建置即時 WebSocket 用戶端 in AWS AppSync - AWS AppSync GraphQL

本文為英文版的機器翻譯版本,如內容有任何歧義或不一致之處,概以英文版為準。

建置即時 WebSocket 用戶端 in AWS AppSync

AWS AppSync 的即時 WebSocket 用戶端可透過多步驟程序啟用 GraphQL 訂閱。用戶端會先建立與 AWS AppSync 即時端點的 WebSocket 連線、傳送連線初始化訊息,並等待確認。成功連線後,用戶端會透過傳送具有唯一 IDs和 GraphQL 查詢的開始訊息來註冊訂閱。 AWS AppSync 會使用確認訊息來確認成功訂閱。然後,用戶端會接聽由對應變動觸發的訂閱事件。為了維持連線, AWS AppSync 會定期傳送保持連線訊息。完成後,用戶端會透過傳送停止訊息來取消註冊訂閱。此系統在單一 WebSocket 連線上支援多個訂閱,並容納各種授權模式,包括 API 金鑰、Amazon Cognito 使用者集區、IAM 和 Lambda。

GraphQL 訂閱的即時 WebSocket 用戶端實作

下列序列圖和步驟顯示 WebSocket 用戶端、HTTP 用戶端和 AWS AppSync 之間的即時訂閱工作流程。

Sequence diagram showing WebSocket client, AppSync endpoints, and HTTP client interactions for real-time subscriptions.
  1. 用戶端會與 AWS AppSync 即時端點建立 WebSocket 連線。如果存在網路錯誤,用戶端應該執行抖動的指數輪詢。如需詳細資訊,請參閱 AWS 架構部落格上的指數退避和抖動

  2. 成功建立 WebSocket 連線後,用戶端會傳送訊息connection_init

  3. 用戶端等待來自 AWS AppSync connection_ack 的訊息。此訊息包含 connectionTimeoutMs 參數,這是 "ka"(keep-alive) 訊息的最大等待時間,以毫秒為單位。

  4. AWS AppSync 會定期"ka"傳送訊息。用戶端會追蹤收到每則"ka"訊息的時間。如果用戶端未在connectionTimeoutMs幾毫秒內收到"ka"訊息,用戶端應該關閉連線。

  5. 用戶端會透過傳送訂閱訊息來註冊 start 訂閱。單一 WebSocket 連線支援多個訂閱,即使它們處於不同的授權模式。

  6. 用戶端等待 AWS AppSync 傳送訊息start_ack以確認訂閱成功。如果發生錯誤, AWS AppSync 會傳回"type": "error"訊息。

  7. 用戶端會接聽訂閱事件,這些事件會在呼叫對應的變動後傳送。查詢和變動通常會透過 https:// 傳送至 AWS AppSync GraphQL 端點。訂閱會使用安全的 WebSocket () 流經 AWS AppSync 即時端點wss://

  8. 用戶端會透過傳送訂閱訊息來取消註冊 stop 訂閱。

  9. 取消註冊所有訂閱並檢查沒有透過 WebSocket 傳輸的訊息後,用戶端可以斷開與 WebSocket 的連線。

建立 WebSocket 連線的交握詳情

若要使用 AWS AppSync 連接和啟動成功的交握,WebSocket 用戶端需要下列項目:

  • The AWS AppSync 即時端點

  • 包含 headerpayload 參數的查詢字串:

    • header:包含與 AWS AppSync 端點和授權相關的資訊。這是來自字串化 JSON 物件的 base64 編碼字串。JSON 對象內容取決於授權模式。

    • payload:Base64-encoded字串payload

透過這些要求,WebSocket 用戶端可以連線至 URL,其中包含具有查詢字串的即時端點,使用 graphql-ws做為 WebSocket 通訊協定。

從 GraphQL 端點探索 即時端點

通訊協定和網域中的 AWS AppSync GraphQL 端點和 AWS AppSync 即時端點略有不同。您可以使用 AWS Command Line Interface (AWS CLI) 命令 擷取 GraphQL 端點aws appsync get-graphql-api

AWS AppSync GraphQL 端點:

https://example1234567890000.appsync-api.us-east-1.amazonaws.com/graphql

AWS AppSync 即時端點:

wss://example1234567890000.appsync-realtime-api.us-east-1.amazonaws.com/graphql

應用程式可以使用任何 HTTP 用戶端來連接 AWS AppSync GraphQL 端點 (https://) 進行查詢和變更。應用程式可以使用訂閱的任何 WebSocket 用戶端連線到 AWS AppSync 即時端點 (wss://)。

使用自訂網域名稱,您可以使用單一網域與兩個端點互動。例如,如果您將 api.example.com設定為自訂網域,則可以使用這些 URLs 與 GraphQL 和即時端點互動:

AWS AppSync 自訂網域 GraphQL 端點:

https://api.example.com/graphql

AWS AppSync 自訂網域即時端點:

wss://api.example.com/graphql/realtime

以 AWS AppSync API 授權模式為基礎的標頭參數格式

連線查詢字串中使用的header物件格式會因 AWS AppSync API 授權模式而有所不同。物件中的 host 欄位是指 AWS AppSync GraphQL 端點,即使對即時端點進行wss://呼叫,它也會用來驗證連線。若要啟動交握並建立授權連線,payload 應該是空的 JSON 物件。

API 金鑰

標頭內容

  • "host": <string>: AWS AppSync GraphQL 端點的主機或您的自訂網域名稱。

  • "x-api-key": <string>:為 AWS AppSync API 設定的 API 金鑰。

範例

{ "host":"example1234567890000.appsync-api.us-east-1.amazonaws.com", "x-api-key":"da2-12345678901234567890123456" }

承載內容

{}

請求 URL

wss://example1234567890000.appsync-realtime-api.us-east-1.amazonaws.com/graphql?header=eyJob3N0IjoiZXhhbXBsZTEyMzQ1Njc4OTAwMDAuYXBwc3luYy1hcGkudXMtZWFzdC0xLmFtYXpvbmF3cy5jb20iLCJ4LWFtei1kYXRlIjoiMjAyMDA0MDFUMDAxMDEwWiIsIngtYXBpLWtleSI6ImRhMi16NHc0NHZoczV6Z2MzZHRqNXNranJsbGxqaSJ9&payload=e30=

Amazon Cognito 使用者集區和 OpenID 連線 (OIDC)

標頭內容:

  • "Authorization": <string>:JWT ID 字符。標頭可以使用 Bearer 方案

  • "host": <string>: AWS AppSync GraphQL 端點的主機或您的自訂網域名稱。

範例:

{ "Authorization":"eyEXAMPLEiJjbG5xb3A5eW5MK09QYXIrMTJHWEFLSXBieU5WNHhsQjEXAMPLEnM2WldvPSIsImFsZyI6IlEXAMPLEn0.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.B4EXAMPLEFNpJ6ikVp7e6DRee95V6Qi-zEE2DJH7sHOl2zxYi7f-SmEGoh2AD8emxQRYajByz-rE4Jh0QOymN2Ys-ZIkMpVBTPgu-TMWDyOHhDUmUj2OP82yeZ3wlZAtr_gM4LzjXUXmI_K2yGjuXfXTaa1mvQEBG0mQfVd7SfwXB-jcv4RYVi6j25qgow9Ew52ufurPqaK-3WAKG32KpV8J4-Wejq8t0c-yA7sb8EnB551b7TU93uKRiVVK3E55Nk5ADPoam_WYE45i3s5qVAP_-InW75NUoOCGTsS8YWMfb6ecHYJ-1j-bzA27zaT9VjctXn9byNFZmEXAMPLExw", "host":"example1234567890000.appsync-api.us-east-1.amazonaws.com" }

承載內容:

{}

請求 URL:

wss://example1234567890000.appsync-realtime-api.us-east-1.amazonaws.com/graphql?header=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&payload=e30=

IAM

標頭內容

  • "accept": "application/json, text/javascript":常數 <string> 參數。

  • "content-encoding": "amz-1.0":常數 <string> 參數。

  • "content-type": "application/json; charset=UTF-8":常數 <string> 參數。

  • "host": <string>:這是 AWS AppSync GraphQL 端點的主機。

    • "x-amz-date": <string>:時間戳記必須是 UTC 和下列 ISO 8601 格式:YYYYMMDD'T'HHMMSS'Z'。例如,20150830T123600Z 是有效的時間戳記。不包含時間戳記的毫秒數。如需詳細資訊,請參閱 中的 Signature 第 4 版中的處理日期AWS 一般參考

    • "X-Amz-Security-Token": <string>: AWS 工作階段字符,使用臨時安全登入資料時需要。如需詳細資訊,請參閱《IAM 使用者指南》中的搭配使用暫時憑證與 AWS 資源

    • "Authorization": <string>: AWS AppSync 端點的簽章第 4 版 (SigV4) 簽署資訊。如需簽署程序的詳細資訊,請參閱 中的任務 4:將簽章新增至 HTTP 請求AWS 一般參考

SigV4 簽署 HTTP 請求包含正式 URL,這是/connect附加 的 AWS AppSync GraphQL 端點。服務端點 AWS 區域與您使用 AWS AppSync API 的區域相同,且服務名稱為 'appsync'。要簽署的 HTTP 請求如下:

{ url: "https://example1234567890000.appsync-api.us-east-1.amazonaws.com/graphql/connect", data: "{}", method: "POST", headers: { "accept": "application/json, text/javascript", "content-encoding": "amz-1.0", "content-type": "application/json; charset=UTF-8", } }

範例

{ "accept": "application/json, text/javascript", "content-encoding": "amz-1.0", "content-type": "application/json; charset=UTF-8", "host": "example1234567890000.appsync-api.us-east-1.amazonaws.com", "x-amz-date": "20200401T001010Z", "X-Amz-Security-Token": "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", "Authorization": "AWS4-HMAC-SHA256 Credential=XXXXXXXXXXXXXXXXXXX/20200401/us-east-1/appsync/aws4_request, SignedHeaders=accept;content-encoding;content-type;host;x-amz-date;x-amz-security-token, Signature=83EXAMPLEbcc1fe3ee69f75cd5ebbf4cb4f150e4f99cec869f149c5EXAMPLEdc" }

承載內容

{}

請求 URL

wss://example1234567890000.appsync-realtime-api.us-east-1.amazonaws.com/graphql?header=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&payload=e30=

若要使用自訂網域簽署請求:

{ url: "https://api.example.com/graphql/connect", data: "{}", method: "POST", headers: { "accept": "application/json, text/javascript", "content-encoding": "amz-1.0", "content-type": "application/json; charset=UTF-8", } }

範例

{ "accept": "application/json, text/javascript", "content-encoding": "amz-1.0", "content-type": "application/json; charset=UTF-8", "host": "api.example.com", "x-amz-date": "20200401T001010Z", "X-Amz-Security-Token": "AgEXAMPLEZ2luX2VjEAoaDmFwLXNvdXRoZWFEXAMPLEcwRQIgAh97Cljq7wOPL8KsxP3YtDuyc/9hAj8PhJ7Fvf38SgoCIQDhJEXAMPLEPspioOztj++pEagWCveZUjKEn0zyUhBEXAMPLEjj//////////8BEXAMPLExODk2NDgyNzg1NSIMo1mWnpESWUoYw4BkKqEFSrm3DXuL8w+ZbVc4JKjDP4vUCKNR6Le9C9pZp9PsW0NoFy3vLBUdAXEXAMPLEOVG8feXfiEEA+1khgFK/wEtwR+9zF7NaMMMse07wN2gG2tH0eKMEXAMPLEQX+sMbytQo8iepP9PZOzlZsSFb/dP5Q8hk6YEXAMPLEYcKZsTkDAq2uKFQ8mYUVA9EtQnNRiFLEY83aKvG/tqLWNnGlSNVx7SMcfovkFDqQamm+88y1OwwAEYK7qcoceX6Z7GGcaYuIfGpaX2MCCELeQvZ+8WxEgOnIfz7GYvsYNjLZSaRnV4G+ILY1F0QNW64S9Nvj+BwDg3ht2CrNvpwjVYlj9U3nmxE0UG5ne83LL5hhqMpm25kmL7enVgw2kQzmU2id4IKu0C/WaoDRuO2F5zE63vJbxN8AYs7338+4B4HBb6BZ6OUgg96Q15RA41/gIqxaVPxyTpDfTU5GfSLxocdYeniqqpFMtZG2n9d0u7GsQNcFkNcG3qDZm4tDo8tZbuym0a2VcF2E5hFEgXBa+XLJCfXi/77OqAEjP0x7Qdk3B43p8KG/BaioP5RsV8zBGvH1zAgyPha2rN70/tT13yrmPd5QYEfwzexjKrV4mWIuRg8NTHYSZJUaeyCwTom80VFUJXG+GYTUyv5W22aBcnoRGiCiKEYTLOkgXecdKFTHmcIAejQ9Welr0a196Kq87w5KNMCkcCGFnwBNFLmfnbpNqT6rUBxxs3X5ntX9d8HVtSYINTsGXXMZCJ7fnbWajhg/aox0FtHX21eF6qIGT8j1z+l2opU+ggwUgkhUUgCH2TfqBj+MLMVVvpgqJsPKt582caFKArIFIvO+9QupxLnEH2hz04TMTfnU6bQC6z1buVe7h+tOLnh1YPFsLQ88anib/7TTC8k9DsBTq0ASe8R2GbSEsmO9qbbMwgEaYUhOKtGeyQsSJdhSk6XxXThrWL9EnwBCXDkICMqdntAxyyM9nWsZ4bL9JHqExgWUmfWChzPFAqn3F4y896UqHTZxlq3WGypn5HHcem2Hqf3IVxKH1inhqdVtkryEiTWrI7ZdjbqnqRbl+WgtPtKOOweDlCaRs3R2qXcbNgVhleMk4IWnF8D1695AenU1LwHjOJLkCjxgNFiWAFEPH9aEXAMPLExA==", "Authorization": "AWS4-HMAC-SHA256 Credential=XXXXXXXXXXXXXXXXXXX/20200401/us-east-1/appsync/aws4_request, SignedHeaders=accept;content-encoding;content-type;host;x-amz-date;x-amz-security-token, Signature=83EXAMPLEbcc1fe3ee69f75cd5ebbf4cb4f150e4f99cec869f149c5EXAMPLEdc" }

承載內容

{}

請求 URL

wss://api.example.com/graphql?header=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&payload=e30=
注意

一個 WebSocket 連線可以有多個訂閱 (即使使用不同的身分驗證模式)。其中一種實作方式是為第一個訂閱建立 WebSocket 連線,然後在最後一個訂閱取消註冊時將其關閉。您可以等待幾秒鐘再關閉 WebSocket 連線來最佳化此作業,以防應用程式在上次訂閱取消註冊後立即訂閱。對於行動應用程式範例,從一個畫面變更為另一個畫面、在卸載事件時停止訂閱,以及在載事件時啟動不同的訂閱。

Lambda 授權

標頭內容

  • "Authorization": <string>:傳遞為 的值authorizationToken

  • "host": <string>: AWS AppSync GraphQL 端點的主機或您的自訂網域名稱。

範例

{ "Authorization":"M0UzQzM1MkQtMkI0Ni00OTZCLUI1NkQtMUM0MTQ0QjVBRTczCkI1REEzRTIxLTk5NzItNDJENi1BQjMwLTFCNjRFNzQ2NzlCNQo=", "host":"example1234567890000.appsync-api.us-east-1.amazonaws.com" }

承載內容

{}

請求 URL

wss://example1234567890000.appsync-realtime-api.us-east-1.amazonaws.com/graphql?header=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&payload=e30=

即時 WebSocket 操作

使用 AWS AppSync 啟動成功的 WebSocket 交握後,用戶端必須傳送後續訊息,以連線至不同操作的 AWS AppSync。這些訊息需要下列資料:

  • type:操作類型。

  • id:訂閱的唯一識別符。我們建議您使用 UUID 來達到此目的。

  • payload:相關聯的承載,取決於操作類型。

type 欄位是唯一必要欄位; idpayload 欄位為選用。

事件順序

若要成功啟動、建立、註冊和處理訂閱請求,用戶端必須逐步執行下列順序:

  1. 初始化連線 (connection_init)

  2. 連線確認 (connection_ack)

  3. 訂閱註冊 (start)

  4. 訂閱確認 (start_ack)

  5. 正在處理訂閱 (data)

  6. 取消註冊訂閱 (stop)

連線初始化訊息

成功交握後,用戶端必須傳送訊息connection_init,以開始與 AWS AppSync 即時端點通訊。如果沒有此步驟,則會忽略所有其他訊息。該訊息是透過字串化以下 JSON 對象獲得的字串,如下所示:

{ "type": "connection_init" }

連線確認訊息

傳送 connection_init 訊息後,用戶端必須等待 connection_ack 訊息。接收前傳送的所有訊息connection_ack都會遭到忽略。該訊息應該如下所示:

{ "type": "connection_ack", "payload": { // Time in milliseconds waiting for ka message before the client should terminate the WebSocket connection "connectionTimeoutMs": 300000 } }

保持啟用訊息

除了連線確認訊息之外,用戶端還會定期接收保持連線訊息。如果用戶端未在連線逾時期間內收到保持連線訊息,用戶端應關閉連線。 AWS AppSync 會持續傳送這些訊息和服務已註冊的訂閱,直到其自動關閉連線 (24 小時後)。保持連線訊息是活動訊號,不需要用戶端來確認它們。

{ "type": "ka" }

訂閱註冊訊息

用戶端收到connection_ack訊息後,用戶端可以將訂閱註冊訊息傳送至 AWS AppSync。此類型的訊息是字串化 JSON 物件,其中包含下列欄位:

  • "id": <string>:訂閱的 ID。此 ID 對於每個訂閱都必須是唯一的,否則伺服器會傳回錯誤,指出訂閱 ID 重複。

  • "type": "start":常數 <string> 參數。

  • "payload": <Object>:包含訂閱相關資訊的物件。

    • "data": <string>:包含 GraphQL 查詢和變數的字串化 JSON 物件。

      • "query": <string>:GraphQL 操作。

      • "variables": <Object>:包含查詢變數的物件。

    • "extensions": <Object>:包含授權物件的物件。

  • "authorization": <Object>:包含授權所需欄位的物件。

訂閱註冊的授權物件

以 AWS AppSync API 授權模式為基礎的標頭參數格式 區段中的相同規則適用於授權物件。唯一的例外是 IAM,其中 SigV4 簽章資訊略有不同。如需詳細資訊,請參閱 IAM 範例。

使用 Amazon Cognito 使用者集區的範例:

{ "id": "ee849ef0-cf23-4cb8-9fcb-152ae4fd1e69", "payload": { "data": "{\"query\":\"subscription onCreateMessage {\\n onCreateMessage {\\n __typename\\n message\\n }\\n }\",\"variables\":{}}", "extensions": { "authorization": { "Authorization": "eyEXAMPLEiJjbG5xb3A5eW5MK09QYXIrMTJEXAMPLEBieU5WNHhsQjhPVW9YMnM2WldvPSIsImFsZyI6IlEXAMPLEn0.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.CT-qTCtrYeboUJ4luRSTPXaNewNeEXAMPLE14C6sfg05tO0fOMpiUwj9k19gtNCCMqoSsjtQoUweFnH4JYa5EXAMPLEVxOyQEQ4G7jQrt5Ks6STn53vuseR3zRW9snWgwz7t3ZmQU-RWvW7yQU3sNQRLEXAMPLEcd0yufBiCYs3dfQxTTdvR1B6Wz6CD78lfNeKqfzzUn2beMoup2h6EXAMPLE4ow8cUPUPvG0DzRtHNMbWskjPanu7OuoZ8iFO_Eot9kTtAlVKYoNbWkZhkD8dxutyoU4RSH5JoLAnrGF5c8iKgv0B2dfEXAMPLEIihxaZVJ9w9w48S4EXAMPLEcA", "host": "example1234567890000.appsync-api.us-east-1.amazonaws.com" } } }, "type": "start" }

使用 IAM 的範例:

{ "id": "eEXAMPLE-cf23-1234-5678-152EXAMPLE69", "payload": { "data": "{\"query\":\"subscription onCreateMessage {\\n onCreateMessage {\\n __typename\\n message\\n }\\n }\",\"variables\":{}}", "extensions": { "authorization": { "accept": "application/json, text/javascript", "content-type": "application/json; charset=UTF-8", "X-Amz-Security-Token": "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", "Authorization": "AWS4-HMAC-SHA256 Credential=XXXXXXXXXXXXXXXXXXXX/20200401/us-east-1/appsync/aws4_request, SignedHeaders=accept;content-encoding;content-type;host;x-amz-date;x-amz-security-token, Signature=b90131a61a7c4318e1c35ead5dbfdeb46339a7585bbdbeceeaff51f4022eb1fd", "content-encoding": "amz-1.0", "host": "example1234567890000.appsync-api.us-east-1.amazonaws.com", "x-amz-date": "20200401T001010Z" } } }, "type": "start" }

使用自訂網域名稱的範例:

{ "id": "key-cf23-4cb8-9fcb-152ae4fd1e69", "payload": { "data": "{\"query\":\"subscription onCreateMessage {\\n onCreateMessage {\\n __typename\\n message\\n }\\n }\",\"variables\":{}}", "extensions": { "authorization": { "x-api-key": "da2-12345678901234567890123456", "host": "api.example.com" } } }, "type": "start" }

SigV4 簽章不需要/connect附加至 URL,而 JSON 字串化 GraphQL 操作會取代 data。以下是 SigV4 簽章請求的範例:

{ url: "https://example1234567890000.appsync-api.us-east-1.amazonaws.com/graphql", data: "{\"query\":\"subscription onCreateMessage {\\n onCreateMessage {\\n __typename\\n message\\n }\\n }\",\"variables\":{}}", method: "POST", headers: { "accept": "application/json, text/javascript", "content-encoding": "amz-1.0", "content-type": "application/json; charset=UTF-8", } }

訂閱確認訊息

傳送訂閱開始訊息後,用戶端應等待 AWS AppSync 傳送訊息start_ackstart_ack 訊息指出訂閱成功。

訂閱確認範例:

{ "type": "start_ack", "id": "eEXAMPLE-cf23-1234-5678-152EXAMPLE69" }

錯誤訊息

如果連線初始化或訂閱註冊失敗,或訂閱從伺服器結束,伺服器會傳送錯誤訊息給用戶端:

  • "type": "error":常數 <string> 參數。

  • "id": <string>:對應已註冊訂閱的 ID,如果相關的話。

  • "payload" <Object>:包含對應錯誤資訊的物件。

範例:

{ "type": "error", "payload": { "errors": [ { "errorType": "LimitExceededError", "message": "Rate limit exceeded" } ] } }

處理資料訊息

當用戶端提交變動時, AWS AppSync 會識別對其感興趣的所有訂閱者,並使用id訂閱操作中對應的訂閱來傳送訊息"type":"data"給每個"start"訂閱者。用戶端應追蹤id其傳送的訂閱,以便在收到資料訊息時,用戶端可以將其與對應的訂閱配對。

  • "type": "data":常數 <string> 參數。

  • "id": <string>:對應已註冊訂閱的 ID。

  • "payload" <Object>:包含訂閱資訊的物件。

範例:

{ "type": "data", "id": "ee849ef0-cf23-4cb8-9fcb-152ae4fd1e69", "payload": { "data": { "onCreateMessage": { "__typename": "Message", "message": "test" } } } }

訂閱取消註冊訊息

當應用程式想要停止監聽訂閱事件時,用戶端應傳送具有下列字串化 JSON 物件的訊息:

  • "type": "stop":常數 <string> 參數。

  • "id": <string>:要取消註冊的訂閱 ID。

範例:

{ "type":"stop", "id":"ee849ef0-cf23-4cb8-9fcb-152ae4fd1e69" }

AWS AppSync 會傳送包含下列字串化 JSON 物件的確認訊息:

  • "type": "complete":常數 <string> 參數。

  • "id": <string>:未註冊訂閱的 ID。

用戶端收到確認訊息後,就不會再收到此特定訂閱的訊息。

範例:

{ "type":"complete", "id":"eEXAMPLE-cf23-1234-5678-152EXAMPLE69" }

斷開 WebSocket 的連線

在中斷連線之前,為了避免資料遺失,用戶端應具有必要的邏輯,以檢查目前沒有透過 WebSocket 連線進行的操作。從 WebSocket 中斷連線之前,所有訂閱都應該取消註冊。