# OpenAPI Webhooks { #openapi-webhooks }

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

     * Provides a hint for how many values will be associated with each key newly added to the
     * builder after this call. This does not change semantics, but may improve performance if
     * {@code expectedValuesPerKey} is a good estimate.
     *
     * <p>This may be called more than once; each newly added key will use the most recent call to
     * {@link #expectedValuesPerKey} as its hint.
     *

        // Initialize without container
        emptyGenerator = new EmptyGenerator();

        // Test that destroy method can be called without error
        emptyGenerator.destroy();
        // Call destroy multiple times to ensure it's safe
        emptyGenerator.destroy();
        emptyGenerator.destroy();
    }

    @Test
    public void test_isAvailable() {
        // Initialize without container

    assertThrows(IllegalArgumentException.class, () -> escapeAsString(SIMPLE_ESCAPER, test));
  }

  @SuppressWarnings("nullness") // test of bogus call
  public void testNullInput() {
    UnicodeEscaper e = SIMPLE_ESCAPER;
    assertThrows(NullPointerException.class, () -> e.escape((String) null));
  }

  public void testBadStrings() {

    Method method = getTestSubscriberMethod("recordingMethod");
    Subscriber subscriber = Subscriber.create(bus, this, method);

    subscriber.invokeSubscriberMethod(FIXTURE_ARGUMENT);

    assertTrue("Subscriber must call provided method", methodCalled);
    assertTrue(
        "Subscriber argument must be exactly the provided object.",
        methodArgument == FIXTURE_ARGUMENT);
  }

	return &Reader{
		args:       args,
		decoder:    d,
		valueCh:    d.Stream(),
		readCloser: readCloser,
	}
}

// syncReadCloser will wrap a readcloser and make it safe to call Close while
// reads are running.
type syncReadCloser struct {
	rc io.ReadCloser
	mu sync.Mutex
}

func (pr *syncReadCloser) Read(p []byte) (n int, err error) {

     */
    @Nonnull
    Optional<Source> locate(@Nonnull Path dir);

    /**
     * Parse the model obtained previously by a previous call to {@link #locate(Path)}.
     *
     * @param source the source to parse, never {@code null}
     * @param options possible parsing options, may be {@code null}
     * @return the parsed {@link Model}, never {@code null}

# 调试 { #debugging }

你可以在编辑器中连接调试器，例如使用 Visual Studio Code 或 PyCharm。

## 调用 `uvicorn` { #call-uvicorn }

在你的 FastAPI 应用中直接导入 `uvicorn` 并运行：

{* ../../docs_src/debugging/tutorial001_py310.py hl[1,15] *}

### 关于 `__name__ == "__main__"` { #about-name-main }

`__name__ == "__main__"` 的主要目的是使用以下代码调用文件时执行一些代码：

<div class="termy">

```console
$ python myapp.py
```

</div>

而当其它文件导入它时并不会被调用，像这样：

```Python

	columns := make([]string, 0, len(mapValues))

	// when the length of mapValues is zero,return directly here
	// no need to call stmt.SelectAndOmitColumns method
	if len(mapValues) == 0 {
		stmt.AddError(gorm.ErrEmptySlice)
		return
	}

	var (
		result                    = make(map[string][]interface{}, len(mapValues))

// for os.OpenFile().
func LockedOpenFile(path string, flag int, perm os.FileMode) (*LockedFile, error) {
	return lockedOpenFile(path, flag, perm, syscall.F_SETLKW)
}

// Open - Call os.OpenFile
func Open(path string, flag int, perm os.FileMode) (*os.File, error) {
	return os.OpenFile(path, flag, perm)