/** The underlying index update callback to delegate operations to. */
    protected IndexUpdateCallback indexUpdateCallback;

    /** Factory for creating crawler clients to handle different URL schemes. */
    protected CrawlerClientFactory crawlerClientFactory;

    /**
     * List of URLs to be deleted, cached for batch processing.
     * All access is synchronized via indexUpdateCallback lock.
     */

---

The `APIRouter`s are not "mounted", they are not isolated from the rest of the application.

This is because we want to include their *path operations* in the OpenAPI schema and the user interfaces.

As we cannot just isolate them and "mount" them independently of the rest, the *path operations* are "cloned" (re-created), not included directly.

///

## OAuth2 스코프와 OpenAPI { #oauth2-scopes-and-openapi }

OAuth2 사양은 “스코프(scopes)”를 공백으로 구분된 문자열 목록으로 정의합니다.

각 문자열의 내용은 어떤 형식이든 될 수 있지만, 공백을 포함하면 안 됩니다.

이 스코프들은 “권한”을 나타냅니다.

OpenAPI(예: API 문서)에서는 “security schemes”를 정의할 수 있습니다.

이 security scheme 중 하나가 OAuth2를 사용한다면, 스코프도 선언하고 사용할 수 있습니다.

각 “스코프”는 (공백 없는) 문자열일 뿐입니다.

보통 다음과 같이 특정 보안 권한을 선언하는 데 사용합니다:

* `users:read` 또는 `users:write` 는 흔한 예시입니다.

Python code we can *create an object without an `id`* (`id=None`), assuming the database will *generate it when saving*. SQLModel understands that the database will provide the `id` and *defines the column as a non-null `INTEGER`* in the database schema. See [SQLModel docs on primary keys](https://sqlmodel.tiangolo.com/tutorial/create-db-and-table/#primary-key-id) for details.

* `Field(index=True)` tells SQLModel that it should create a **SQL index** for this column, that would allow faster...

---

Die `APIRouter` sind nicht „gemountet“, sie sind nicht vom Rest der Anwendung isoliert.

Das liegt daran, dass wir deren *Pfadoperationen* in das OpenAPI-Schema und die Benutzeroberflächen einbinden möchten.

Da wir sie nicht einfach isolieren und unabhängig vom Rest „mounten“ können, werden die *Pfadoperationen* „geklont“ (neu erstellt) und nicht direkt einbezogen.

///

 *
 * Sometimes referred to as *protocol*, A URL's scheme describes what mechanism should be used to
 * retrieve the resource. Although URLs have many schemes (`mailto`, `file`, `ftp`), this class only
 * supports `http` and `https`. Use [java.net.URI][URI] for URLs with arbitrary schemes.
 *
 * ### Username and Password
 *
 * Username and password are either present, or the empty string `""` if absent. This class offers

clé primaire afin qu'en Python nous puissions *créer un objet sans `id`* (`id=None`), en supposant que la base *le génère à l'enregistrement*. SQLModel comprend que la base fournira l'`id` et *définit la colonne comme un `INTEGER` non nul* dans le schéma de base. Voir la [documentation SQLModel sur les clés primaires](https://sqlmodel.tiangolo.com/tutorial/create-db-and-table/#primary-key-id) pour plus de détails.

* `Field(index=True)` indique à SQLModel qu'il doit créer un **index SQL**...

Це також був один із перших фреймворків, який генерував спеціальну схему, що оголошувала весь API у JSON.

Він не базувався на таких стандартах, як OpenAPI та JSON Schema. Тому було б непросто інтегрувати його з іншими інструментами, як-от Swagger UI. Але знову ж таки, це була дуже інноваційна ідея.

Він має цікаву незвичайну функцію: використовуючи ту саму структуру, можна створювати API, а також CLI.

- Kubectl explain: when a schema or field includes an externalDocs section, it is now displayed as:
  
  
      EXTERNAL DOCS:
          <description>
          URL: <url>
  
  

#### Configuration Migration

Map Solr configuration to Fess:

| Solr Feature | Fess Equivalent |
|--------------|----------------|
| Solr Core | Fess doesn't use cores; all documents in one index |
| Schema Fields | Define in crawl configuration or use default fields |
| RequestHandlers | Use Fess JSON API with parameters |
| Facet Fields | Configure in Fess search settings |
| Highlighting | Built-in in Fess search results |