# Simple OAuth2 with Password and Bearer { #simple-oauth2-with-password-and-bearer }

Now let's build from the previous chapter and add the missing parts to have a complete security flow.

## Get the `username` and `password` { #get-the-username-and-password }

We are going to use **FastAPI** security utilities to get the `username` and `password`.

		parities []int
		parity   int
	}{
		// More than simple majority consensus
		mkTest(15, 3, 11),
		// No simple majority consensus
		mkTest(15, 3, 7),
		// Exact simple majority consensus
		mkTest(15, 3, 8),
		// More than simple majority consensus
		mkTest(16, 4, 11),
		// No simple majority consensus
		mkTest(16, 4, 8),
		// Exact simple majority consensus
		mkTest(16, 4, 9),

* external APIs
* authentication and authorization systems
* API usage monitoring systems
* response data injection systems
* etc.

## Simple and Powerful { #simple-and-powerful }

Although the hierarchical dependency injection system is very simple to define and use, it's still very powerful.

You can define dependencies that in turn can define dependencies themselves.

Apart from all the fancy words used here, the **Dependency Injection** system is quite simple.

Just functions that look the same as the *path operation functions*.

But still, it is very powerful, and allows you to declare arbitrarily deeply nested dependency "graphs" (trees).

/// tip

All this might not seem as useful with these simple examples.

But you will see how useful it is in the chapters about **security**.

```
Client #1596980209979 left the chat
```

/// tip

The app above is a minimal and simple example to demonstrate how to handle and broadcast messages to several WebSocket connections.

But keep in mind that, as everything is handled in memory, in a single list, it will only work while the process is running, and will only work with a single process.

In this case the middleware will intercept the incoming request and respond with appropriate CORS headers, and either a `200` or `400` response for informational purposes.

### Simple requests { #simple-requests }

Any request with an `Origin` header. In this case the middleware will pass the request through as normal, but will include appropriate CORS headers on the response.

## More info { #more-info }

    private final long timeoutMillis;

    /**
     * Creates a simple circuit breaker with default settings
     *
     * @param name the circuit breaker name
     */
    public SimpleCircuitBreaker(String name) {
        this(name, 5, 3, 30000L); // 5 failures, 3 successes, 30 second timeout
    }

    /**
     * Creates a simple circuit breaker
     *
     * @param name the circuit breaker name

Here are some examples of when that could make sense:

#### A Simple App { #a-simple-app }

You could want a process manager in the container if your application is **simple enough** that can run it on a **single server**, not a cluster.

#### Docker Compose { #docker-compose }

## Declaring types { #declaring-types }

You just saw the main place to declare type hints. As function parameters.

This is also the main place you would use them with **FastAPI**.

### Simple types { #simple-types }

You can declare all the standard Python types, not only `str`.

You can use, for example:

* `int`
* `float`
* `bool`
* `bytes`

        String lang = "en";

        List<AnalyzeToken> tokens = analyzer.analyze(text, field, lang);

        assertNotNull(tokens);
        assertEquals(8, tokens.size()); // "I'm" is split into "I" and "m" by our simple tokenizer
        assertEquals("Hello", tokens.get(0).getTerm());
        assertEquals("world", tokens.get(1).getTerm());
        assertEquals("How", tokens.get(2).getTerm());