External Content

What problems arise from redirection?

How does a client suggest a path? Ingest clients vs read clients

Requirements for External Content

A client has a reference to the content location (either file or http), and would like to create a pointer to that content in the server
The server has access to the external content.
Another client does not have direct access to the content, and would like to retrieve it from the server.

The client sends an empty PUT or POST request with Content-Type: message/external-body with the access-type parameter of either url or local-file.
As per RFC2017, the request should include a second Content-type value of the referenced content's type
The server's obligations for the created LDP-NR are the same as if the bytes had been uploaded. For example, when the client performs a HEAD request on the resource, the server must respond with the ETag/Digest/Content-Size/Last-Modified/etc. headers it would include for an internally-managed binary. If the server cannot fulfill those obligation for the proffered URL reference, it should return a 4xx status.
The client retrieves the bytes from the server as if the bytes had been uploaded.
Responses should include a Content-Location header with the URI of the referenced content.
LDP-C that allow creation of LDP-NR with message/external-body should advertise it in Accept-Post
if a POST or PUT with message/external-body is received by an implementation that does not support it, the implementation should respond with HTTP 415 (per https://www.ietf.org/archive/id/draft-wilde-accept-post-03.txt)