If there 4 clients that publish audio stream to a topic and are also subscribed to it, is it possible to restrict publishing for other clients when one client is publishing. More like a push-to-talk service.
Related
I set up an architect for my solution think that iot hub does the work of an mqtt broker, but when I started the implementation , I found that you cannot subscribe to a specific subject to retrieve messages published by another mqtt client, the notion of topic does not exist on iot hub.
I have read several articles about this subject but I have not found an appropriate alternative.
Iot hub has only two topics, and event hub endpoints are limited to 10 endpoints
Can you guide me or suggest a solution with a broker?
How can I subscribe to a specific topic?
I want a device to device communication with pub / sub
Example: a device publishes on a topic / home / room
another device subscribes to / home / room
using iot hub
I am open to all proposals
Thank you
Cloud development
IoT Hub has a limited MQTT broker implementation, because of that, you can't subscribe to device topics from other devices. You could use an Azure Function to catch all your messages and decide if it needs to send a Cloud to Device message. You could also leverage Stream Analytics to decide if a message needs to be sent before talking to that Function. This is probably your best bet if you want to play by Azure IoT Stack's rules.
No cloud development
If you really want your devices to listen to each other, there is an old blog post that describes a scenario where a device uses the service SDK to listen to messages sent to IoT Hub by a different device. It lists the pros and cons in the post.
Custom edge module
If your devices are on the same network, you could build an Edge Module that implements an MQTT broker. The devices would then connect to the edge device as they would in a normal gateway scenario, but also to your custom broker. In your routing, you would then send all the messages to your custom broker to be transmitted to any devices listening to that topic, while still sending the data to the cloud. I imagine their are a few security risks you want to look into if you go in this direction.
So in short: it's possible, probably in many other ways, but in the end you are leveraging a cloud platform that doesn't support this natively.
Goal: Send messages to a group of Azure IoT Hub Devices that are connected via MQTT WebSocket.
Initial Idea: Have a group of IoT Hub Devices (group X) subscribe to messages with topic X.
Problem:
On the Communicate with your IoT hub using the MQTT protocol docs, I don't see a way to subscribe a device to additional topics. I only see examples of a subscription to a device specific endpoint devices/{device_id}/messages/devicebound/#.
The page goes on to say "IoT Hub is not a general purpose pub-sub messaging broker, it only supports the documented topic names and topic filters." I think those topics are
devices/{device_id}/messages/devicebound/
devices/{device_id}/messages/devicebound/#
My Conclusion: I can't have a group of IoT Hub Devices (group X) subscribe to messages with topic X.
Questions:
Is my conclusion correct?
If my conclusion is correct, is there another way I can send messages to a group of Azure IoT Hub Devices that are connected via MQTT WebSocket?
Your conclusion is correct. Azure IoT Hub is not an MQTT broker per se.
If you want to send messages to a group of devices connected to Azure IoT Hub (independently of the protocol they are connected with), you need to look into one of the Cloud 2 Device features of IoT Hub.
Depending on your scenario you can use one of the following: Cloud 2 Device messages, Twins or Methods. IoT Hub exposes APIs on the back-end side (easily used with the Service Client SDKs) allowing to use any of those.
C2D messages are used to send raw data to devices, meaning you implement your own "protocol" between cloud and device. C2D messages are also persistent in the Cloud as IoT Hub will retain them (for a certain time defined in settings) if the device is not connected.
Device Twins allows to synchronize a configuration of a device with the Cloud and allows for batch operations on devices (certainly one you want to look closer into).
Device Direct Methods allows to call a function running on a device from the cloud and like Twins supports batch operations.
I have two iOS apps, lets call it Agent app and Customer App.
I have a chat feature between these two apps, but the chats need to be recorded on the server.
I have created two Pusher Apps, one for each of the iOS apps. They both subscribe to their respective private-{id}-channel.
Now every time a message is generated from say Agent app (via HTTP request to server), I want server to create a pusher event with Agent's message on Customer's private channel.
Is it possible to achieve the above using Pusher Private channels?
One way you could achieve this is by having both users join the same channel.
Let's say you have two users: user-a and user-b. Both users subscribe to a common private channel private-chat-user-a-user-b.
let myChannel = pusher.subscribe("private-chat-user-a-user-b")
Then triggering client events on the channel
myChannel.trigger(eventName: "client-my-event", data: ["your": "data"])
Client events are a way of sending messages just between clients, without a server relaying them.
Disclosure: I work at pusher.
I wanted to record the chat on server, therefore, instead of making Customer App directly sending message on Agent App channel, I made the Customer App call my server API, which records the message and relies it on channel that Agent App is listening to.
I Am stuck with integrating the PubNub WebRTC SDK for iOS application.
Its a JavaScript SDK. How To integrate this with my iOS app.
Thanks in advance.....
This does not directly answer the Objective-C implementation, but it might help with understanding the overall solution and the role that PubNub plays.
Why PubNub? - Signaling
WebRTC is not a standalone API, it needs a signaling service to coordinate communication. Metadata needs to be sent between callers before a connection can be established. This metadata includes information such as:
Session control messages to open and close connections
Error messages
Codecs/Codec settings, bandwidth and media types
Keys to establish a secure connection
Network data such as host IP and port
Once signaling has taken place, video/audio/data is streamed directly between clients, using WebRTC’s PeerConnection API. This peer-to-peer direct connection allows you to stream high-bandwidth robust data, such as video. HTML5Rocks provides a great guide on all things WebRTC (no need to read as it is summarize below).
PubNub makes this signaling incredibly simple, and in addition, gives you the power to do so much more with your WebRTC applications.
What PubNub is Not
PubNub is not a server for WebRTC. A signaling service specifies ICE servers that the video chat can stream over. Public STUN servers provided by google can be used, but they are not very reliable. STUN or TURN servers are required to circumnavigate a firewall, else chat will fail. Many services provide the “total package” of signaling and server in one, that is not PN. Our audience are the people who want to build their own, more custom service.
XirSys
XirSys already have a WebRTC-PubNub demo using rails on their GitHub. They host STUN and TURN servers catering to the needs of WebRTC.
Open Source
There are a few open source STUN and TURN server projects that can be downloaded and hosted with ease:
Amazon AWS VM: Pre-made ready to deploy
RFC5766 TURN: Google Code, TURN server
One-to-many: Instructions on MCU for 1-to-many media servers. Necessary for large group chats and streams with hundreds+ users.
So as you can see, we do not provide audio/video streaming services but if you are building this solution, PubNub is a necessary piece to tie it all together with the signal protocol.
AndroidRTC
And here is an PubNub AndroidRTC example by our interns.
I need to create an application that will automatically publish multiple video streams on different youtube channels of my clients.
can I publish applications from one stream to different channels or one application - one channel?
can I concurrently publish several independent live events per channel? what are the restrictions on the number of concurrent events?
By default, for the YouTube Data API v3 i have 3,000.0 units/second/user Per-User Limit. What this means? Do I understand correctly, that every client will be able to see the live broadcast, that i created through this api is not more than 3'000 seconds?