# `Storehouse.Plug.Register`
[🔗](https://github.com/hattoriai/storehouse/blob/v0.2.0/lib/storehouse/plug/register.ex#L1)

Checks the files a browser uploaded straight to the store, signed by
`Storehouse.Plug.Presign`, and gives them to the app: a JSON endpoint in
front of `Storehouse.Batch.register/2`.

    forward "/register", Storehouse.Plug.Register,
      owner: &MyAppWeb.Files.owner/1,
      room: &MyAppWeb.Files.room/1,
      existing: &MyAppWeb.Files.existing/2,
      accept: Storehouse.Check.images(),
      then: &MyAppWeb.Files.registered/2

A `POST` of

    {"uploads": [{"key": "accounts/42/2026/10/…-harbour.jpg", "name": "harbour.jpg"}]}

checks each file in the store by its bytes, then calls `:then` with the
conn and the results (`{:ok, file}`, `{:existing, file}` or
`{:error, code}`, one per upload, in order). It gives what the app
makes of them (its records, in one transaction), as a list of JSON
values, one per upload, which is answered `200` as
`{"uploads": [...]}`. Without `:then`, each result is its file:

    {"uploads": [{"file": {...}}, {"existing": {...}}, {"error": "not_owner"}]}

A key of another owner's file (`:owner`) is refused, and that file left
as it is, so a browser cannot claim another's file by its key.

## Options

  * `:owner`, `:room`, `:existing` - functions of the conn, as for
    `Storehouse.Plug.Presign`.
  * `:then` - a function of the conn and the results that gives the
    JSON value of each.
  * the other options of `Storehouse.Batch.register/2` (`:accept`,
    `:max_bytes`, `:max_pixels`, `:metadata`, `:adapter`, `:max_items`),
    as they are.

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*Consult [api-reference.md](api-reference.md) for complete listing*