I'm trying to create a webrtc data channel between client to server.
(the data is different between each client so i need a unique connection between each client to my server)
After some research i concluded that i need to use a turn server and when a client connects to the turn server on the server side i need to act as the other peer and create the data channel, at least that what i think.
I don't need any signalling only pure webrtc connection.
i tried to use this turn server https://github.com/coturn/coturn
but i will deeply appreciate any working example for server to client data channel without any signalling just pure webrtc.
Thanks A lot!:)
You need a signalling server to interchange SDP between the browser and whatever the browser talks to in order to set up the call.
This signalling server can be the same as your media server - but it doesn't have to be.
If your media server is on the open Internet, you don't need a TURN server. If it's behind another NAT, you'll need one.
You've got it all wrong...
To get WebRTC started, you'll need a signaling server. To be able to connect one browser to another, you first need the two browsers to exchange SDP blobs between them. And for that, you need some signaling server to coordinate this process (also known as offer-answer).
Once you get these messages going via a signaling server, you might end up needing a TURN server (and most likely will need a STUN server - which you get for free from most TURN server implementations). The TURN server will relay your data channel's traffic if the browsers will be unable to communicate directly peer-to-peer.
There are quite a few signaling servers out there for you to use. Here's one to try out: https://github.com/feross/simple-peer
I totally understand what you want to achieve here, in fact we had the same requirement in our project too.
Please have a look at the answer I have at: WebRTC Data Channel server to clients UDP communication. Is it currently possible?
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I have node.js server, and I need to create dynamically updated web page with updating data. So, I thought that sockets are way to go.
But there's one problem. I need to send data from the server to client(to browser).
From my research, it is not really possible to create socket server with the client side JS. It is easy to do it the other way, but to send data only from server to client?
What would be best and easiest way to do that?
You create a webSocket or socket.io connection from your client to your server and your server is the webSocket or socket.io server. Once that connection is established, you can then freely send data either way across the connection, from client to server or from server to client.
This type of architecture is ideal for sending data from your server to a web page to dynamically update the web page as new data arrives.
webSocket is the base transport. socket.io is a layer on top of webSocket that adds a bunch of useful features such as auto-reconnect and structured messages. You can use either from a browser. webSocket support is built-in to the browser. If you want to use the additional features of socket.io, then you include the socket.io client library in your web page.
Here's a listing of some of the additional features socket.io offers over a plain webSocket: Moving from socket.io to raw websockets?.
I am not sure I have fully understood your question.
But, if I got it correctly, in order to have a "socket connection" you need to have two sides - a server and a client.
Use socket.io lib with a lightweight node.js server.
You can take a look at their docs + examples - will be very straight-forward.
If you still having trouble, write.
I'm trying to setup an a cordova plugin for iOS which implements the webrtc functions without using any server and it will only be used on a local network. I know there is this plugin, which looks promising but i have some problems with it.
My plan is not to use a TRUN, STUN or any kind of signaling server.
Maybe you think right now: "Ok this is not possible. No signaling equals no connection." But let me explain first. As pointed out here and
here it's possible to avoid using a TRUN, STUN or ICE server. I think this is a good way to start my project but there is still an open question. How shall the devices find each other if there isn't any kind signaling (in the example they use a Node.js server)? Right now i'm playing with the idea of an QR-Code which contains all the necessary information.
At the end it should look like this (black arrwos are more important):
The idea is that everyone who comes into a room has to scan a QR-Code on the RP and then the device knows the IP, port, etc. of the RP and a WebRTC connection with a DataChannel will be established.
I've been looking for an answer for days now, but due to the fact (or at least one of the reasons) that WebRTC is not even supported on iOS nativly there aren't many WebRTC examples out there which work on iOS and no one for a local network.
So my question is: Am I on the right way or is this not even possible? (I found no example for this anywhere, but if I put all the posts I read together, I think it should be possible.)
First of all, TURN and STUN are not signaling server. Signaling server is the term normally associated with the backend server that let's you relay the messages between two peers before the connection is established. The signaling server is thus used to establish the connection. Once the connection is established, there is no role of the signaling server in the communication, unless you intend to make any changes to the connection parameters.
TURN and STUN servers, on the other hand, are used during the connection establishment process. It helps the two peers find a direct path to each other. So when the connection is established, the peers can talk directly with each other and they don't require the signaling server to relay the messages anymore.
Now coming to your question, short answer is, no, your plan is incomplete.
Here are some changes that you'd need in order to make it work:
QR Code is not adequate to convey all required information. According to this answer, they can store roughly 4kb of maximum data. Thus it is not sufficient to pass all candidates.
Not to mention that WebRTC requires both devices to share the candidates. So, you'd need a display and QR code scanner on the Raspberry PI.
You might want to explore alternatives such as Wifi to allow for two-way data sharing between the device and Raspberry Pi. Once setup, the Wifi connection will act as the Signaling server.
Though I am not well versed in iOS or Raspberry Pi. So I would recommend that you ask a separate question about the choice of communication channel if you are unsure about what to choose. Keep in mind that you need Raspberry Pi to be able to communicate with the device for a short period of time in order to allow WebRTC connection to be established.
Coming to STUN and TURN servers, you may be able to get away without using them. I have seen a few cases when my app is able to establish connection to peers within the local network without STUN and TURN servers.
However, I would strongly recommend that you use at least a STUN server. They are often available for free of charge. Google and Firefox also provide their own STUN servers that you can use in any of your WebRTC apps. You can search on internet to get their details.
TURN servers are required only when the two peers are behind NAT's. In such cases STUN servers are sometimes incapable of finding a direct route between them, and you need the TURN server to relay the audio/video/message stream.
Your plan to establish the WebRTC channel between Raspberry Pi and the phones (the black arrows) seem fine to me. It would help you establish further connections between two phones whenever required.
However, if you eventually decide to implement something like Wifi on your Raspberry Pi, the WebRTC connection may be redundant. After all, you could use Wifi to pass the data back and forth, and don't really need an additional layer of WebRTC channel to do that.
Since you run your app on a local network you don't need STUN and TURN servers. But still you need a signaling server. Signaling can't be done with QR-codes, read more about WebRTC and you will understand why.
But a signaling server can be very simple. Since you have that raspberry pi in your local network, you can use this as your signaling server. Just install node, express and socket.io on it. You need only one simple javascript file, mine is only 23 lines of code. Stop wasting your time with QR-codes and you will have your signaling server up and running in no time. You can look at Google Codelab for an example. Hopes this helps you !!
I have PHP on the server side, and HTML and javascript on the client side.
I am making an app where a stakeholder types a message that is broadcasted to multiple recievers of a group in real time.
I did some research on google and I understand I need to use WebSockets or Comet for real time push notifications. Is WebSocket or Comet mandatory for sending mass notifications to users?
Is my understanding correct? Any references to start with?
If the client is a browser, then the ONLY two ways a standard browser can connect to a server is via an Ajax (e.g. http) request or a webSocket connection. So, if you want a client to get notified of something from the outside world it has to use one of those two mechanisms.
HTTP requests are transitory. The client makes a request of a server, the server responds. HTTP requests are perfect for the client requesting information from the server. They are not very good at the server sending information to the client because normally the client is not connected. There are hacks and work-arounds where the client "polls" the server on some interval and maybe even the server uses longer running requests to try to simulate a "push" type system, but they are sub-optimal hacks at best.
webSockets are continuous connections. The client connects and the connection remains in place for as long as both sides want. This allows either side the ability to send a message to the other side whenever they want. That means the server can "push" data to the client whenever it wants. webSockets are efficient for push connections and are recommended (this is one of the main things they were designed for).
Comet is a library that was originally built for using HTTP to try to "hack" or "simulate" push before webSockets were invented and then before they were widely supported. I can think of no reason why one would want to use Comet instead of a webSocket unless you had such an old browser that webSocket was not supported.
So, if you are trying to do "realtime server push" to a browser, then you must have a continuously connected socket from the client which means webSocket (or something built on top of webSocket like socket.io).
For phone apps where you have access to the phone SDK, you can use the "push" system built into the OS to push some messages from server to client. This isn't quite the same as the two way webSocket channel, but since you asked about "push notifications", the OS push services available in both Android and IOS could also be an option for pushing notifications from server to client. Here's info on iOS notifications and Google Cloud Messaging
As of 2016, one can also use Server-sent events in all modern browsers except Microsoft browsers (not supported yet in Edge or IE) to push data from server to client. Here's a browser compatibility table. Server-sent events use a long lasting HTTP connection, a special MIME type and a supporting client in order to be able to send events from server to client at any time. Unlike webSockets, server-sent events are one way only (from server to client). A client would then use a traditional Ajax call in order to be able to send data to a server (whereas with a webSocket data can be sent either way over the same webSocket connection).
Here's a good description of how server-sent events work: How do server-sent events actually work?
Is your client application a SPA? (Single Page application)?
It's very important because if not, you have to consider that everytime a client change page, connection with websocket server will be lost.
In this case you have to manage a queue because if stakeholder send a multicast request when one client is disconnected, client won't receive nothing.
Polling won't solve this situation too and it's an orrible solution because mobile clients (for example) with typical internet plan, will consume megabytes for unuseful "ping" traffic.
A real example of polling is a child in a car asking his dad every minute if they are arrived to a destination!
So, Is there a solution without using spa?
Yes, using a "shared storage" between stakeholder and clients, and using websocket only for "wake up" online clients saying: Hey there is something new, go to check!
Everytime a client open a page it will receive from backend also not-read notifications, taken from the storage.
When a stakeholder want to notify something, it will just store the notification message in the shared storage and send a "pulse" to notification server.
Notification server will forward the "pulse" to online clients (just in case someone is stuck reading a page).
If a "pulse" is lost because a client is changing page there is no problem because the client will bring notifications from the storage.
Every page will contain this logic:
Retrive number or unread notifications (server side)
Connect to the notification server after 5 seconds (javascript side).
Hope it helps.
I would suggest that using webSockets is a more efficient way compared to other options, why is this? Well when a client receives a notification that there's a change in the server there is no need to create an AJAX call to the server to get that change, it can be sent to the client with the same webSocket connection more easily than AJAX. This means efficient code and a faster running App!
Im looking form something to make socket connection between client, without pass through the server. Is there any node package to do this?. Server only send the other client socket, and the clients recieve and send data to each other..
Or, how can we make the implamantation. We need to make a server in client side, but we dont have node installed in the client..
The closest thing that currently exists in some form is not currently part of socket.io. It is called WebRTC and is implemented in Chrome currently. It allows the browser to connect with other browsers.
http://www.webrtc.org
The question is what kind of application is your client? If you are talking about ordinary webbrowsers you need to think about writing pluings (tough case).
If you are talking about clients you have more control then you should look at technique Puching the hole exploited by Skype or P2P apps.
http://it.slashdot.org/story/06/12/15/191205/how-skype-punches-holes-in-firewalls
In general the server is used for TCP sockets orchestration the acutall comunication go directly.
I write a browser game (php, javascript) and I do not know how to make a callback. necessary that the server itself
found a client and call the function (only had one)
Don't write a browsergame if you don't know the basics! Browsergames are way too complex to learn programming.
If you want to make the server notify a client about something you will need to keep a connection open (search keywords: COMET, long polling) as you cannot initiate connections from the server to clients.
For this I can suggest you using Firebase. It is a API that let you to add cloud Data management that your user clients do. You can use that communication to search for client.
If I understand your question, what you need is a socket. Since you're using PHP and Javascript, a WebSocket might be just what you're looking for. With WebSockets, the connection between the client and the server is persisted, so the server can just push data/messages to any or all of the clients connected to it at any point in time. Likewise, the any client connected to the server can push messages/data up to the server.
Here's a video that describes how it works a bit https://www.youtube.com/watch?v=oJxWhmt5m-o