What is the RESTful way to add an untitled item to a set?

Say I want to write an interface exposing the set of books a user has read. Since I want URIs to be human-readable, they'll be of the form /books/War-and-Peace. Adding a book to the set seems like a PUT operation, as it 1) creates a new resource, and 2) is idempotent, since a set cannot have duplicate elements. However, the PUT method requires the client to know the URI of the resource to be cr开发者_运维技巧eated, which must be calculated on the server in this case, since there may be multiple books with the same title, which would be represented as /books/War-and-Peace and /books/War-and-Peace-2. A hacky solution, of course, is to use POST, which is allowed to create new resources, but is not guaranteed to be idempotent.

My solution is the following:

1. The client PUTs to /book-hashes/<hash>, where <hash> is a hash of the book object.
2. The server creates a reference to the object at both that URI and /books/<title>.
3. The server issues a 303 See Other status code pointing to /books/<hash>.
4. The client GETs /book-hashes/<hash>.
5. The server responds with a 301 Moved Permanently, pointing to /books/<title>.
6. The client GETs /books/<title> and stores it as the new URI for the book resource.
7. The server deletes /book-hashes/<hash>.

Is this a legitimate REST solution? Has anyone solved the problem a different way?

There's nothing wrong with using POST here. POST is commonly used to "add" things and then return the URI of the created resource.

So

POST /books?title=War-and-Peace

303 
Location: /books/War-and-Peace-2

How about?

GET /BookSlug?title=War%20and%20Peace
=>
200 OK
Content-Type: text/plain

war-and-peace

followed by

PUT /Book/war-and-peace
<BookContent>
=>
201 Created