///

```Python hl_lines="116-131"
{!> ../../docs_src/security/tutorial004.py!}
```

////

### Technical details about the JWT "subject" `sub`

The JWT specification says that there's a key `sub`, with the subject of the token.

It's optional to use it, but that's where you would put the user's identification, so we are using it here.

	// of them are not local. This situation can never happen and
	// its only a possibility in orchestrated deployments with dynamic
	// DNS. Following code ensures that we treat if one of the endpoint
	// says its local for a given host - it is true for all endpoints
	// for the same host. Following code ensures that this assumption
	// is true and it works in all scenarios and it is safe to assume
	// for a given host.

   *
   * The problem with these is that remove(K, long) has to be done in two phases by definition ---
   * first decrementing to zero, and then removing. putIfAbsent or replace could observe the
   * intermediate zero-state. Ways we could deal with this are:
   *
   * - Don't define any of the ConcurrentMap operations. This is the current state of affairs.
   *
   * - Define putIfAbsent and replace as treating zero and absent identically (as currently

```json
{"message": "Hello World"}
```

...this response will return:

```json
{
  "message": "Hello World"
}
```

Of course, you will probably find much better ways to take advantage of this than formatting JSON. 😉

## Default response class

When creating a **FastAPI** class instance or an `APIRouter` you can specify which response class to use by default.

 * determine addressability of any host, clients of this class will need to perform their own DNS
 * lookups.
 *
 * <p>During construction, names are normalized in two ways:
 *
 * <ol>
 *   <li>ASCII uppercase characters are converted to lowercase.
 *   <li>Unicode dot separators other than the ASCII period ({@code '.'}) are converted to the ASCII
 *       period.
 * </ol>
 *

...so, you are a [team member of FastAPI](./fastapi-people.md#team){.internal-link target=_blank}? Wow, you are so cool! 😎

You can help with everything on [Help FastAPI - Get Help](./help-fastapi.md){.internal-link target=_blank} the same ways as external contributors. But additionally, there are some tasks that only you (as part of the team) can perform.

Here are the general instructions for the tasks you can perform.

Thanks a lot for your help. 🙇

* Keep commits self-contained. Avoid spreading a single change across multiple commits. A single commit should make sense in isolation.

### Testing changes

After making changes, you can test your code in 2 ways:

1. Run tests.
- Run `./gradlew :<subproject>:quickTest` where `<subproject>` is the name of the subproject you've changed. 
- For example: `./gradlew :launcher:quickTest`.

## About proxies with a stripped path prefix

Keep in mind that a proxy with stripped path prefix is only one of the ways to configure it.

Probably in many cases the default will be that the proxy doesn't have a stripped path prefix.

Using Linux containers has several advantages including **security**, **replicability**, **simplicity**, and others.

/// tip

      }
      // reset for next iteration
      numSuccessfulSetCalls.set(0);
      finalResults.clear();
    }
    executor.shutdown();
  }

  // setFuture and cancel() interact in more complicated ways than the other setters.
  public void testSetFutureCancelBash() {
    if (isWindows()) {
      return; // TODO: b/136041958 - Running very slowly on Windows CI.
    }
    final int size = 50;