# `AttestoPhoenix.RegistrationStore`
[🔗](https://github.com/XukuLLC/attesto_phoenix/blob/v0.19.0/lib/attesto_phoenix/registration_store.ex#L1)

The host-owned dynamic client registration persistence contract
(RFC 7591 §3 / RFC 7592 §2).

The registration controller owns credential generation and protocol framing,
but the client registry is host-owned: it persists a newly registered
client, deletes one during registration management cleanup, and exposes the
stored registration access-token hash for management requests. A host
implements this behaviour and wires each callback into
`AttestoPhoenix.Config`; this module is the contract those keys install and
the recommended production shape.

Each `@callback` corresponds to the identically named `AttestoPhoenix.Config`
key:

  * `register_client/1` (`:register_client`, required when
    `:registration_enabled`)
  * `unregister_client/1` (`:unregister_client`)
  * `client_registration_access_token_hash/1`
    (`:client_registration_access_token_hash`)

# `client`

```elixir
@type client() :: term()
```

The host's opaque client representation.

# `client_registration_access_token_hash`
*optional* 

```elixir
@callback client_registration_access_token_hash(client()) :: String.t() | nil
```

Return the stored hash of the registration access token issued with a dynamic
client (RFC 7592 §2), or `nil`. When the Config key is unset, DELETE requests
fail closed.

# `register_client`

```elixir
@callback register_client(attrs :: map()) :: {:ok, client()} | {:error, term()}
```

Persist a dynamically registered client (RFC 7591 §3.2.1).

Receives the validated, issuance-ready attributes (the at-rest secret hash,
never the plaintext). Returns `{:ok, client}` or `{:error, reason}`; a store
rejection surfaces to the caller as `invalid_client_metadata` rather than a
server fault.

# `unregister_client`
*optional* 

```elixir
@callback unregister_client(client()) :: :ok | {:ok, client()} | {:error, term()}
```

Delete a dynamically registered client during registration management cleanup
(RFC 7592 §2). Returns `:ok`, `{:ok, client}`, or `{:error, reason}`. When
the Config key is unset, DELETE requests to the management endpoint fail
closed.

---

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