* URL.
    * Email.
    * UUID.
    * ...và nhiều cái khác.

Tất cả validation được xử lí bằng những thiết lập tốt và mạnh mẽ của **Pydantic**.

### Bảo mật và xác thực

Bảo mật và xác thực đã tích hợp mà không làm tổn hại tới cơ sở dữ liệu hoặc data models.

Tất cả cơ chế bảo mật định nghĩa trong OpenAPI, bao gồm:

* HTTP Basic.

* Một hệ thống **<abbr title="cũng được biết đến như components, resources, providers, services, injectables">Dependency Injection</abbr> vô cùng mạnh mẽ và dễ dàng sử dụng.
* Bảo mật và xác thực, hỗ trợ **OAuth2**(với **JWT tokens**) và **HTTP Basic**.
* Những kĩ thuật nâng cao hơn (nhưng tương đối dễ) để định nghĩa **JSON models lồng nhau** (cảm ơn Pydantic).

# Settings and Environment Variables

In many cases your application could need some external settings or configurations, for example secret keys, database credentials, credentials for email services, etc.

Most of these settings are variable (can change), like database URLs. And many could be sensitive, like secrets.

For this reason it's common to provide them in environment variables that are read by the application.

/// tip

		{"abc//./../def", "def"},
		{"abc/../../././../def", "../../def"},
	}
	for _, test := range cleantests {
		want := test.path != test.result
		got := pathNeedsClean([]byte(test.path))
		if !got {
			t.Logf("no clean: %q", test.path)
		}
		if want && !got {
			t.Errorf("input: %q, want %v, got %v", test.path, want, got)
		}
	}

Because of this, **FastAPI** itself provides an alternative API documentation (using ReDoc), which you can access at <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>:

<img src="/img/tutorial/path-params/image02.png">

So, the thief won't be able to try to use that password in another system (as many users use the same password everywhere, this would be dangerous).

## Install `passlib`

PassLib is a great Python package to handle password hashes.

It supports many secure hashing algorithms and utilities to work with them.

The recommended algorithm is "Bcrypt".

import java.util.Map.Entry;
import java.util.Set;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A {@link Multimap} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Warning:</b> avoid <i>direct</i> usage of {@link ImmutableMultimap} as a type (as with

This is very useful when you need to:

* Have shared logic (the same code logic again and again).
* Share database connections.
* Enforce security, authentication, role requirements, etc.
* And many other things...

All these, while minimizing code repetition.

## First Steps

Let's see a very simple example. It will be so simple that it is not very useful, for now.

    * Je kunt diep **geneste JSON** objecten laten valideren en annoteren.
* **Uitbreidbaar**:
    * Met Pydantic kunnen op maat gemaakte datatypen worden gedefinieerd of je kunt validatie uitbreiden met methoden op een model dat is ingericht met de decorator validator.

 * the permits issued each second steadily increases until it hits the stable rate.
 *
 * <p>As an example, imagine that we have a list of tasks to execute, but we don't want to submit
 * more than 2 per second:
 *
 * <pre>{@code
 * final RateLimiter rateLimiter = RateLimiter.create(2.0); // rate is "2 permits per second"
 * void submitTasks(List<Runnable> tasks, Executor executor) {