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What is JSON, JSON-RPC and JSON-RPC-Java?
Michael Clark writes "Seen those funky remote scripting techniques employed by Orkut, Gmail and Google Suggests that avoid that oh so 80's page reloading (think IBM 3270 only slower). A fledgling standard is developing to allow this new breed of fast and highly dynamic web applications to flourish.
JSON (JavaScript Object Notation) is a lightweight data-interchange format with language bindings for C, C++, C#, Java, JavaScript, Perl, TCL and others. It is derived from JavaScript and it has similar expresive capabilities to XML. Perfect for the web as doesn't suffer from XML's bloat and is custom made for our defacto browser language.
JSON-RPC is a simple remote procedure call protocol similar to XML-RPC although it uses the lightweight JSON format instead of XML (so it is much faster).
The XMLHttpRequest object (or MSXML ActiveX in the case of Internet Explorer) is used in the browser to call remote methods on the server without the need for reloading the page.
JSON-RPC-Java is a Java implementation of the JSON-RPC protocol.
JSON-RPC-Java combines these all together to create an amazingly and simple way of developing these highly interactive type of enterprise java applications with JavaScript DHTML web front-ends.
" Click below to read more about it.
"Now is the turning point. Forget that horid wait while 100K of HTML downloads when the application just wanted to update one field on the page.
The XMLHttpRequest object has made it's way into all the main browsers with it's recent introduction into Opera and Konqueror (sans the Konqueror bug).
This new form of web development now works on Internet Explorer 5, 5.5, 6, Mozilla, Firefox, Safari 1.2, Opera 8 Beta and Konqueror 3.3 (with a much needed patch).
Appeal to Konqueror users - please log into the KDE bugzilla and vote on this bug
so you to can experience this wonderful thing.
More details here: http://oss.metaparadigm.com/jsonrpc/ "
So...
repopulate your product page for a new product WITHOUT reloading the whole page.
Put a timer in, and have rotating feature products WITHOUT reloading the whole page on a timer.
Update your totals in your chckout / shopping cart WITHOUT reloading the whole page.
Write an RSS news ticker in html rather than flash...
Basically anything that you might have used flash or an IFrame for, you could do with this, javascript and a DIV tag... Pretty important news (if you write commercial websites)
A1. The idea is to make it transparent to the programmer. You can practically just call a Java method from your JavaScript web application. one line of code is required to export or allow access to a server-side object.
A2. Yes, security is an interesting topic. The Java implementation refered to works on a deny all by default - allow specific objects to specific clients. It does require the programmer to think about what methods they are exposing. I have been using it over HTTPS with selective objects exported to authorized clients (using the existing JAAS Java authorization and Authentication framework), so I believe it can be used in a very secure way.
Well, JSON is a subset of JavaScript object notation, so people who know JavaScript already know this. It's basically a way of transfering structured data between browser and server that is less verbose than XML, and can be eval()ed straight into javacript itself.
Of course, any server receiving this stuff via POST should do the same validity checks it does on anything else it gets from the wire. On the client, IIRC you can only use XMLHttpRequest with the server the document originated from, and neither should you be able to execute script across domains, even within iframes, so the existing browser security model should be sufficient to prevent additional security problems, bugs and exploits notwithstanding...
Yes, although this is an XML DTD discussion. Most DTDs including the XML-RPC and SOAP DTDs don't encode using attribute values but instead using child elements with character data (apparently this is the XML best practice). Much Much bigger.
Also, the JSON takes one line of code to parse and access natively in our defacto web browser language 'JavaScript'.
The second requires a bloated JavaScript XML parser (as this is not built in to many browsers) and CPU intensive processing and a cumbersome API to get the data out. Also try doing 100 RPC calls a second with SOAP in a browser (this can be done with JSON-RPC on a local network - 10ms round trip on simple methods).
This is a server side push framework based on the same idea. It preceded GMail et alia.
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