## 技術細節 { #technical-details }

FastAPI 內建實作了一些 SSE 的最佳實務。

- 當 15 秒內沒有任何訊息時，傳送一次**「保活」`ping` 註解**，以避免某些代理伺服器關閉連線；此作法源自於[HTML 規範：Server-Sent Events](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes)中的建議。
- 設定 `Cache-Control: no-cache` 標頭，以**防止快取**串流內容。
- 設定特殊標頭 `X-Accel-Buffering: no`，以**避免**在像 Nginx 這類代理中被**緩衝**。

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

import java.security.GeneralSecurityException;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.spec.SecretKeySpec;
import javax.security.auth.kerberos.KerberosKey;
import javax.security.auth.kerberos.KerberosPrincipal;

import org.junit.jupiter.api.Test;

/**
 * Tests for the PacMac class.
 */

		return objInfo.ETag
	}

	if crypto.SSECopy.IsRequested(headers) {
		key, err = crypto.SSECopy.ParseHTTP(headers)
		if err != nil {
			return objInfo.ETag
		}
	}

	// As per AWS S3 Spec, ETag for SSE-C encrypted objects need not be MD5Sum of the data.
	// Since server side copy with same source and dest just replaces the ETag, we save

- Envoyer un commentaire **« keep alive » `ping`** toutes les 15 secondes quand aucun message n’a été émis, pour éviter que certains proxys ne ferment la connexion, comme suggéré dans la [Spécification HTML : Server-Sent Events](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes).
- Définir l’en-tête `Cache-Control: no-cache` pour **empêcher la mise en cache** du flux.

			}
			return result, toObjectErr(err, bucket, object)
		}
		break
	}

	for i := range uploadIDs {
		uploadIDs[i] = strings.TrimSuffix(uploadIDs[i], SlashSeparator)
	}

	// S3 spec says uploadIDs should be sorted based on initiated time, we need
	// to read the metadata entry.
	var uploads []MultipartInfo

	populatedUploadIDs := set.NewStringSet()

	for _, uploadID := range uploadIDs {

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;

import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import jcifs.CIFSUnsupportedCryptoException;

/**
 * Cryptographic utility class providing encryption and decryption functionality for jCIFS.

- Надсилати **коментар «keep alive» `ping`** кожні 15 секунд, коли не було жодного повідомлення, щоб запобігти закриттю з'єднання деякими проксі, як рекомендовано у [Специфікації HTML: Події, надіслані сервером](https://html.spec.whatwg.org/multipage/server-sent-events.html#authoring-notes).
- Встановити заголовок `Cache-Control: no-cache`, щоб **запобігти кешуванню** потоку.

import assertk.assertions.isFalse
import assertk.assertions.isNull
import assertk.assertions.isTrue
import java.math.BigInteger
import java.security.KeyFactory
import java.security.spec.PKCS8EncodedKeySpec
import java.security.spec.X509EncodedKeySpec
import java.text.SimpleDateFormat
import java.util.Date
import java.util.TimeZone
import okhttp3.tls.HeldCertificate
import okhttp3.tls.decodeCertificatePem

 */
package jcifs.internal.smb2;

import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.util.concurrent.locks.ReentrantLock;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.internal.CommonServerMessageBlock;
import jcifs.internal.SMBSigningDigest;
import jcifs.internal.util.SMBUtil;

 * </ul>
 *
 * <p>For performance reasons the only currently supported character encoding of this class is
 * UTF-8.
 *
 * <p><b>Note:</b> This escaper produces <a
 * href="https://url.spec.whatwg.org/#percent-encode">uppercase</a> hexadecimal sequences.
 *
 * @author David Beaumont
 * @since 15.0
 */
@GwtCompatible
public final class PercentEscaper extends UnicodeEscaper {