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适用于 Express 的 Azure Web PubSub CloudEvents 处理程序

Azure Web PubSub 服务 是一种 Azure 托管服务,可帮助开发人员轻松构建具有实时功能和发布-订阅模式的 Web 应用程序。 任何需要在服务器和客户端或客户端之间进行实时发布-订阅消息传送的方案都可以使用 Azure Web PubSub 服务。 通常需要从服务器轮询或提交 HTTP 请求的传统实时功能也可以使用 Azure Web PubSub 服务。

当 WebSocket 连接连接时,Web PubSub 服务会将连接生命周期和消息转换为 CloudEvents 格式的事件。 此库提供一个快速中间件来处理表示 WebSocket 连接的生命周期和消息的事件,如下图所示:

云事件

关于这里使用的术语的详细信息,详见 关键概念 部分。

源代码 | 包 (NPM) | API 参考文档 | 产品文档 | 样品

入门

目前支持的环境

先决条件

1.安装 @azure/web-pubsub-express

npm install @azure/web-pubsub-express

2. 创建 WebPubSubEventHandler

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat");

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

重要概念

连接

连接,也称为客户端或客户端连接,表示连接到Web PubSub服务的单个WebSocket连接。 成功连接后,Web PubSub服务会为该连接分配一个唯一的连接ID。

Hub

中心是一组客户端连接的逻辑概念。 通常你用一个枢纽来做一个目的,比如聊天中心或通知中心。 创建客户端连接时,它会连接到中心,并在其生存期内,它属于该中心。 不同的应用程序可以使用不同的中心名称共享一个 Azure Web PubSub 服务。

组是与中心的连接子集。 可以随时向组添加客户端连接或者从组中删除客户端连接。 例如,当某个客户端加入聊天室,或某个客户端离开聊天室,此类聊天室可以看成是一个组。 一个客户端可以加入多个组,一个组可以包含多个客户端。

User

与 Web PubSub 的连接可以属于一个用户。 用户可能具有多个连接,例如当单个用户跨多个设备或多个浏览器选项卡进行连接时。

客户端事件

事件是在客户端连接生命周期内创建的。 例如,一个简单的WebSocket客户端连接在尝试连接服务时会触发 connect 事件,成功连接服务时触发 connected 事件,发送消息给服务时触发 message 事件,断开连接时触发 disconnected 事件。

事件处理程序

事件处理程序包含处理客户端事件的逻辑。 事件处理程序需要先通过门户或 Azure CLI 注册并配置。 托管事件处理逻辑的地方通常被视为服务器端。

示例

处理connect请求并分配<userId>

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  handleConnect: (req, res) => {
    // auth the connection and set the userId of the connection
    res.success({
      userId: "<userId>",
    });
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 connect 请求,如果认证失败就拒绝连接

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  handleConnect: (req, res) => {
    // auth the connection and reject the connection if auth failed
    res.fail(401, "Unauthorized");
    // the following method is also a valid approach
    // res.failWith({ code: 401, detail: "Unauthorized" });
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 connected 请求

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  onConnected: (connectedRequest) => {
    // Your onConnected logic goes here
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 onGroupJoined 请求

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  onGroupJoined: (groupJoinedRequest) => {
    console.log(
      `Connection ${groupJoinedRequest.context.connectionId} joined group ${groupJoinedRequest.group}`,
    );
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 onGroupLeft 请求

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  onGroupLeft: (groupLeftRequest) => {
    console.log(
      `Connection ${groupLeftRequest.context.connectionId} left group ${groupLeftRequest.group}`,
    );
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 onDisconnected 请求

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  onDisconnected: (disconnectedRequest) => {
    // Your onDisconnected logic goes here
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 connect mqtt 请求,并 <userId> 分配 和 <mqtt> 属性

import { WebPubSubEventHandler, MqttConnectRequest } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  handleConnect: (req, res) => {
    if (req.context.clientProtocol === "mqtt") {
      // return mqtt response when request is of MQTT kind
      // get connect request as mqtt request and print it
      const mqttRequest = req as MqttConnectRequest;
      console.log(mqttRequest);

      // auth the connection and return mqtt response
      res.success({
        userId: "user1",
        mqtt: { userProperties: [{ name: "a", value: "b" }] },
      });
    } else {
      res.success({
        userId: "user1",
      });
    }
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 connect mqtt请求,如果认证失败则拒绝连接

import { WebPubSubEventHandler, MqttConnectRequest } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  handleConnect: (req, res) => {
    // auth the connection and reject the connection if auth failed
    if (req.context.clientProtocol === "mqtt") {
      // return mqtt error response when request is of MQTT kind
      // get connect request as mqtt request and print it
      const mqttRequest = req as MqttConnectRequest;
      console.log(mqttRequest);

      // auth the connection and return mqtt failure response
      res.fail(401, "Not Authorized");

      // Or use below method for more fine-grained control over the MQTT return code
      // res.failWith({ mqtt: { code: MqttV500ConnectReasonCode.NotAuthorized } });
    } else res.success();
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

处理 onDisconnected for mqtt 请求

import { WebPubSubEventHandler, MqttDisconnectedRequest } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  onDisconnected: (disconnectedRequest) => {
    if (disconnectedRequest.context.clientProtocol === "mqtt") {
      // get disconnect request as mqtt request and print it
      const mqttRequest = disconnectedRequest as MqttDisconnectedRequest;
      console.log(mqttRequest.mqtt);
      // Your onDisconnected logic goes here
    } else {
      console.log(disconnectedRequest);
      // Your onDisconnected logic goes here
    }
  },
  allowedEndpoints: ["https://<yourAllowedService>.webpubsub.azure.com"],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

仅允许指定的终结点

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  allowedEndpoints: [
    "https://<yourAllowedService1>.webpubsub.azure.com",
    "https://<yourAllowedService2>.webpubsub.azure.com",
  ],
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

设置自定义事件处理程序路径

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  path: "/customPath1",
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  // Azure WebPubSub Upstream ready at http://localhost:3000/customPath1
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

设置和读取连接状态

import { WebPubSubEventHandler } from "@azure/web-pubsub-express";
import express from "express";

const handler = new WebPubSubEventHandler("chat", {
  handleConnect(req, res) {
    // You can set the state for the connection, it lasts throughout the lifetime of the connection
    res.setState("calledTime", 1);
    res.success();
  },
  handleUserEvent(req, res) {
    const calledTime = req.context.states.calledTime++;
    console.log(calledTime);
    // You can also set the state here
    res.setState("calledTime", calledTime);
    res.success();
  },
});

const app = express();

app.use(handler.getMiddleware());

app.listen(3000, () =>
  console.log(`Azure WebPubSub Upstream ready at http://localhost:3000${handler.path}`),
);

Troubleshooting

启用日志

启用日志记录可能有助于发现有关故障的有用信息。 若要查看 HTTP 请求和响应的日志,请将 AZURE_LOG_LEVEL 环境变量设置为 info

export AZURE_LOG_LEVEL=verbose

或者,也可以通过在setLogLevel中调用@azure/logger来启用日志:

import { setLogLevel } from "@azure/logger";

setLogLevel("info");

有关如何启用日志的更详细说明,可以查看 @azure/记录器包文档

实时跟踪

使用 Web PubSub 服务门户中的 实时跟踪 查看实时流量。

后续步骤

请查看 samples 目录,了解如何使用该库的详细示例。

Contributing

若要参与此库,请阅读 贡献指南 了解有关如何生成和测试代码的详细信息。