# API Contract

Base URL prefix: `/api/v1`

Primary implementation modules:
- `backend/app/api/router.py`
- `backend/app/api/routes_health.py`
- `backend/app/api/routes_documents.py`
- `backend/app/api/routes_search.py`
- `backend/app/api/routes_processing_logs.py`
- `backend/app/api/routes_settings.py`

## Authentication And Authorization

- Protected endpoints require `Authorization: Bearer <token>`.
- `ADMIN_API_TOKEN` is required for all privileged access and acts as fail-closed root credential.
- `USER_API_TOKEN` is optional and, when configured, grants access to document endpoints only.
- Authorization matrix:
  - `documents/*`: `admin` or `user`
  - `search/*`: `admin` or `user`
  - `settings/*`: `admin` only
  - `processing/logs/*`: `admin` only

## Health

- `GET /health`
- Purpose: liveness check
- Response: `{ "status": "ok" }`

## Documents

- Access: admin or user token required

### Collection and metadata helpers

- `GET /documents`
  - Query: `offset`, `limit`, `include_trashed`, `only_trashed`, `path_prefix`, `path_filter`, `tag_filter`, `type_filter`, `processed_from`, `processed_to`
  - Response model: `DocumentsListResponse`
- `GET /documents/tags`
  - Query: `include_trashed`
  - Response: `{ "tags": string[] }`
- `GET /documents/paths`
  - Query: `include_trashed`
  - Response: `{ "paths": string[] }`
- `GET /documents/types`
  - Query: `include_trashed`
  - Response: `{ "types": string[] }`
- `POST /documents/content-md/export`
  - Body model: `ContentExportRequest`
  - Response: ZIP stream containing one markdown file per matched document

### Per-document operations

- `GET /documents/{document_id}`
  - Response model: `DocumentDetailResponse`
- `GET /documents/{document_id}/download`
  - Response: original file bytes
- `GET /documents/{document_id}/preview`
  - Response: inline preview stream where browser-supported
- `GET /documents/{document_id}/thumbnail`
  - Response: generated thumbnail image when available
- `GET /documents/{document_id}/content-md`
  - Response: extracted markdown content for one document
- `PATCH /documents/{document_id}`
  - Body model: `DocumentUpdateRequest`
  - Response model: `DocumentResponse`
- `POST /documents/{document_id}/trash`
  - Response model: `DocumentResponse`
- `POST /documents/{document_id}/restore`
  - Response model: `DocumentResponse`
- `DELETE /documents/{document_id}`
  - Behavior: permanent delete, requires document to be trashed first
  - Response: deletion counters
- `POST /documents/{document_id}/reprocess`
  - Response model: `DocumentResponse`
  - Behavior: requeues asynchronous processing task

### Upload

- `POST /documents/upload`
- Multipart form fields:
  - `files[]` (required)
  - `relative_paths[]` (optional)
  - `logical_path` (optional, defaults to `Inbox`)
  - `tags` (optional CSV)
  - `conflict_mode` (`ask`, `replace`, `duplicate`)
- Response model: `UploadResponse`
- Behavior:
  - `ask`: returns `conflicts` if duplicate checksum is detected
  - `replace`: creates new document linked to replaced document id
  - `duplicate`: creates additional document record
  - upload `POST` request rejected with `411` when `Content-Length` is missing
  - `OPTIONS /documents/upload` CORS preflight bypasses upload `Content-Length` enforcement
  - request rejected with `413` when file count, per-file size, or total request size exceeds configured limits

## Search

- Access: admin or user token required

- `GET /search`
- Query: `query` (min length 2), `offset`, `limit`, `include_trashed`, `only_trashed`, `path_filter`, `tag_filter`, `type_filter`, `processed_from`, `processed_to`
- Response model: `SearchResponse`
- Behavior: PostgreSQL full-text and metadata ranking

## Processing Logs

- Access: admin token required

- `GET /processing/logs`
  - Query: `offset`, `limit`, `document_id`
  - Response model: `ProcessingLogListResponse`
  - `limit` is capped by runtime configuration
  - sensitive fields are redacted in API responses
- `POST /processing/logs/trim`
  - Query: optional `keep_document_sessions`, `keep_unbound_entries`
  - Behavior: omitted query values fall back to persisted `/settings.processing_log_retention`
  - query values are capped by runtime retention limits
  - Response: trim counters
- `POST /processing/logs/clear`
  - Response: clear counters

## Settings

- Access: admin token required

- `GET /settings`
  - Response model: `AppSettingsResponse`
  - persisted providers with invalid base URLs are ignored during read sanitization; response falls back to remaining valid providers or secure defaults
- `PATCH /settings`
  - Body model: `AppSettingsUpdateRequest`
  - Response model: `AppSettingsResponse`
  - rejects invalid provider base URLs with `400` when scheme, allowlist, or network safety checks fail
- `POST /settings/reset`
  - Response model: `AppSettingsResponse`
- `PATCH /settings/handwriting`
  - Body model: `HandwritingSettingsUpdateRequest`
  - Response model: `AppSettingsResponse`
- `GET /settings/handwriting`
  - Response model: `HandwritingSettingsResponse`

## Schema Families

Document schemas in `backend/app/schemas/documents.py`:
- `DocumentResponse`
- `DocumentDetailResponse`
- `DocumentsListResponse`
- `UploadConflict`
- `UploadResponse`
- `DocumentUpdateRequest`
- `SearchResponse`
- `ContentExportRequest`

Processing log schemas in `backend/app/schemas/processing_logs.py`:
- `ProcessingLogEntryResponse`
- `ProcessingLogListResponse`

Settings schemas in `backend/app/schemas/settings.py`:
- Provider, task, upload-default, display, processing-log retention, predefined paths or tags, handwriting-style, and legacy handwriting models grouped under `AppSettingsResponse` and `AppSettingsUpdateRequest`.