I want to connect a 'real device' with Azure IoT Central and connect a local source application to it using MQTT. I use this code for the connection and replace.
However, I cannot find any information on how to provide the timestamp. This thread suggests to set "iothub-creation-time-utc" as a "property" - I am not sure how to do that however. Is there any documentation on this?
add the property to the message:
message.properties.add('iothub-creation-time-utc', utcDT);
Based on the links in your question I assume you are using Node.js to develop your device code. There is a sample code snippet that shows how to set the creation time property here:
https://learn.microsoft.com/en-us/azure/iot-accelerators/iot-accelerators-connecting-pi-node
function sendTelemetry(data, schema) {
if (deviceOnline) {
var d = new Date();
var payload = JSON.stringify(data);
var message = new Message(payload);
message.properties.add('iothub-creation-time-utc', d.toISOString());
message.properties.add('iothub-message-schema', schema);
console.log('Sending device message data:\n' + payload);
client.sendEvent(message, printErrorFor('send event'));
} else {
console.log('Offline, not sending telemetry');
}
}
Related
I am trying to listen to a follow event in this twitter bot but it doesn't work? Any idea?
Thank in advance
const stream = T.stream("statuses/filter", { track:"<twitteraccount>" });
function followed(event) {
console.log("follow event");
const name = event.source.name;
const screenName = event.source.screen_name;
tweeting(".#" + screenName + " hello you");
}
stream.on("follow", followed);
There is no follow event in the filtered stream API. Where are you seeing this documented? In order to build something like this, you would need to use webhooks, and the Account Activity API.
I am using Service Bus Explorer as a quick way of testing a rule that does not work when deployed via ARM.
In JavaScript in the Azure Function I am setting the Topic message to:
context.bindings.outputSbMsg = { Indicator: 'Itinerary'};
In Service Bus Explorer I am setting a Rule on a Subscription with this string:
Indicator = 'Itinerary'
But messages sent to the Topic do not go to this Subscription ( they go to another with the rule 1 = 1)
Question: What am I missing here?
Supplementary info:
I do not seem to have access to the Indicator property. As a test I created an action on the 1=1 rule that appended to the Indicator property and the result was empty.
I am able to access the Indicator property in JavaScript if I have a Function that is triggered by the 1 = 1 rule, so the property is there.
The rule doesn't work because
The rule works against system or user-defined properties rather than message body.
What js function outputs is merely message body, i.e. context.bindings.outputSbMsg = { Indicator: 'Itinerary'}; sends a message { Indicator: 'Itinerary'} and no property is set by us.
And the default rule with 1=1 true filter enables all messages to be selected into the subscription, so you see messages went there all the time. Check doc of topic filters for more details.
For now, it's by design that js function output can't populate message properties. To make the filter work, we have to send messages with property using SDK instead. Install azure-sb package then try sample code below.
const azuresb = require("azure-sb");
const connStr = "ServiceBusConnectionString";
const mytopic = "mytopic";
var serviceBus = azuresb.createServiceBusService(connStr);
const msg =
{
body: "Testing",
customProperties: {
Indicator: 'Itinerary'
}
};
serviceBus.sendTopicMessage(mytopic, msg, function(error) {
if (error) {
context.log(error);
}
else{
context.log("Message Sent");
}
});
I am fairly new to React Native, but I created a simple app that has a button and a text that changes when the button is clicked. However, I want to connect to the IoT hub and receive information from the hub.
I am having issues currently with the connection. Here is my code:
import React from 'react';
import {StyleSheet, Dimensions, Alert, Text, View, Image, Button} from 'react-native';
const { width, height } = Dimensions.get("window");
'use strict';
var iothub = require('azure-iothub');
var connectionString = 'connection string';
var Mqtt = require('azure-iot-device-mqtt').Mqtt;
var DeviceClient = require('azure-iot-device').Client
var Message = require('azure-iot-device').Message;
var client = DeviceClient.fromConnectionString(connectionString, Mqtt);
// Create a message and send it to the IoT hub every second
setInterval(function(){
// Simulate telemetry.
var temperature = 20 + (Math.random() * 15);
var message = new Message(JSON.stringify({
temperature: temperature,
humidity: 60 + (Math.random() * 20)
}));
// Add a custom application property to the message.
// An IoT hub can filter on these properties without access to the message body.
message.properties.add('temperatureAlert', (temperature > 30) ? 'true' : 'false');
console.log('Sending message: ' + message.getData());
// Send the message.
client.sendEvent(message, function (err) {
if (err) {
console.error('send error: ' + err.toString());
} else {
console.log('message sent');
}
});
}, 1000);
The above part is a Node.js code, but I want to use it in a React application. How do I use Node packages in React?
I am getting the following error: Could not connect to development server.
Thanks.
As in your other question, I would suggest you take a look at Azure IoT Starter Kit Companion, which is a sample React Native application that helps you get your IoT device connected to an IoT Hub on iOS, Android and Windows.
Hope it helps!
Small point, you should NOT publish your connection strings. This is a rather large security issue.
As mentioned in your other question, the Azure IoT Hub Device SDK needs a Node.js runtime, which does not exists within the React Native app.
There is a plugin called nodejs-mobile-react-native for React Native that brings in the Node.js runtime and enables you to run Node.js apps alongside your React Native application.
I have written a detailed blog post about this topic outlining the steps necessary to achieve this.
I am trying to make a chat system where only two users are able to talk to each other at a time ( much like facebook's chat )
I've tried multiplexing, using mongoDB's _id as the name so every channel is unique.
The problem I'm facing is that I cannot direct a message to a single client connection.
this is the client side code that first sends the message
$scope.sendMessage = function() {
specificChannel.send(message)
$scope.messageText = '';
};
this is the server side receiving the message
specificChannel.on('connection', function (conn) {
conn.on('data', function(message){
conn.write('message')
}
}
When I send a message, to any channel, every channel still receives the message.
How can I make it so that each client only listens to the messages sent to a specific channel?
It appeared that SockJS doesn't support "private" channels. I used the following solution for a similar issue:
var channel_id = 'my-very-private-channel'
var connection = new SockJS('/pubsub', '')
connection.onopen = function(){
connection.send({'method': 'set-channel', 'data': {'channel': channel_id}})
}
Backend solution is specific for every technology stack so I can't give a universal solution here. General idea is the following:
1) Parse the message in "on_message" function to find the requested "method name"
2) If the method is "set-channel" -> set the "self.channel" to this value
3) Broadcast further messages to subscribers with the same channel (I'm using Redis for that, but it also depends on your platform)
Hope it helps!
I’ve got a WinRT app that I’m using the Windows Azure Toolkit for Windows 8 with. I’ve got a setup where I’d like clients subscribed to ignore messages posted to a ServiceBus Topic if they’re the originator or if the message is older than when their subscription started.
In the Properties of my BrokeredMessage, I’ve added 2 items to cover these scenarios:
message.Properties["Timestamp"] = DateTime.UtcNow.ToFileTime();
message.Properties["OriginatorId"] = clientId.ToString();
clientId is a Guid.
The subscriber side looks like this:
// ti is a class that contains a Topic, Subscription and a bool as a cancel flag.
string FilterName = "NotMineNewOnly";
// Find or create the topic.
if (await Topic.ExistsAsync(DocumentId.ToString(), TokenProvider))
{
ti.Topic = await Topic.GetAsync(DocumentId.ToString(), TokenProvider);
}
else
{
ti.Topic = await Topic.CreateAsync(DocumentId.ToString(), TokenProvider);
}
// Find or create this client's subscription to the board.
if (await ti.Topic.Subscriptions.ExistsAsync(ClientSettings.Id.ToString()))
{
ti.Subscription = await ti.Topic.Subscriptions.GetAsync(ClientSettings.Id.ToString());
}
else
{
ti.Subscription = await ti.Topic.Subscriptions.AddAsync(ClientSettings.Id.ToString());
}
// Find or create the subscription filter.
if (!await ti.Subscription.Rules.ExistsAsync(FilterName))
{
// Want to ignore messages generated by this client and ignore any that are older than Timestamp.
await ti.Subscription.Rules.AddAsync(FilterName, sqlFilterExpression: string.Format("(OriginatorId != '{0}') AND (Timestamp > {1})", ClientSettings.Id, DateTime.UtcNow.ToFileTime()));
}
ti.CancelFlag = false;
Topics[boardId] = ti;
while (!ti.CancelFlag)
{
BrokeredMessage message = await ti.Subscription.ReceiveAndDeleteAsync(TimeSpan.FromSeconds(30));
if (!ti.CancelFlag && message != null)
{
// Everything gets here! :(
}
I get back everything – so I’m not sure what I’m doing wrong. What’s the easiest way to troubleshoot problems with subscription filters?
When you create a Subscription then by default you get a "MatchAll" filter. In the code above you are just adding your filter so it is applied in addition to the "MatchAll" filter and thus all messages are recieved. Just delete the $Default filter once the Subscription is created and that should resolve the issue.
Best way to troubleshoot is using the Service Bus Explorer from Paolo Salvatori
http://code.msdn.microsoft.com/windowsazure/Service-Bus-Explorer-f2abca5a
He has done a good few blog posts on it e.g. http://windowsazurecat.com/2011/07/exploring-topics-and-queues-by-building-a-service-bus-explorer-toolpart-1/
Windows Azure SDK 1.7 does have built in capability but the Service Bus Explorer Standalone version is still better, see comparison here.
http://soa-thoughts.blogspot.com.au/2012/06/visual-studio-service-bus-explorer.html
HTH your debugging...