# Query Parameters and String Validations

**FastAPI** allows you to declare additional information and validation for your parameters.

Let's take this application as example:

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params_str_validations/tutorial001_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params_str_validations/tutorial001.py!}
```

É por isso que, como dito no site oficial:

> Requests é um dos pacotes Python mais baixados de todos os tempos

O jeito de usar é muito simples. Por exemplo, para fazer uma requisição `GET`, você deveria escrever:

```Python
response = requests.get("http://example.com/some/url")
```

A contra-parte da aplicação FastAPI, *rota de operação*, poderia parecer como:

```Python hl_lines="1"
@app.get("/some/url")

For example, there's an official <a href="https://hub.docker.com/_/python" class="external-link" target="_blank">Python Image</a>.

And there are many other images for different things like databases, for example for:

* <a href="https://hub.docker.com/_/postgres" class="external-link" target="_blank">PostgreSQL</a>

//tensorflow/python/feature_column:vocabulary_testdata
//tensorflow/python/util:nest_test_main_lib
//tensorflow/lite/experimental/examples/lstm:rnn_cell
//tensorflow/lite/experimental/examples/lstm:rnn_cell.py
//tensorflow/lite/experimental/examples/lstm:unidirectional_sequence_lstm_test
//tensorflow/lite/experimental/examples/lstm:unidirectional_sequence_lstm_test.py
//tensorflow/lite/python:interpreter
//tensorflow/lite/python:interpreter_test

                    example: 20
                  page_number:
                    type: integer
                    example: 1
                  record_count:
                    type: integer
                    format: int64
                    example: 31625
                  page_count:
                    type: integer
                    example: 1
                  highlight_params:

 * An immutable representation of a host and port.
 *
 * <p>Example usage:
 *
 * <pre>
 * HostAndPort hp = HostAndPort.fromString("[2001:db8::1]")
 *     .withDefaultPort(80)
 *     .requireBracketsForIPv6();
 * hp.getHost();   // returns "2001:db8::1"
 * hp.getPort();   // returns 80
 * hp.toString();  // returns "[2001:db8::1]:80"
 * </pre>
 *
 * <p>Here are some examples of recognized formats:
 *
 * <ul>
 *   <li>example.com

    checkPublicSuffix("example.com", "example.com")
    checkPublicSuffix("b.example.com", "example.com")
    checkPublicSuffix("a.b.example.com", "example.com")
    checkPublicSuffix("uk.com", null)
    checkPublicSuffix("example.uk.com", "example.uk.com")
    checkPublicSuffix("b.example.uk.com", "example.uk.com")
    checkPublicSuffix("a.b.example.uk.com", "example.uk.com")
    checkPublicSuffix("test.ac", "test.ac")

			domains:  []string{"example.com", "example.com:8080", "[fd00:10:96::7fc7]", "[fd00:10:96::7fc7]:8080"},
			expected: "example.com, [fd00:10:96::7fc7]",
		},
		{
			desc:     "test with more domains",
			domains:  []string{"example.com", "example.com:8080", "www.example.com", "www.example.com:8080", "[fd00:10:96::7fc7]", "[fd00:10:96::7fc7]:8080"},
			expected: "example.com, www.example.com + 1 more...",
		},
	}

///

## OpenID Connect

OpenID Connect is another specification, based on **OAuth2**.

It just extends OAuth2 specifying some things that are relatively ambiguous in OAuth2, to try to make it more interoperable.

For example, Google login uses OpenID Connect (which underneath uses OAuth2).

But Facebook login doesn't support OpenID Connect. It has its own flavor of OAuth2.

### OpenID (not "OpenID Connect")

  @Test
  fun simple() {
    val request = fromArgs("http://example.com").createRequest()
    assertThat(request.method).isEqualTo("GET")
    assertThat(request.url.toString()).isEqualTo("http://example.com/")
    assertThat(request.body).isNull()
  }

  @Test
  @Throws(IOException::class)
  fun put() {
    val request = fromArgs("-X", "PUT", "-d", "foo", "http://example.com").createRequest()
    assertThat(request.method).isEqualTo("PUT")