archive will be sent to the client.

• DownloadStreamBuilder#addContent(name, content) creates a new file named name with content content. When building downloads with multiple files, name can be a relative path in the archive; parent directories are created automatically.
• DownloadStreamBuilder#addFile(name, path) adds an existing file path with name name. When building downloads with multiple files, name can be a relative path in the archive; parent directories are created automatically.
• DownloadStreamBuilder#addDirectory(name, path) adds an existing directory path, including its contents, under relative path name in the archive.
• DownloadStreamBuilder#setDownloadFilename(name) sets the name of the file to be sent to the client.

The name of the file sent to the client is determined as follows:

• if setDownloadFilename has been called, the name it received
• otherwise, if the download contains a single file, the basename of this file
• otherwise, if the download contains a single directory, the basename of this directory with a ".zip" extension
• otherwise, "download.zip"