New Article: HTML5 Server-Push Technologies, Part 2

We've just published the second and final part of Gregor Roth's series, HTML5 Server-Push Technologies, Part 2. In this part, Gregor goes into detail about the new HTML5 WebSockets protocol, then presents conclusions regarding both WebSockets and Server-Sent Events (covered in detail in Part 1 of the series). Gregor introduces WebSockets as a technology that: enables establishing a bidirectional communication channel. In contrast to Server-Sent Events, the WebSocket protocol is not build on top of HTTP. However, the WebSocket protocol defines the HTTP handshake behaviour to switch an existing HTTP connection to a lower level WebSocket connection. WebSockets does not try to simulate a server push channel over HTTP. It just defines a framing protocol on top of TCP. In this way WebSockets enables two-way communication natively. WebSockets provide a capability to transmit data within a sub-protocol over HTTP. Data is transferred in WebSocket "frames" that include either text (delimited by a starting 0x00 byte and an ending 0xFF byte) or binary data (binary frames start with 0x80 and a set of bytes that define the length in bytes of the binary data that follows). Gregor notes that: Because JavaScript cannot operate with binary data represented as a byte array, the binary frame type is limited to be used for languages other than JavaScript. In addition the binary frame and text frame, new frames types can be introduc...

Date: April, 26 2010
Url: http://www.java.net/blog/editor/archive/2010/04/26/new-article-html5-server-push-technologies-part-2

Others News