* 標頭（Header）
    * 查詢參數
    * Cookies，等等。

加上来自 Starlette（包括 **session cookie**）的所有安全特性。

所有的這些都是可重複使用的工具和套件，可以輕鬆與你的系統、資料儲存（Data Stores）、關聯式資料庫（RDBMS）以及非關聯式資料庫（NoSQL）等等整合。


### 依賴注入（Dependency Injection）

FastAPI 有一個使用簡單，但是非常強大的<abbr title='也叫做 "components", "resources", "services", "providers"'><strong>依賴注入</strong></abbr>系統。

* 依賴項甚至可以有自己的依賴，從而形成一個層級或**依賴圖**的結構。
* 所有**自動化處理**都由框架完成。

///

## Configurações em uma dependência { #settings-in-a-dependency }

Em algumas ocasiões, pode ser útil fornecer as configurações a partir de uma dependência, em vez de ter um objeto global `settings` usado em todos os lugares.

	if atEOF {
		return len(data), dropCR(data), nil
	}
	// Request more data.
	return 0, nil, nil
}

// isSpace reports whether the character is a Unicode white space character.
// We avoid dependency on the unicode package, but check validity of the implementation
// in the tests.
func isSpace(r rune) bool {
	if r <= '\u00FF' {
		// Obvious ASCII ones: \t through \r plus space. Plus two Latin-1 oddballs.

Para esto, usamos `security_scopes.scopes`, que contiene una `list` con todos estos scopes como `str`.

{* ../../docs_src/security/tutorial005_an_py310.py hl[130:136] *}

## Árbol de dependencias y scopes { #dependency-tree-and-scopes }

Revisemos de nuevo este árbol de dependencias y los scopes.

## Dependabot PRs

Dependabot will create PRs to update dependencies for several things, and those PRs all look similar, but some are way more delicate than others.

* If the PR is for a direct dependency, so, Dependabot is modifying `pyproject.toml`, **don't merge it**. 😱 Let me check it first. There's a good chance that some additional tweaks or updates are needed.

    Note over dep: Run code up to yield
    opt raise Exception
        dep -->> handler: Raise Exception
        handler -->> client: HTTP error response
    end
    dep ->> operation: Run dependency, e.g. DB session
    opt raise
        operation -->> dep: Raise Exception (e.g. HTTPException)
        opt handle
            dep -->> dep: Can catch exception, raise a new HTTPException, raise other exception

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[21:22] hl[21:22] *}

### Criar uma Dependência de Sessão { #create-a-session-dependency }

Uma **`Session`** é o que armazena os **objetos na memória** e acompanha as alterações necessárias nos dados, para então **usar o `engine`** para se comunicar com o banco de dados.

```console
$ pip install pyjwt

---> 100%
```

</div>

/// info

If you are planning to use digital signature algorithms like RSA or ECDSA, you should install the cryptography library dependency `pyjwt[crypto]`.

You can read more about it in the <a href="https://pyjwt.readthedocs.io/en/latest/installation.html" class="external-link" target="_blank">PyJWT Installation docs</a>.

///

     */
    PathMatcher matcher(Collection<String> defaultIncludes, boolean useDefaultExcludes);

    /**
     * {@return in which context the source files will be used}
     * Not to be confused with dependency scope.
     * The default value is {@code "main"}.
     *
     * @see ProjectScope#MAIN
     */
    default ProjectScope scope() {
        return ProjectScope.MAIN;
    }

    /**

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[21:22] hl[21:22] *}

### Eine Session-Abhängigkeit erstellen { #create-a-session-dependency }