I am using WebRTC to make a audio, video and chat application. How on the server side we can check if the peer is still connected.
Actually, I want to check before making audio/video call that the other user end is still connected. I am able to maintain Presence (i.e online/offline) when user logs in or logs out of the application.
Suppose, the network connection drops or got disconnected, I am not able to get any information on the server side. If I can get, then I can communicate to rest of the peers connected.
So, need help how to get the information if the peer is still connected or not. I am using Nodejs and WebRTC in my application.
Socket.IO has a concept of 'rooms' that makes it very handy for building WebRTC signaling servers, and a disconnect event fired when a user disconnects. You can also set up a custom event to be emited when, for example, a user stops a video stream or leaves a page.
You might want to take a look at the codelab at bitbucket.org/webrtc/codelab, which uses Socket.IO for signaling. (Apologies, once again, for shameless self promotion!)
You would need to implement your own logic to do that.
Since you already have the client registering presence you could:
maintain a persistent connection via websockets
implement a polling/keep alive algorithm between your clients and server
Related
I wonder how do I use socket.io properly with my express app.
I have a REST API written in express/node.js and I want to use socket.io to add real-time feature for my app. Consider that I want to do something I can do just by sending a request to my REST API. What should I do with socket.io? Should I send request to the REST API and send socket.io client the result of the process or handle the whole process within socket.io emitter and then send the result to socket.io client?
Thanks in advance.
Question is not that clear but from what I'm getting from it, is that you want to know what you would use it for that you cant already do with your current API?
The short answer is, well nothing really.. Websockets are just the natural progression of API's and the need for a more 'real-time' interface between systems.
Old methods (and still used and relevant for the right use case) is long polling where you keep checking back to the server for updated items and if so grab them.. This works but it can be expensive in terms of establishing a connection, performing a lookup, then closing a connection.
websockets keep that connection open, allowing both the client and server to communicate real time. So for example, lets say you make an update to your backend data and want users to get that update, using long polling you would rely on each client to ping back to the server, check if there is an update and if so grab it. This can cause lags between updates, some users have updated data while other do not etc.
Now, take the same scenario with websockets, you make an update to the backend data, hit submit, this then emits to your socket server. Socket server takes the call, performs the task ( grabs updated data ) and emits it to the users, each connected user instantly gets that update.
Socket servers are typically used for things like real time chats or polling where packets are smaller but they are also used for web games etc. Depending on the size of your payloads will determine how best to send data back and forth because the larger the payload the more resources / bandwidth it will take on the socket server so its something to consider.
I spend already 3 days for reading, watching tutorials about WebSockets, socket.io, node.js and so on.
Basically, I'm a Laravel developer and have just a basic idea about all the rest components.
With regret, after these 3 days I don't have in mind all logic step-by-step of implementing this architecture. I will try to explain what did I understand and you please correct me.
So :
WebSockets - is a bidirectional continuous connection between client and server. It uses another port, and basically it is not a HTTP/S connection.
For making this kind of app like I said, we need one more server, and idk why, but this is Node.js. At this Node.js server we should install socket.io (server-side package) and Redis.
Then, we need to add client-side socket.io (via CDN probably).
At Node.js server we are creating a server.js file where require all modules that we need, like socket.io and Redis. We open a connection for a specific non-used port (as 6001). Then we run this node server.
At front-end we are subscribe-ing to this channel and define method for emitting and listening to the server.
Example :
User1 is connecting to a specific route. User2 as well. User1 type a message for User2, when press Submit, message from User1 is sent to Node.js server, where it is sent in Redis(yes? if yes - Why?), and then Node.js is listening for what to do in this case, and send this message to specific user, or with broadcast to all users except the publisher.
Oh, it's even hard to explain that, too much steps and tehcnologies used.
Can please someone correct my logic? I really want to understand all that process and logic of using this components. Or please, give me some useful articles and videos, may be I didn't saw them. Thanks!
I suggest you read the official docs on how to build chat. Basically what you will have in the end is 2 servers, 1 for your Laravel app and the other for chat (Socket.io) . The key to this is using broadcasters and listening for events on both sides, frontend and backend.
Events are broadcast over "channels", which may be specified as public or private. Any visitor to your application may subscribe to a public channel without any authentication or authorization; however, in order to subscribe to a private channel, a user must be authenticated and authorized to listen on that channel.
I am using webrtc.io to create the socket connections for my audio, video chat application. I want to preserve all the socket connection so that I can send updates to all the end users when the node.js server is restarted.
I am using Mongodb as the database for this application. Is there any way to store in the database and retrieve it back when the server is restarted?
I'm going to give you a common life situation to explain this.
Suppose you have a mobile phone that you cannot make calls from and you can only receive calls.
Someone calls you and you can talk to them, messages pass backwards and forwards on a constant connection. This was better than SMS because you could only respond to an SMS that was sent to you as well but now you have this constant connection to talk freely on.
Now in those statements I just described what Websockets are and the difference between that an Http. Next I'll apply this to what you are asking.
Now suppose on this phone where you can only keep talking on calls you receive from someone else, your battery runs out. You find a power source to plug into and get your phone working again. So do you expect your phone to just suddenly re-establish the call that dropped when your battery ran out?
You do not initiate the connection you are talking about. So you cannot "make the call back" or "re-establish the call". This is a strictly "the customer calls you" scenario.
The best you can do is maintain the session state to the subsequent re-connection "picks up where you left off". But on a hang-up the client has to call you back.
For better availabilty you need to proxy the connection and share over multiple application server nodes, all with access to the same session state.
I have a web based multiplayer game. It happens from time to time that someone is kicked out because server did not get expected message from client. It seems from my logs that client did not disconnect, just did not send message or server did not receive it. My question here is "Does this things happen normally from time to time?" Should i use some kind of callback mechanism to ensure message is delivered and if not send it again or is there some issue that i am not aware?
socket.io already provides ACKs and message ID tracking, on top of TCP.
Also, socket.io uses pings to check the connection. So, if you say that the client is not disconnected, and the server tells that the client is not disconnected, then the connection is still there.
The problem must be situated elsewhere.
Are you sure there is not a bug in either part of the implementation? Showing some code snippets could help, as well as the environment you are using.
I am working on a Chatting application (needs to connect to a server) on iPhone. The sending packet from iPhone shouldn't be a problem.
But I would like to know whether it is possible for iPhone to establish a incoming socket connection to server continuously or forever under mobile environment.
OR What do I need to do to give the connection alive ? Need to send something over it to keep it alive ?
Thanks.
Not sure why you want to have chatting app to have persisted connection... I'd better use SMS like model. Anyways, Cocoa NSStream is based on NSSocket and allows a lot of functionality. Take a look at it.
Response to the question. Here is in a nutshell, what I would do:
Get an authentication token from the server.
this will also take care of user presence if necessary but now we are talking about the state; once presence is known, the server may send out notifications to clients that are active and have a user on their contact list.
Get user's contact list and contact presence state.
When a message send, handle it according to addressee state, i.e. if online, communicate back to the other user, if offline, queue for later delivery or reject.
Once token expires, reject communication with appropriate error and make the client to request a new token.
Communication from server to client, can be based on pull or push model. In first case, client periodically makes a request and fetches all messages. This may sound not good but in reality, how often users compose and send messages? Several times a minute? That's not too much. So fetching may happen every 5-10 seconds.
For push model, client must be able to listen and accept connections.
Finally, check out SIP, session initiation protocol. No need to use full version of it though. Just basic stuff.
This is very rough and perhaps simplified. I don't know the target complexity of your chatting system. For example, the simplest thing can also be that server just enables client to client communication by distributing their end points and clients take care of everything themselves.
Good luck!
Super out of date response, but maybe it will help the next person.
I would use xmppframework and a jabber server.