Çok basit bir örneğe bakalım. Şimdilik o kadar basit olacak ki pek işe yaramayacak.

Ama bu sayede **Dependency Injection** sisteminin nasıl çalıştığına odaklanabiliriz.

### Bir dependency (bağımlılık) veya "dependable" Oluşturun { #create-a-dependency-or-dependable }

Önce dependency'e odaklanalım.

Bu, bir *path operation function*'ın alabileceği parametrelerin aynısını alabilen basit bir fonksiyondur:

### Bir `Enum` Sınıfı Oluşturalım { #create-an-enum-class }

`Enum`'u import edin ve `str` ile `Enum`'dan miras alan bir alt sınıf oluşturun.

	// Empirically (at least on the Windows Server 2013 builder),
	// the kernel is arbitrarily okay with < 248 bytes. That
	// matches what the docs above say:
	// "When using an API to create a directory, the specified
	// path cannot be so long that you cannot append an 8.3 file
	// name (that is, the directory name cannot exceed MAX_PATH
	// minus 12)." Since MAX_PATH is 260, 260 - 12 = 248.
	//

    }

    @Test
    public void test_AllHttpMethodFactories() {
        // ## Test that all factory methods create requests with correct methods ##

        // ## Act & Assert ##
        assertEquals(Method.GET, Curl.get("http://test.com").method());
        assertEquals(Method.POST, Curl.post("http://test.com").method());

 * dates.
 *
 * This class trims whitespace from values. It never returns values with leading or trailing
 * whitespace.
 *
 * Instances of this class are immutable. Use [Builder] to create instances.
 */
@Suppress("NAME_SHADOWING")
class Headers internal constructor(
  internal val namesAndValues: Array<String>,
) : Iterable<Pair<String, String>> {

      long v;
      if ((as = cells) != null && (n = as.length) > 0) {
        if ((a = as[(n - 1) & h]) == null) {
          if (busy == 0) { // Try to attach new Cell
            Cell r = new Cell(x); // Optimistically create
            if (busy == 0 && casBusy()) {
              boolean created = false;
              try { // Recheck under lock
                Cell[] rs;
                int m, j;

 * easier.
 *
 * @author Jesse Wilson
 * @author Luke Sandberg
 * @since 9.0 (in 1.0 as {@code com.google.common.base.Service})
 */
@DoNotMock("Create an AbstractIdleService")
@J2ktIncompatible
@GwtIncompatible
public interface Service {
  /**
   * If the service state is {@link State#NEW}, this initiates service startup and returns

      if (result) {
        executionList.execute();
      }
      return result;
    }

    /**
     * Following the contract of {@link AbstractQueuedSynchronizer} we create a private subclass to
     * hold the synchronizer. This synchronizer is used to implement the blocking and waiting calls
     * as well as to handle state changes in a thread-safe manner. The current state of the future

///

## Update the dependencies { #update-the-dependencies }

Now we are going to update our dependencies.

We want to get the `current_user` *only* if this user is active.

So, we create an additional dependency `get_current_active_user` that in turn uses `get_current_user` as a dependency.

Both of these dependencies will just return an HTTP error if the user doesn't exist, or if is inactive.

```

</div>

Он также включен при установке набора `all` с:

<div class="termy">

```console
$ pip install "fastapi[all]"
---> 100%
```

</div>

### Создание объекта `Settings` { #create-the-settings-object }

Импортируйте `BaseSettings` из Pydantic и создайте подкласс, очень похожий на Pydantic‑модель.