Friday, 15 September 2017

Web sockets online Tutorial - Page2

Web sockets online Tutorial - Page2

Question: Difference between socket and websocket?
WebSockets run from browsers and connecting to Server over a similar to HTTP. it require a permanent connection to its server.
Sockets are more powerful and generic and not restricted to http protocol OR browser.



Question: How to detect the message type in onmessage event?
  
socket.onmessage = function(event){
   if(typeOf event.data === String ) {
      console.log("Received data string");
   }
}



Question: How does Web Socket support Single TCP Connection?
In Web a new TCP connection is initiated for a each HTTP request and terminated after the response is received which means A new TCP connection need for each HTTP request. Whereas In WebSocket, the HTTP connection is upgraded and client and server communicate over that same TCP connection.


Question: How Web Socket support on Bi-directional?
In Web client(like browser) only can send the request to server then server send the response to the same client only.
Whereas In WebSocket, there is no pattern like request/response and Both (Client/Server) can send message to other party.


Question: How Web Socket support on Full Duplex?
In Web client(like browser) only can send the request to server then server send the response to the same client only. At a given time, either client is talking to server or server is talking to client. Whereas In WebSocket they can talk each other.


Question: What is the WebSocket API?
The WebSocket API is the asynchronous communication from client to server and it takes place over single TCP socket using the ws (unsecure) or wss (secure) protocol and can be used by any client or server application.


Question: How can we secure WebSocket API?
Normal Web Socket API start with ws but secure API start with wss.

Question: What is Ajax Long-Polling?
  1. A client requests a webpage using HTTP.
  2. The server does not immediately respond with the requested information but waits until there's new information available.
  3. When there's new information available, the server responds with the new information.
  4. The client receives the new information and immediately sends another request to the server, re-starting the process.



Question: What is Comet in HTML5?
Comet is a collection of techniques prior to HTML5 which use streaming and long-polling to achieve real time applications.


Question: What is Server Sent Events?
Server Sent Events (SSE) connections can only push data to the browser.
online stock quotes, or twitters updating timeline or feed are good examples of an application that could benefit from SSE.


Question: How to add http headers in Websockets client API?
We can not add custom header in Web sockets.


Question: How can we pass auth while calling Connecting WebSocket?
 var ws = new WebSocket("ws://username:[email protected]/path");



Question: Is PHP support for Web Sockets available?
Yes, for this you need install the library.
Apache Module: https://github.com/disconnect/apache-websocket
PHP WebSocket: http://code.google.com/p/phpwebsocket/
Ratchet: https://github.com/cboden/Ratchet
Wrench: https://github.com/varspool/Wrench


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