///

## Override the default exception handlers { #override-the-default-exception-handlers }

**FastAPI** has some default exception handlers.

These handlers are in charge of returning the default JSON responses when you `raise` an `HTTPException` and when the request has invalid data.

You can override these exception handlers with your own.

        if (logger.isDebugEnabled()) {
            logger.debug("Loaded CorsHandler: origin={}", origin);
        }
        handerMap.put(origin, handler);
    }

    /**
     * Gets the CORS handler for the specified origin.
     * If no specific handler is found, returns the wildcard handler.
     *
     * @param origin the origin to look up
     * @return the CORS handler for the origin, or null if none found
     */

        }
    }

    /**
     * Loads protocol handlers from the specified base package by scanning for
     * Handler classes in subpackages and registering them as web or file protocols
     * based on their PROTOCOL_TYPE field.
     *
     * @param basePackage the base package to scan for protocol handlers
     */
    protected void loadProtocols(final String basePackage) {

This was changed in version 0.110.0 to fix unhandled memory consumption from forwarded exceptions without a handler (internal server errors), and to make it consistent with the behavior of regular Python code.

            filterPanel: $('#filterPanel')
        };

        bindEvents();
        autoResizeTextarea();
        updateCharCount();
        showStatus('ready');
    }

    /**
     * Bind event handlers
     */
    function bindEvents() {
        elements.sendBtn.on('click', sendMessage);

        elements.chatInput.on('keydown', function(e) {

app = SomeASGIApp()

new_app = UnicornMiddleware(app, some_config="rainbow")
```

But FastAPI (actually Starlette) provides a simpler way to do it that makes sure that the internal middlewares handle server errors and custom exception handlers work properly.

For that, you use `app.add_middleware()` (as in the example for CORS).

```Python
from fastapi import FastAPI
from unicorn import UnicornMiddleware

app = FastAPI()

    /**
     * Dispatches an event to all registered handlers for the event name.
     *
     * @param event the event to dispatch.
     */
    protected void dispatchEvent(final EventInfo event) {
        final List<Consumer<EventInfo>> handlers = eventHandlers.get(event.name);
        if (handlers != null) {
            for (final Consumer<EventInfo> handler : handlers) {
                try {

おそらくコードの中で直接使用する必要はないでしょう。

しかし、高度なシナリオのために必要な場合には、カスタムヘッダーを追加することができます:

{* ../../docs_src/handling_errors/tutorial002_py310.py hl[14] *}

## カスタム例外ハンドラのインストール { #install-custom-exception-handlers }

カスタム例外ハンドラは[Starletteと同じ例外ユーティリティ](https://www.starlette.dev/exceptions/)を使用して追加することができます。

あなた（または使用しているライブラリ）が`raise`するかもしれないカスタム例外`UnicornException`があるとしましょう。

そして、この例外をFastAPIでグローバルに処理したいと思います。

    }

    private static final Logger logger = LogManager.getLogger(QueryProcessor.class);

    /**
     * Map of query commands indexed by query class simple names.
     * Used to lookup appropriate command handlers for different query types.
     */
    protected Map<String, QueryCommand> queryCommandMap = new HashMap<>();

    /**
     * List of filters that will be applied during query processing.

      advanced/conditional-openapi.md: how-to/conditional-openapi.md
      advanced/extending-openapi.md: how-to/extending-openapi.md
      advanced/testing-database.md: how-to/testing-database.md
  mkdocstrings:
    handlers:
      python:
        options:
          extensions:
          - griffe_typingdoc
          show_root_heading: true
          show_if_no_docstring: true
          preload_modules:
          - httpx