OkHttp 3.x. You can use an OkHttp 4.x .jar file with applications or libraries built for OkHttp 3.x.

OkHttp is **not** source-compatible for Kotlin callers, but upgrading should be automatic thanks to
Kotlin’s powerful deprecation features. Most developers should be able to use IntelliJ’s _Code
Cleanup_ for a safe and fast upgrade.


Backwards-Incompatible Changes
------------------------------

For example, if you have a header parameter `save_data` in the code, the expected HTTP header will be `save-data`, and it will show up like that in the docs.

If for some reason you need to disable this automatic conversion, you can do it as well for Pydantic models for header parameters.

{* ../../docs_src/header_param_models/tutorial003_an_py310.py hl[19] *}

/// warning

В этом случае оно будет смонтировано по пути `/subapi`:

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 19] *}

### Проверьте автоматическую документацию API { #check-the-automatic-api-docs }

Теперь запустите команду `fastapi` с вашим файлом:

<div class="termy">

```console
$ fastapi dev main.py

///

/// info | Информация

Чтобы объявить заголовки, важно использовать `Header`, иначе параметры интерпретируются как query-параметры.

///

## Автоматическое преобразование { #automatic-conversion }

`Header` обладает небольшой дополнительной функциональностью в дополнение к тому, что предоставляют `Path`, `Query` и `Cookie`.

And you will still have the same features as seen up to now:

* Great editor support.
* Data conversion from incoming requests.
* Data conversion for response data.
* Data validation.
* Automatic annotation and documentation.

## Other data types { #other-data-types }

Here are some of the additional data types you can use:

* `UUID`:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Centralized resource management for preventing resource leaks.
 * Tracks all AutoCloseable resources and ensures proper cleanup.
 *
 * Features:
 * - Automatic resource cleanup with weak references
 * - Resource leak detection
 * - Resource usage monitoring
 * - Periodic cleanup of abandoned resources
 * - Detailed resource tracking and reporting
 */

/**
 * Explicitly specifies the types that should be used for dependency injection.
 * <p>
 * This annotation allows you to limit which types of a bean should be available
 * for injection. It can be used to prevent unintended automatic binding of implemented
 * interfaces or extended classes.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Typed(ServiceImpl.class)
 * public class ServiceImpl implements Service {
 *     // Implementation
 * }

import com.google.common.cache.TestingCacheLoaders.IncrementingLoader;
import com.google.common.testing.FakeTicker;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests relating to automatic cache refreshing.
 *
 * @author Charles Fry
 */
@NullUnmarked
public class CacheRefreshTest extends TestCase {
  public void testAutoRefresh() {
    FakeTicker ticker = new FakeTicker();

- **`org.codelibs.curl.CurlException`**: Unchecked exception for HTTP errors

### I/O Layer

- **`org.codelibs.curl.io.ContentCache`**: Handles automatic in-memory or on-disk caching of request/response bodies
- **`org.codelibs.curl.io.ContentOutputStream`**: Streaming utilities for efficient content handling

### Key Design Patterns

* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.
    * This will be used by the **automatic docs**.
    * It will also be used by automatic client code generation tools.

But most importantly:

* It will **limit and filter** the output data to what is defined in the return type.