I built the server into Java,The server sends (image)data to the web browser through a web socket.So far it works fine.
and I wand that The web browser send data from the server to another web browser (client) using webRTC, So I looked for the webrtc...
I noticed that there are occasions when you need to use webSocket with webRTC
What is the role of websocket in webRTC?
In order to establish a WebRTC connection between two browsers, these browsers will have to negotiate a connection first. To negotiate a connection they need to be able to talk to each other. But they cannot talk to each other because they have not established a connection yet.
That's where a signalling server comes in. That's a server that both peers are already connected to and which can relay messages between them until they have established a connection. Using a websocket connection for this purpose is the most useful way, since it's a (soft) realtime bi-direction communication channel, exactly what you want when relaying messages as quickly as possible.
It doesn't have to be a websocket though; AJAX and/or long-polling will do too, but they have more overhead and are slower, which means it will take longer to negotiate the WebRTC connection.
Related
Assume I have a simple ASP.NET MVC application with an Index view that just shows some static data.
Considering the fact that the web is stateless, when a browser requests for this index.cshtml, a HTTP Get request is made and the server sends the contents of the page to the client.
In Such case is there an entity called connection? If so when can we say that connection is established?
Hope my question is clear.
A connection is established between the client (browser) and the underlying web server (IIS) prior to any invocation of your MVC application.
If you get a request in your web application, then a TCP connection has already been established and an HTTP request has been sent to the server over TCP. With keep-alive semantics, multiple requests may use the same connection, and of course multiple actions could even be called for the same request.
So basically, the establishment of a connection is not something that is particularly useful for a web application to indicate or track, if that is what you are trying to do.
The connection is estabished to the IIS Server/Process and then forwarded to .NET, so the moment IIS receives it, it's 'established'
The HTTP protocol is based on the TCP protocol. Before the GET request is made, a TCP connection must be made.
"The connection is closed" happens when the TCP connection is closed, usually after a single request/response interaction.
The connection may be kept open by using Keep-Alive.
I am trying to understand the purpose of websocket multiplexing extension, the main purpose what the document states is to use a single same origin physical websocket connection to the server while each browser tab uses a logical connection multiplexed on top of physical connection. I see another alternative using which we can accomplish this behavior today, the approach is to launch a shared web worker which opens the websocket connection and let each browser tab send and receive message to/from this worker. i have not tried this yet and i wonder will this work at all.
Your question reflects a misunderstanding of the problem the WebSocket Multiplexing Extension is trying to solve.
The base WebSocket spec (RFC 6455) defines a protocol for bi-directional exchange of data over TCP/IP. A WebSocket starts as a normal HTTP request / response. In this exchange, the client and server negotiate to switch to the WebSocket protocol. After the switch, the client and server exchange data frames over the TCP/IP connection. This creates a bi-directional data stream between client and server.
A drawback of the base protocol is that it supports only a single stream of data flowing in each direction. The multiplexing extension augments the base protocol, by allowing the client and server to create multiple "channels" over the same TCP/IP connection.
So the purpose of the multiplexing extension is to allow multiple WebSocket channels to run over the same TCP/IP connection. That's all.
Having multiple browser tabs (or web workers) share a single TCP/IP connection is just an example of how multiplexed websockets might be used. In standards terminology, it's just "informative" (descriptive), not "normative" (a required part of the spec).
Which is best tcp socket server to testing html5websocket? I developing a html5socket based client that will interact with tcp. So I want first a testing server. I am good in PHP but not in sockets programming. So I used PHPwebsocket downloaded from google code. I tried it using its own client and server for testing but it suddenly disconnects and not work as intended so is there any other socket server to test HTML5 websocket client? Which one is better, I can use a python based, or java based tcp server or if in PHP then that can be more convenient. And please tell me what else I need to test HTML5 websocket. I am newbie in sockets. So my concepts are not so clear.
thanks for any advise.
If you want to self host then:
pywebsocket - Python
jwebsocket - Java
jetty with WebSockets - Java
You could connect to the Pusher hosted WebSocket API to see if you can connect. More information on the endpoints and Pusher protocol here:
http://pusher.com/docs/pusher_protocol
You would need to sign up for a free Pusher sandbox account to do this though.
You say you want to "interact with tcp". Do you have specific protocols in mind? If using JMS, XMPP, or AMQP, the Kaazing WebSocket Gateway provides these industry standard APIs and protocols in the browser out-of-the-box. For example, using JMS, you can build pretty complex messaging applications without a single line of server-side code. Everything can run in the client (typically in JavaScript in the browser).
Here are some examples showcasing the power of extending rich business protocols all the way to the browser.
Also, the Kaazing gateway comes with free development license; fully functional server for up to 50 concurrent connections, no functionality or time restrictions.
I already have a server with port and want to write a web app to get the information form the port. Will this be possible with WebPorts?
The Client doesn't even need to talk back to the server, which is the whole point of websockets I would imagine, but since I already have the ports setup, I might be easier and cleaner to just connect and get the info without having to refresh.
WebSockets are not intended as clear TCP channels over which other existing protocols can be implemented.
WebSockets are designed to allow messages to be sent between a client and server, where an event is raised each time a message is received.
Hence a WebSocket client cannot simply connect to an existing TCP server - that server also has to speak the WebSocket protocol.
You could of course write a WebSocket-based server that does nothing but act as a proxy to existing network services.
I think you want websockify which is a WebSocket to plain TCP socket bridge/proxy. It also allows sending and receiving of binary data with the older version of the WebSocket protocol which hadn't yet added direct binary data support.
Disclaimer: I created websockify.
I'm running a websocket server and asking myself, if it's planed, that clients authentication will be done with handshake in future... draft xxxx maybe :)
Do you have information? I have heard that with draft07 a session id can be sent to server, so maybe that can help to auth the client...
What I'm doing atm is to wait a maximum of 10 seconds, till the clients sends me a message with login header, username and password. But i think this is not "THE" solution. How do you guys out there doing it?
The WebSockets protocol permits standard HTTP authentication headers to be exchanged during the handshake. If you have a WebSockets server that plugs into an existing web server as a module then existing authentication in the web server should already work. Otherwise if you have a standalone WebSockets server then you may need to add the authentication support.
Update
As #Jon points out, unlike normal HTTP/XHR requests, the browser API does not allow you to set arbitrary "X-*" headers for WebSocket connections. The only header value that you can set is the protocol. This is unfortunate. One common solution is to use a ticket based system that relies on existing HTTP mechanism for authorization/authentication and then this ticket is passed along with the websocket connection and validated that way: https://devcenter.heroku.com/articles/websocket-security