### Einbringen von Abhängigkeiten (Dependency Injection)

FastAPI enthält ein extrem einfach zu verwendendes, aber extrem mächtiges <abbr title='Dependency Injection – Einbringen von Abhängigkeiten: Auch bekannt als Komponenten, Resourcen, Dienste, Dienstanbieter'><strong>Dependency Injection</strong></abbr> System.

* Selbst Abhängigkeiten können Abhängigkeiten haben, woraus eine Hierarchie oder ein **„Graph“ von Abhängigkeiten** entsteht.

### Dependency Injection { #dependency-injection }

FastAPI includes an extremely easy to use, but extremely powerful <abbr title='also known as "components", "resources", "services", "providers"'><strong>Dependency Injection</strong></abbr> system.

* Even dependencies can have dependencies, creating a hierarchy or **"graph" of dependencies**.
* All **automatically handled** by the framework.

### Dependency Injection

FastAPI bao gồm một hệ thống <abbr title='cũng biết đến như là "components", "resources", "services", "providers"'><strong>Dependency Injection</strong></abbr> vô cùng dễ sử dụng nhưng vô cùng mạnh mẽ.

     */
    String getProviderName();
    
    /**
     * Get maximum message size supported
     */
    int getMaxMessageSize();
    
    /**
     * Clean up provider resources
     */
    void shutdown();
}

public enum RdmaAccess {
    LOCAL_READ,
    LOCAL_WRITE,
    REMOTE_READ,
    REMOTE_WRITE,
    MEMORY_BIND
}
```

## 4. Data Structures

   * If the response body is closed before the response body is exhausted, this is invoked at the
   * time it is closed. In such calls [byteCount] is the number of bytes returned to the
   * application. This may be smaller than the resource's byte count if were read to completion.
   *
   * This method is always invoked after [responseBodyStart].
   */
  open fun responseBodyEnd(
    call: Call,
    byteCount: Long,
  ) {
  }

  /**

### Injeção de dependência

FastAPI inclui um sistema de <abbr title='também conhecido como "components", "resources", "services", "providers"'><strong>injeção de dependência</strong></abbr> extremamente fácil de usar, mas extremamente poderoso.

* Mesmo dependências podem ter dependências, criando uma hierarquia ou **"grafo" de dependências**.

        }

        final Map<String, Object> source = new HashMap<>();
        source.put(FieldNames.ARRAY_KEY, key);
        source.put(FieldNames.ARRAY_VALUE, value);
        source.put(FieldNames.TIMESTAMP, DateTimeFormatter.ISO_INSTANT.format(ZonedDateTime.now()));

        addToArrayIndex(arraySettingsIndexName, settingsId, createId(key, value), source);
    }

    /**
     * Delete values.

     *
     * The read timeout is applied to both the TCP socket and for individual read IO operations
     * including on [Source] of the [Response]. The default value is 10 seconds.
     *
     * @see Socket.setSoTimeout
     * @see Source.timeout
     */
    fun readTimeout(
      timeout: Long,
      unit: TimeUnit,
    ) = apply {

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。
* 依賴項不僅能從請求中提取資料，還能**對 API 的路徑操作進行強化**，並自動生成文檔。
* 即使是依賴項中定義的*路徑操作參數*，也會**自動進行驗證**。

    // +---------------------------------------------------------------+
    val length = source.readMedium()
    if (length > INITIAL_MAX_FRAME_SIZE) {
      throw IOException("FRAME_SIZE_ERROR: $length")
    }
    val type = source.readByte() and 0xff
    val flags = source.readByte() and 0xff
    val streamId = source.readInt() and 0x7fffffff // Ignore reserved bit.