Support path-style endpoints

Problem/Motivation

According to the Amazon S3 documentation:

Amazon S3 supports both virtual-hosted–style and path-style URLs to access a bucket.

• In a virtual-hosted–style URL, the bucket name is part of the domain name in the URL. For example:

  • http://bucket.s3.amazonaws.com

  • http://bucket.s3-aws-region.amazonaws.com.

  In a virtual-hosted–style URL, you can use either of these endpoints. If you make a request to the http://bucket.s3.amazonaws.com endpoint, the DNS has sufficient information to route your request directly to the Region where your bucket resides.

  For more information, see Virtual Hosting of Buckets.

• In a path-style URL, the bucket name is not part of the domain (unless you use a Region-specific endpoint). For example:

  • US East (N. Virginia) Region endpoint, http://s3.amazonaws.com/bucket

  • Region-specific endpoint, http://s3-aws-region.amazonaws.com/bucket

  In a path-style URL, the endpoint you use must match the Region in which the bucket resides. For example, if your bucket is in the South America (São Paulo) Region, you must use the http://s3-sa-east-1.amazonaws.com/bucket endpoint. If your bucket is in the US East (N. Virginia) Region, you must use the http://s3.amazonaws.com/bucket endpoint.

Currently, the S3 File System module only allows virtual-hosted-style endpoints. Some non-Amazon S3 implementations only support path-style endpoints, so it would be useful to allow that option to be selected by site administrators.

Proposed resolution

Add a checkbox for using a path-style endpoint to the settings administration page and include that setting when instantiating an S3 client.

Remaining tasks

• Add a "Use path-style endpoint" checkbox to the administration form
• Include the "Use path-style endpoint" setting when an S3 client is instantiated
• Add the "Use path-style endpoint" setting to the configuration form test