Links - Server Side Javascript
June 30 2009: AppJet ends its free hosting and shelves AppJet. Adios, amigo !
April 6 2009: server side Javascript content makes its second and final move to its own page.
Tales from the Server Side
See a recent article What Server Side JavaScript Needs.
Helma, the New Champion
Helma is a very small and quick Javascript server also based on Rhino and Jetty, with JDBC and the Jala Javascript Framework, plus a reference application and loads of documentation. The download is actually smaller than AppJet, about 7 Meg zipped jars and text files ( hard to compare exactly ). There are Windows and Linux/OS X versions.
It's very easy to install and get the Helma Welcome application running, not much more difficult than AppJet. With a bit more adventure, the administrative tools include a good SQL database manager, Javascript console and debugger.
The learning curve to get a useful application going is altogether steeper than AppJet. The reward is excellent extensibility and performance, both on the Java and Javascript side. A good serious developers tool, but not a quick-and-easy tool for personal or ( arguably ) for small business web applications.
The licensing of Helma and its components is all over the place: some Apache, some Lesser GNU, some corporate, some 'personal' exclusions, etc. Frankly, I'm not a lawyer ( IANAL ) and I'm not sure what some of them are saying. As these things go, maybe its not too bad. The spirit seems to right, if not the exact wording. It has a fairly large and diverse developer community and that counts.
Note added June 30 2009: I've had a chance to work with Helma as a localhost and like it alot - easy to install, powerful framework, fairly easy to learn.
The downside is that it needs a dedicated server to run Java. In fact, Helma maybe be enough of a reason to make the jump from shared hosting to a VPS or whatever. Some people who had been using the now-defunct AppJet say they will be moving to Helma on a VPS. In fact, Helma was the site level application manager for the old AppJet hosting site running multiple instances of AppJet, so the evolution to Helma is fairly natural.
For an example of running AppJet on Helma, see the AppJet demos at JGate.de.
Jaxer
The Jaxer Javascript Server from Aptana has serious ambitions to be the first really workable, large-scale sever-side Javascript solution. It is not Java based, but is built upon on the SpiderMonkey Javascipt engine in C/C++, in other words, it should be quick.
The stand-alone package for local host development ( about 37 meg ) has its own built-in and preconfigured Apache-Mozilla-Javascript server and seems to be fairly easy to get going for testing and experiments. Runtimes exist for The Big Three ( Microsoft, Linux and the Mac ). Licensing is Apache and Mozilla respectively.
The Jaxer development package is big ( 257 meg ) and oriented to Linux ( see Jaxer for Linux ). For the faint of heart who don't slaver at the opportunity to upload and compile from source a mammoth application on a shared hosting machine, Aptana offers Jaxer hosting on the Aptana Cloud, stating at $20 per month ( as of late March 2009 ).
By the way, if a hosting service for heavy-duty apps offers a plan with less than 256M of memory, you will run into performance problems even under a light load. 256M is minimum.
Now we come to licensing issues ... and an unexpected fact.
Understand that Aptana is a commercial, for-profit corporation and has been so for a long time - they sell software and services for a living. Therefore it must be logically inferred that Jaxer licensing is commercial and closed. Wrong !
The Jaxer component is GLP3, that is a commercial but none the less open GPL license. So there, all you cynics and doubters about the ulterior motives of corporations ... of all three of these platforms, the for-profit corporation has the most explicitly open license. There's a lesson somewhere in this for all of us. ;-)
Note that GPL3 for Jaxer does not get us completely out of the woods- there are other licenses involved as well. Aptana itself is somewhat special as corporations go - they also have a line of free, open source and well-engineered plugins for Eclipse ( like Aptana RadRails ).
About ( the demise of ) Hosting at AppJet
Update June 30 2009: Appjet is ending its hosting service forever, free hosting or otherwise. Too bad, it was fun while it lasted. The original article about AppJet follows, but is no longer relevent.
Speaking of needing a good free Javascript hosting service, AppJet ( instant web programming ) offers free Javascript hosting running the Rhino Javascript engine rather than SpiderMonkey ( it's compiled C-code cousin ).
AppJet has a download of their server for localhost configurations ( 13 meg jar file, 37 meg un-jared ). The important parts of the package are the Java-based Rhino, Jetty HTTP server, Apache Derby database and the Java and JavasScript code for AppJet. If you have Java 1.6 installed and a starter myapp.js file, it couldn't be easier to get working.
The download and localhost configuration is nifty ( which is good ). It's interesting to examine the machinery chugging away behind the curtain, as it were. There is still a significant learning curve to get a useful AppJet application running, so it's a good idea to play around with it on a localhost before signing up for a free account. You can also see the raw speed of AppJet without the vagaries of life on a free hosting service. [ Note: oddly the server seems to be slowest in the middle of the night EST. Is that a first ? ]
See Wikipedia on AppJet. Also see the winner of the Most Minimal Wiki in the World Award at AppJet [ link defunct ].
Licensing is resolutely undeclared.
A link to the fruit of my labors on AppJet [ link defunct ]. The initial impression is that the simple Javascript API and relatively flat architecture of the Java libraries supporting AppJet helps it avoid the sluggishness one associates with Java web frameworks: architectural layers = performance latency. Generally, the more layers the more latency.