# atp

AT Protocol boilerplate for Go, extracted from [arabica.social](https://tangled.org/arabica.social/arabica). Covers OAuth flows, PDS client operations, real-time event consumption, session storage, and HTTP middleware.

For integration testing against an ephemeral in-process PDS, see [chrysalis](https://tangled.org/pdewey.com/chrysalis).

## Installation

```sh
go get tangled.org/pdewey.com/atp@latest
```

## Packages

### Root (`atp`)

Core types and clients for the AT Protocol.

- `Client` -- authenticated PDS client for CRUD operations on a user's repository (`CreateRecord`, `GetRecord`, `ListRecords`, `PutRecord`, `DeleteRecord`, `UploadBlob`, `GetBlob`).
- `OAuthApp` -- manages the OAuth flow: login (browser-based and CLI), callback handling, session resumption, and logout. Supports public and localhost (development) client modes.
- `PublicClient` -- unauthenticated access to public atproto APIs (handle resolution, profiles, record reads) with SSRF protection.
- Helpers for AT-URI parsing/building, scope construction, and error handling.

### `jetstream`

WebSocket consumer for the [Jetstream](https://docs.bsky.app/blog/jetstream) relay. Reconnects with exponential backoff, rotates endpoints, optionally decompresses zstd, and persists cursors for resuming after restarts.

### `middleware`

Cookie-based AT Protocol auth middleware. Validates sessions against the OAuth store and injects the authenticated DID into the request context. Also serves the OAuth client metadata endpoint.

### `store/bolt` and `store/sqlite`

Two `oauth.ClientAuthStore` implementations for persisting OAuth sessions and auth request state:

- bolt: BoltDB-backed.
- sqlite: SQLite-backed with automatic schema migration and expired request cleanup.

### `tracing`

OpenTelemetry span helpers for AT Protocol operations (PDS calls, database operations, HTTP handlers). Sets up an OTLP HTTP exporter and returns no-op spans when there is no active trace context.