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Going beyond JSP with Ruby and Seaside
An anonymous reader writes "The Java community has used JavaServer Pages (JSP) technology through most of the last decade, but signs of rust are starting to show. Longstanding conventions inhibit Java programmers from using Java code within Web pages now. Other languages handle Web development much better than Java. This article discuss how code generation works in Ruby, and it delve into a more radical component-based approach in Seaside."
...that seems to be up and coming in the Ruby world is RJS templates. We're using them for the new indi site and they seem pretty handy. The Javascript to Ruby translation is not perfect, of course, but they make some AJAX-ish things nicer: page.visual_effect :highlight, 'sidebar_heading', :duration =>3.
If you're in the northern Virginia area you might be interested in the next NovaRUG meeting; there'll be a presentation on RJS there. Good times...
The Army reading list
Come on! How many times must we endure these kinds of debates? Just use the right tool for the job. You could say there are signs of nothing but rust on COBOL yet it's still very heavily used in financial applications (back end). There is nothing gained by making inflamatory statements, just state the benefits of Seaside and Ruby and leave other languages out of it.
"The difference between stupidity and genius is that genius has its limits." -- Albert Einstein
I know I'm going to have a hard time convincing the PHP audience of this, but the conventions preventing people from using code in JSP are a good thing. You're going to have a hard time selling me a solution that makes it easier to mix my business logic and presentation, even if it's written in a language I like (like Ruby or Smalltalk).
It's better than JSP? Yay. So is everything else developed in the last ten years (and some systems developed before). The Java community has moved on to alternative presentation technologies -- WebWork, JSF, GWT, and the myriad XSLT frameworks come to mind.
Now, if it's more productive than GWT or JSF...well, then we'll talk. But don't attack the strawman of JSP. That's like saying "Ruby is better than Perl 4!"
One look at the author being Bruce Tate, and you wonder why they didn't just link to his book at the top of the article instead of the bottom. Way to go Brucey!
The main article here says 'there are better languages for web than java', or something to that effect. How irrelevant. This article is about JSP, not Java. One could in theory write a ruby language bytecode compiler/interpreter for Java and use it there.
JSP has issues, yes, but some of us dont even use it for our web VIEWS, which are independent of the java backend, (if you're an architect worth hiring, anyway) -- for which Java is unparalled in doing the job. Try to scale like Java does with Ruby at the backend. Good luck.
I live and work in Switzerland and our sites have to handle 4 or more languages. When Ruby has unicode support built in, I'll take another look at it. Until then, it's Java, python and php for me.
I've never used either JSP or Ruby on Rails, so I can't make any kind of informed comparision. I have, however, done some stuff with Seaside and the article focusses on the HTML generation aspect of it and completely misses what makes Seaside great.
Seaside's HTML generator is (IMHO) kind of clunky, actually. Something like PHP, where you embed the code in an HTML file, is cleaner and simpler. But, if you need Seaside, the HTML generation is going to be a small part of your application.
What makes Seaside so utterly cool is that the back button works.
Let me explain:
In Seaside, you generate your page programmatically and you specify what happens when a link is clicked or a button pressed via a callback.
For example:
html anchorWithAction: [self increase] text: '++'.creates a link. The stuff between the square brackets gets executed when the user clicks the link. In the above example, the current page just gets refreshed. If you want to go to another page, you'd use the "call:" method:
html anchorWithAction: [self call: OtherPage new] text: 'Some other page'.Called components can also return values, so you can call out to another page, get a result and use it in your action:
html anchorWithAction: [self setBackgroundColor: (self call: ColorPicker new)] text: 'Change background color'.So hopefully from this, you can see that Seaside works sort of like a boring GUI toolkit. You design the screens and add callbacks to the controls. When the user clicks on a link or presses a button, the associated callback gets invoked.
This would be pretty simple for all concerned were it not for that pesky back button. In the final example, the callback first takes the user to another page (a ColorPicker component) and then, when the user selects "Okay" in that, returns the result and passes it to "setBackgroundColor:".
But what if the user hits the back key while in the ColorPicker? This happens right in the middle of the callback. Can Seaside unwind the entire callback?
Yes, it can. Backing out Just Works.
But, I hear you say, what if there's information I don't want unwound? Say, a shopping cart?
Simple. You can tell Seaside which objects don't change after a backout.
Aside from the back button, you also get access to your entire programming system in the framework so you can do some pretty powerful things in between those square brackets.
Also, the web server is part of the system so you can bypass the framework and do lower-level stuff. For example, I once wrote an image generator. It analyzed its URL, generated the appropriate GIF and returned it.
Plus, of course, it's written in Smalltalk which is the greatest programming language ever ;-).
Geez - the "Trouble with JSP" article TFA references is over 6 years old(!). Java web development has come a long way since then! Just for starters, thinkg JSP with JSTL or Velocity templates plus your favorite MVC framework. Or how about Struts + Tiles? Saying that JSP is bad because of scriptlets is like saying...ASP.NET is bad because of VBScript.
Longstanding conventions inhibit Java programmers from using Java code within Web pages now.
That's because you don't want to mix business logic with presentation logic. Any "programmatic" logic you need for presentation can be accomplished with the JSTL, hence most people disable scriptlet support. Only novices would advocate placing code into templates. I shouldn't complain though, as I can rely on these novices fucking things up so much that I can always find work replacing their abominations with something scalable and maintainable.