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 { #first-steps }

import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

import java.security.GeneralSecurityException;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

/**
 * Versions of TLS that can be offered when negotiating a secure socket. See
 * [javax.net.ssl.SSLSocket.setEnabledProtocols].
 */
enum class TlsVersion(
  @get:JvmName("javaName") val javaName: String,
) {
  TLS_1_3("TLSv1.3"), // 2016.
  TLS_1_2("TLSv1.2"), // 2008.

import jcifs.util.transport.Response;

/**
 * Interface for SMB protocol negotiation response handling.
 * Represents the server's response to a protocol negotiation request, containing negotiated
 * dialect version, security settings, capabilities, and buffer sizes for the SMB connection.
 *
 * @author mbechler
 */
public interface SmbNegotiationResponse extends CommonServerMessageBlock, Response {

    /**

 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package jcifs.smb1.util;

import java.security.MessageDigest;

/**
 * This is an implementation of the HMACT64 keyed hashing algorithm.
 * HMACT64 is defined by Luke Leighton as a modified HMAC-MD5 (RFC 2104)

 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package jcifs.util;

import java.security.MessageDigest;

/**
 * This is an implementation of the HMACT64 keyed hashing algorithm.
 * HMACT64 is defined by Luke Leighton as a modified HMAC-MD5 (RFC 2104)

 */
package jcifs.pac.kerberos;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.util.Enumeration;

import javax.security.auth.kerberos.KerberosKey;

import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;

 */
package okhttp.android.test.sni

import android.os.Build
import android.util.Log
import assertk.assertThat
import assertk.assertions.contains
import assertk.assertions.isEqualTo
import java.security.cert.X509Certificate
import javax.net.ssl.SNIHostName
import javax.net.ssl.SNIServerName
import javax.net.ssl.SSLSocket
import javax.net.ssl.SSLSocketFactory
import okhttp3.DelegatingSSLSocketFactory
import okhttp3.Dns

👆 💪 📨 (& 📨) 📚 📧:

<img src="/img/tutorial/websockets/image04.png">

&amp; 🌐 👫 🔜 ⚙️ 🎏 *️⃣ 🔗.

## ⚙️ `Depends` &amp; 🎏

*️⃣ 🔗 👆 💪 🗄 ⚪️➡️ `fastapi` &amp; ⚙️:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

👫 👷 🎏 🌌 🎏 FastAPI 🔗/*➡ 🛠️*:

{* ../../docs_src/websockets/tutorial002.py hl[66:77,76:91] *}

/// info

///

## **FastAPI** utilitários

**FastAPI** fornece várias ferramentas para cada um desses esquemas de segurança no módulo `fastapi.security` que simplesmente usa esses mecanismos de segurança.

Nos próximos capítulos você irá ver como adicionar segurança à sua API usando essas ferramentas disponibilizadas pelo **FastAPI**.