But in this case, instead of sending an empty response back, the server waits until the data for the client becomes available.If the requested information is not available within the specified time interval, the server sends an empty response to the client, closes, and reestablishes the connection.If no one enters the elevator, it goes to the ground level and in 60 seconds goes up again. But if this elevator went up and waited until someone actually decided to go down (or got tired of waiting), we could call it a long polling mode. If you see an online auction that automatically modifies prices as people bid on items, it looks as if the server pushes the data to you.
The goal is to let individuals and businesses purchase handmade arts and crafts made by children. The goal is to let you see the advantages of changing the protocol for client-server communications on the Web.
For Java developers interested in diving into the server side, we provide the source code and brief comments as a part of the code samples that come with this book.
We show and compare the server-side data push done with server-sent events and Web Socket.
On a low level, web browsers establish a TCP/IP connection for each HTTP session.
Currently there are three basic options that developers use for browser-server communication: polling, long polling, and streaming.