### Внедрение зависимостей { #dependency-injection }

FastAPI включает в себя чрезвычайно простую в использовании, но чрезвычайно мощную систему <abbr title='известную как: "components", "resources", "services", "providers"'><strong>Внедрения зависимостей</strong></abbr>.

* Даже зависимости могут иметь зависимости, создавая иерархию или **«граф» зависимостей**.
* Всё **автоматически обрабатывается** фреймворком.

  }

  private void doExtensiveTest(String resourceName) throws IOException {
    Splitter splitter = Splitter.on(CharMatcher.whitespace());
    URL url = getClass().getResource(resourceName);
    for (String line : Resources.readLines(url, UTF_8)) {
      Iterator<String> iterator = splitter.split(line).iterator();
      String input = iterator.next();
      String expectedOutput = iterator.next();
      assertFalse(iterator.hasNext());

    * Cookies, 等等。

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

所有的这些都是可复用的工具和组件，可以轻松与你的系统，数据仓库，关系型以及 NoSQL 数据库等等集成。



### 依赖注入

FastAPI 有一个使用非常简单，但是非常强大的<abbr title='也叫做 "components", "resources", "services", "providers"'><strong>依赖注入</strong></abbr>系统。

* 甚至依赖也可以有依赖，创建一个层级或者**“图”依赖**。
* 所有**自动化处理**都由框架完成。
* 所有的依赖关系都可以从请求中获取数据，并且**增加了路径操作**约束和自动文档生成。
* 即使在依赖项中被定义的*路径操作* 也会**自动验证**。

```
~ mc admin config set alias/ scanner
KEY:

        main.java.srcDirs.forEach {
            outgoing.artifact(it)
        }
        main.groovy.srcDirs.forEach {
            outgoing.artifact(it)
        }
        main.resources.srcDirs.forEach {
            outgoing.artifact(it)
        }
        pluginManager.withPlugin("org.jetbrains.kotlin.jvm") {
            kotlinMainSourceSet.srcDirs.forEach {
                outgoing.artifact(it)

 *
 * <p>{@link #setDefault} allows subclasses to specify default values for types.
 *
 * <p>This class incurs IO because it scans the classpath and reads classpath resources.
 *
 * @author Ben Yu
 * @since 14.0
 */
// TODO: Switch to JUnit 4 and use @Parameterized and @BeforeClass
// Note: @Test annotations are deliberate, as some subclasses specify @RunWith(JUnit4).

}

/**
 * We have some "shared" host where a Linux build agent and a Windows build agent
 * both run on the same bare metal. Some builds require exclusive access to the
 * hardware resources (e.g. performance test).
 */
fun Requirements.requiresNotSharedHost() {
    doesNotContain("agent.host.type", "shared")
}

/**
 * This is an undocumented location that forbids anonymous access.

```
/items/foo
```

/// info

A "path" is also commonly called an "endpoint" or a "route".

///

While building an API, the "path" is the main way to separate "concerns" and "resources".

#### Operation { #operation }

"Operation" here refers to one of the HTTP "methods".

One of:

* `POST`
* `GET`
* `PUT`
* `DELETE`

...and the more exotic ones:

// Every 10 seconds a space character is sent.
// keepHTTPReqResponseAlive will wait for the returned body to be read before starting the ticker.
// The returned function should always be called to release resources.
// An optional error can be sent which will be picked as text only error,
// without its original type by the receiver.
// waitForHTTPResponse should be used to the receiving side.

class DefaultModelValidatorTest {

    private ModelValidator validator;

    private Model read(String pom) throws Exception {
        String resource = "/poms/validation/" + pom;
        try (InputStream is = getClass().getResourceAsStream(resource)) {
            assertNotNull(is, "missing resource: " + resource);
            return new Model(new MavenStaxReader().read(is));
        }
    }