构建实时终端节点 WebSocket 客户 - Amazon AppSync
实时 WebSocket GraphQL 订阅的客户端实现建立 Dews Device WebSocket 连接基于 Amazon AppSync API 授权模式的标头参数格式实时 WebSocket手术连接启动消息连接确认消息保持活动消息订阅注册消息订阅确认消息错误消息处理数据消息订阅取消注册消息断开 WebSocket
Amazon Web Services 文档中描述的 Amazon Web Services 服务或功能可能因区域而异。要查看适用于中国区域的差异，请参阅中国的 Amazon Web Services 服务入门。

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

构建实时终端节点 WebSocket 客户

实时 WebSocket GraphQL 订阅的客户端实现

以下顺序图和步骤显示了两者之间的实时订阅工作流 WebSocket 客户端、HTTP 客户端和Amazon AppSync.

  1. 客户建立了 WebSocket 与Amazon AppSync 实时终端节点。如果存在网络错误，则客户端应该执行抖动指数退避。有关更多信息，请参阅指数回退和抖动在Amazon建筑博客。

  2. 成功建立后 WebSocket 连接，客户端发送connection_init消息。

  3. 客户端等待connection_ack消息来自的消息Amazon AppSync. 此消息包括connectionTimeoutMs参数，这是以毫秒为单位的最长等待时间"ka"（保持连接）消息。

  4. Amazon AppSync 发送"ka"定期发送消息。客户端跟踪收到的时间"ka"消息。如果客户没有收到"ka"内部消息connectionTimeoutMs毫秒，客户端应关闭连接。

  5. 客户端通过发送 start 订阅消息来注册订阅。单个单个数 WebSocket 连接支持多个订阅，即使它们处于不同的授权模式。

  6. 客户端等待 Amazon AppSync 发送 start_ack 消息来确认订阅成功。如果出现错误，则 Amazon AppSync 返回一条 "type": "error" 消息。

  7. 客户端监听订阅事件，这些事件是在调用对应的更改之后发送的。查询和更改通常通过 https:// 发送到 Amazon AppSync GraphQL 终端节点。订阅流经过Amazon AppSync 使用安全的实时终端节点 WebSocket (wss://)。

  8. 客户端通过发送 stop 订阅消息来取消注册订阅。

  9. 取消注册所有订阅并检查没有通过 WebSocket，客户端可以断开与 WebSocket 连接.

建立 Dews Device WebSocket 连接

使用进行连接并启动成功的握手Amazon AppSync，一个 WebSocket 客户端需要以下内容：

  • 这些区域有：Amazon AppSync 实时终端节点

  • 查询字符串，了解相关信息header和payload参数

    • header：包含与 Amazon AppSync 终端节点和授权相关的信息。这是一个来自字符串化 JSON 对象的 base64 编码字符串。JSON 对象内容因授权模式而异。

    • payload：Base64 编码的字符串payload.

有了这些要求， WebSocket 客户端可以使用以下方式连接到 URL，该 URL 包含带有查询字符串的实时终端节点graphql-ws作为 WebSocket 协议。

从 GraphQL 终端节点发现 实时终端节点

Amazon AppSync GraphQL 终端节点和 Amazon AppSync 实时终端节点在协议和域方面略有不同。您可以使用检索 GraphQL 终端节点的Amazon Command Line Interface(Amazon CLI) 命令aws appsync get-graphql-api.

Amazon AppSync GraphQL 终端节点：

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

Amazon AppSync 实时终端节点：

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

应用程序可以使用任何 HTTP 客户端连接到 Amazon AppSync GraphQL 终端节点 (https://) 进行查询和更改。应用程序可以连接到Amazon AppSync 实时终端节点 (wss://) 使用任何 WebSocket 订阅客户端。

使用自定义域名，您可以使用单个域与两个端点进行交互。例如，如果您配置api.example.com作为您的自定义域，您可以使用以下 URL 与 GraphQL 和实时端点进行交互：

Amazon AppSync 自定义域 GraphQL 终端节点：

https://api.example.com/graphql

Amazon AppSync 自定义域实时终端节点：

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

基于 Amazon AppSync API 授权模式的标头参数格式

的格式header连接查询字符串中使用的对象因Amazon AppSync API 授权模式。对象中的 host 字段引用 Amazon AppSync GraphQL 终端节点，该终端节点用于验证连接，即使 wss:// 调用针对的是实时终端节点。要启动握手并建立授权连接，payload 应为空 JSON 对象。

API 密钥

标头内容：

  • "host": <string>: 的主机Amazon AppSync GraphQL 终端节点或您的自定义域名。

  • "x-api-key": <string>：为配置的 API 密钥Amazon AppSync API。

示例：

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

负载内容：

{}

请求 URL：

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

Amazon Cognito 用户池和 OpenID Connect (OIDC)

标头内容：

  • "Authorization": <string>: 一个 JWT ID 令牌。标题可以使用持票人计划.

  • "host": <string>: 的主机Amazon AppSync GraphQL 终端节点或您的自定义域名。

示例：

{
    "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"
}

负载内容：

{}

请求 URL：

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

IAM

标头内容如下：

  • "accept": "application/json, text/javascript"：常量 <string> 参数。

  • "content-encoding": "amz-1.0"：常量 <string> 参数。

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

  • "host": <string>：这是 Amazon AppSync GraphQL 终端节点的主机。-"x-amz-date": <string>：时间戳必须采用 UTC 表示，并具有以下 ISO 8601 格式：YYYMMDD'T'HHMMSS'Z'。例如，20150830T123600Z 是一个有效的时间戳。请勿在时间戳中包含毫秒。有关更多信息，请参阅处理 Signature Version 4 中的日期中的Amazon一般参考.

    • "X-Amz-Security-Token":<string>: 这些区域有：Amazon会话令牌，使用临时安全证书时必需。有关更多信息，请参阅将临时凭证用于Amazon资源中的IAM 用户指南.

    • "Authorization": <string>：签名版本 4 (SigV4) 签名信息Amazon AppSync 终端节点。有关签名过程的更多信息，请参阅。任务 4 将签名添加到 HTTP 请求中的Amazon一般参考.

Sigv4 签名 HTTP 请求包含一个规范 URL，它是附加了 /connect 的 Amazon AppSync GraphQL 终端节点。服务终端节点Amazon区域与您正在使用的区域相同Amazon AppSync API，服务名称为 “appsync”。要签名的 HTTP 请求如下所示：

{
  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",
  }
}

示例：

{
  "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"
}

负载内容：

{}

请求 URL：

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

要使用自定义域签署请求，请执行以下操作：

{
  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",
  }
}

示例：

{
  "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": "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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"
}

负载内容：

{}

请求 URL：

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

注意：第一 WebSocket 连接可以有多个订阅（即使使用不同的身份验证模式）。实现此目的的一种方法是创建一个 WebSocket 连接第一个订阅，然后在取消注册最后一个订阅时关闭它。您可以通过等待几秒钟再关闭来优化此功能 WebSocket 连接，以避免在取消注册最后一个订阅之后立即订阅应用程序。对于移动应用程序示例，在从一个屏幕更改到另一个屏幕时，打开卸载event 它会停止订阅，然后开启安装中如果它启动了不同的订阅。

Lambda 授权

标头内容：

  • "Authorization": <string>: 传递的值为authorizationToken.

  • "host": <string>: 的主机Amazon AppSync GraphQL 终端节点或您的自定义域名。

示例：

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

负载内容：

{}

请求 URL：

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

实时 WebSocket手术

成功启动后 WebSocket 与握手Amazon AppSync，客户端必须发送后续消息才能连接到Amazon AppSync 用于不同的操作。这些消息需要以下数据：

  • type：操作的类型。

  • id：订阅的唯一标识符。我们建议为此目的使用 UUID。

  • payload：关联的有效载荷，取决于操作类型。

这些区域有：type字段是唯一的必填字段；id和payload字段是可选的。

事件序列

要成功启动、建立、注册和处理订阅请求，客户端必须逐步完成以下序列：

  1. 初始化连接 (connection_init)

  2. 连接确认 (connection_ack)

  3. 订阅注册 (start)

  4. 订阅确认 (start_ack)

  5. 处理订阅 (data)

  6. 订阅取消注册 (stop)

连接启动消息

成功握手后，客户端必须发送connection_init要开始与通信的消息Amazon AppSync实时终端节点。如果没有此步骤，将忽略所有其他消息。该消息是通过将下列 JSON 对象字符串化获得的字符串，如下所示：

{ "type": "connection_init" }

连接确认消息

发送 connection_init 消息后，客户端必须等待 connection_ack 消息。接收前发送的所有消息connection_ack被忽略。该消息具体如下：

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

保持活动消息

除了连接确认消息外，客户端还会定期接收保持活动消息。如果客户端在连接超时时间内没有收到保持活动状态的消息，则客户端应关闭连接。Amazon AppSync 继续发送这些消息并为注册的订阅提供服务，直到连接自动关闭（24 小时后）。保持活动状态消息是检测信号，不需要客户端确认。

{ "type": "ka" }

订阅注册消息

客户端收到后connection_ack消息，客户端可以将订阅注册消息发送到Amazon AppSync. 此类型的消息是包含以下字段的字符串化 JSON 对象：

  • "id": <string>：订阅的 ID。此对于每个订阅都必须唯一，否则服务器将返回一个错误，指示订阅ID重复。

  • "type": "start"：常量 <string> 参数。

  • "payload": <Object>：包含与订阅相关的信息的对象。

    • "data": <string>：包含 GraphQL 查询和变量的字符串化 JSON 对象。

      • "query": <string>：GraphQL 操作。

      • "variables": <Object>：包含查询变量的对象。

    • "extensions": <Object>：包含授权对象的对象。

  • "authorization": <Object>：包含授权所需字段的对象。

订阅注册的授权对象

在基于 Amazon AppSync API 授权模式的标头参数格式部分中的相同规则适用于授权对象。唯一的例外是 IAM，此时 Sigv4 签名信息略有不同。有关详细信息，请参阅 IAM 示例。

使用 Amazon Cognito 用户池的示例：

{
  "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 的示例：

{
  "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"
}

使用自定义域名的示例：

{
  "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 签名不需要/connect将附加到 URL，并使用 JSON 字符串化 GraphQL 操作替换data. 以下是 Sigv4 签名请求的示例：

{
  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",
  }
}

订阅确认消息

发送订阅开始消息后，客户端应等待Amazon AppSync发送了start_ack消息。这些区域有：start_ack消息会表明订阅成功。

订阅确认示例：

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

错误消息

如果连接启动或订阅注册失败，或者从服务器终止订阅，服务器将向客户端发送错误消息：

  • "type": "error"：常量 <string> 参数。

  • "id": <string>：对应已注册订阅的 ID（如果相关）。

  • "payload" <Object>：包含对应错误信息的对象。

示例：

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

处理数据消息

当客户提交突变时，Amazon AppSync 识别所有对此感兴趣的订阅者并发送"type":"data"使用相应的订阅向每个人发送消息id来自 的"start"订阅操作。客户需要跟踪订阅id它发送的这样在收到数据消息时，客户端可以将其与对应的订阅匹配。

  • "type": "data"：常量 <string> 参数。

  • "id": <string>：对应已注册订阅的 ID。

  • "payload" <Object>：包含订阅信息的对象。

示例：

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

订阅取消注册消息

当应用程序希望停止侦听订阅事件时，客户端应发送带有以下字符串化 JSON 对象的消息：

  • "type": "stop"：常量 <string> 参数。

  • "id": <string>：要取消注册的订阅的 ID。

示例：

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

Amazon AppSync 使用以下字符串化 JSON 对象发回确认消息：

  • "type": "complete"：常量 <string> 参数。

  • "id": <string>：取消注册的订阅的 ID。

客户端收到确认消息后，它将不再收到有关此特定订阅的消息。

示例：

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

断开 WebSocket

在断开连接之前，为避免数据丢失，客户端应具有必要的逻辑，检查当前没有执行任何操作 WebSocket连接. 在断开连接之前，应先取消注册所有订阅 WebSocket.