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Amazon Simple Storage Service
Developer Guide (API Version 2006-03-01)

Publishing Content Using Amazon S3 and BitTorrent

Every anonymously readable object stored in Amazon S3 is automatically available for download using BitTorrent. The process for changing the ACL on an object to allow anonymous READ operations is described in Managing Access Permissions to Your Amazon S3 Resources.

You can direct your clients to your BitTorrent accessible objects by giving them the .torrent file directly or by publishing a link to the ?torrent URL of your object. One important thing to note is that the .torrent file describing an Amazon S3 object is generated on-demand, the first time it is requested (via the REST ?torrent resource). Generating the .torrent for an object takes time proportional to the size of that object. For large objects, this time can be significant. Therefore, before publishing a ?torrent link, we suggest making the first request for it yourself. Amazon S3 might take several minutes to respond to this first request, as it generates the .torrent file. Unless you update the object in question, subsequent requests for the .torrent will be fast. Following this procedure before distributing a ?torrent link will ensure a smooth BitTorrent downloading experience for your customers.

To stop distributing a file using BitTorrent, simply remove anonymous access to it. This can be accomplished by either deleting the file from Amazon S3, or modifying your access control policy to prohibit anonymous reads. After doing so, Amazon S3 will no longer act as a "seeder" in the BitTorrent network for your file, and will no longer serve the .torrent file via the ?torrent REST API. However, after a .torrent for your file is published, this action might not stop public downloads of your object that happen exclusively using the BitTorrent peer to peer network.