Question

我有一个Web API，可以接收和发送消息到Raspberry Pi。使用web API上的azure-event-hubs接收消息，使用azure-iothub将消息发送到raspberry，连接正常。

我遇到的问题是当我尝试在onMessage函数中发送消息时（因此每当我在webapi中收到消息时），设备都不会收到它。这是我的代码：

的WebAPI：

const { EventHubClient, EventPosition } = require('azure-event-hubs');
var connectionString = 'myConnectionString'
var sendingClient = require('../azure/sendingClient')

async function main() {
    sendingClient.sendMessage('raspberry',{},"allDevices")  //The raspberry receives this  
    const client = await 
    EventHubClient.createFromIotHubConnectionString(connectionString);

    const onError = (err) => {
        console.log("An error occurred on the receiver ", err);
    };

    const onMessage = (msg) => {
        console.log(msg.body);
        sendingClient.sendMessage('raspberry',{},"allDevices")// the raspberry doesn't receive this
    };

    const receiveHandler = client.receive("1", onMessage, onError, { 
        eventPosition: EventPosition.fromEnqueuedTime(Date.now()) 
    });

  // To stop receiving events later on...
  await receiveHandler.stop();
  await client.close();
}

main().catch((err) => {
    console.log(err);
});

发送客户：

var Client = require('azure-iothub').Client;
var Message = require('azure-iot-common').Message;

var connectionString = 'myConnectionString'

var sendingClient = Client.fromConnectionString(connectionString);

exports.sendMessage = (targetDevice, content, messageId) => {
    sendingClient.open(function (err) {
        if (err) {
            console.error('Could not connect: ' + err.message);
        } else {
            console.log('Service client connected');
            var message = new Message(content);
            message.ack = 'full';
            message.messageId = 'message'
            message.properties.add('message',messageId)
            console.log('Sending message: ' + message.getData());
            console.log('Sending message to : ' + targetDevice);            
            sendingClient.send(targetDevice, message,);
        }
    });
}

raspberryPi上的接收者：

var iothub = require('azure-iothub');
var Protocol = require('azure-iot-device-mqtt').Mqtt;
var Client = require('azure-iot-device').Client;
var Message = require('azure-iot-device').Message;
var client = Client.fromConnectionString(connectionString, Protocol)
client.open((err) => {
    if (err) console.error('Could not connect: ' + err.message)
    else {
        client.on('message', (msg) => {
            switch (msg.properties.propertyList[1].value) {
                case 'allDevices':
                    devices = JSON.parse(msg.data.toString())
                    response(devices) //passing the message content
            }
        });

        client.on('error', (err) => {
            console.error(err.message);
        });

        client.on('disconnect', () => {
            clearInterval(sendInterval);
            client.removeAllListeners();
            client.open(connectCallback);
        });
    }
})

RaspberryPi上的发件人：

exports.sendMessage = (data, connectionString, key) => {
    var client = Client.fromConnectionString(connectionString, Protocol)
    client.open((err) => {
        if (err) console.error('Send message error: ' + err.message)
        else {
            data = JSON.stringify(data);
            var message = new Message(data);
            message.properties.add('message', key);
            client.sendEvent(message);
            console.log('Message sent ' + key);
        }
    })
}

Answer 1

我认为这是由于事件中心客户端无法接收来自分区＆＃34; 1＆＃34;的消息。无法向IoT Hub中的特定分区发送消息，内部使用分区以允许扩展IoT（事件中心）并允许扩展消费者应用程序。您可以尝试使用以下代码来接收来自所有分区的消息。

  const partitionIds = await client.getPartitionIds();
  partitionIds.forEach(function(id,index){
    const receiveHandler = client.receive(id, onMessage, onError, { eventPosition: EventPosition.fromEnqueuedTime(Date.now()) });  
  });

<强>更新

<强> WebApi.js

const { EventHubClient, EventPosition } = require('azure-event-hubs');
var connectionString = '{iot-hub-connectionstring}';
var sendingClient = require('./sendingClient');

async function main() {
    sendingClient.sendMessage('raspberry',{},"raspberry-first")  //The raspberry receives this  
    const client = await EventHubClient.createFromIotHubConnectionString(connectionString);

    const onError = (err) => {
        console.log("An error occurred on the receiver ", err);
    };

    const onMessage = (msg) => {
        console.log("receive response");
        console.log(msg.body);
        sendingClient.sendMessage('raspberry',{},"raspberry-second")// the raspberry doesn't receive this
    };

    const partitionIds = await client.getPartitionIds();
    partitionIds.forEach(function(id,index){
        const receiveHandler = client.receive(id, onMessage, onError, { eventPosition: EventPosition.fromEnqueuedTime(Date.now()) });  
    });  
}

main().catch((err) => {
    console.log(err);
});

<强> sendingClient.js

var Client = require('azure-iothub').Client;
var Message = require('azure-iot-common').Message;

var connectionString = '{iot-hub-connectionstring}';

var sendingClient = Client.fromConnectionString(connectionString);

exports.sendMessage = (targetDevice, content, messageId) => {
    sendingClient.open(function (err) {
        if (err) {
            console.error('Could not connect: ' + err.message);
        } else {
            console.log('Service client connected');
            var message = new Message(content);
            message.ack = 'full';
            message.messageId = 'message'
            message.properties.add('message',messageId)
            console.log('Sending message: ' + message.getData());
            console.log('Sending message to : ' + targetDevice);            
            sendingClient.send(targetDevice, message,);
        }
    });
}

<强> Receiver.js var Protocol = require（＆＃39; azure-iot-device-mqtt＆＃39;）。Mqtt; var Client = require（＆＃39; azure-iot-device＆＃39;）。客户; var Message = require（＆＃39; azure-iot-device＆＃39;）。消息;

var connectionString = "{iot-hub-device-connectionstring}";

// fromConnectionString must specify a transport constructor, coming from any transport package.
var client = Client.fromConnectionString(connectionString, Protocol);

var connectCallback = function (err) {
  if (err) {
    console.error('Could not connect: ' + err.message);
  } else {

    console.log('Client connected');
    client.on('message', function (msg) {

        // When using MQTT the following line is a no-op.
        client.complete(msg, printResultFor('completed'));
        console.log(msg.properties.propertyList[1].value);              
    });

    client.on('error', function (err) {
      console.error(err.message);
    });

    client.on('disconnect', function () {
      client.removeAllListeners();
      client.open(connectCallback);
    });
  }
};

client.open(connectCallback);

// Helper function to print results in the console
function printResultFor(op) {
  return function printResult(err, res) {
    if (err) console.log(op + ' error: ' + err.toString());
    if (res) console.log(op + ' status: ' + res.constructor.name);
  };
}

测试结果

BTW，我已将所有azure- *库更新为最新版本。

不接收从azure-event-hubs onMessage函数

1 个答案: