JS page 6 - Dave's Blog

XSLT Meddler Script

I've made an XSLT Meddler script in my continued XSLT adventures. Meddler is a simple and easy web server that runs whatever JScript.NET code you give it. I wrote a script that takes an indicated XSLT on the server, downloads an indicated XML from the Internet and returns the result of running that XML through the XSLT. This is useful when you want to work with something like the Zune software or IE7's feed platform which only reads feeds over the HTTP protocol. I'll give more interesting and specific examples of how this could be useful in the future.

QuickBase Formula Pretty Printer and Syntax Highlighter

Sarah asked me if I knew of a syntax highlighter for the QuickBase formula language which she uses at work. I couldn't find one but thought it might be fun to make a QuickBase Formula syntax highlighter based on the QuickBase help's description of the formula syntax. Thankfully the language is relatively simple since my skills with ANTLR, the parser generator, are rusty now and I've only used it previously for personal projects (like Javaish, the ridiculous Java based shell idea I had).

With the help of some great ANTLR examples and an ANTLR cheat sheet I was able to come up with the grammar that parses the QuickBase Formula syntax and prints out the same formula marked up with HTML SPAN tags and various CSS classes. ANTLR produces the parser in Java which I wrapped up in an applet, put in a jar, and embedded in an HTML page. The script in that page runs user input through the applet's parser and sticks the output at the bottom of the page with appropriate CSS rules to highlight and print the formula in a pretty fashion.

What I learned:

• I didn't realize that Java applets are easy to use via script in an HTML page. In the JavaScript I can simply refer to publicly exposed methods on the applet and run JavaScript strings through them. It makes for a great combination: do the heavy coding in Java and do the UI in HTML. I may end up doing this again in the future.
• I love ANTLRWorks, the ANTLR IDE, that didn't exist the last time I used ANTLR. It tells you about issues with your grammar as you create it, lets you easily debug the grammar running it forwards and backwards, display parse trees, and other useful things.

URI Addressable Text Adventure Games

This post is about creating a server side z-code interpreter that represents game progress in the URI. Try it with the game Lost Pig.

I enjoy working on URIs and have the mug to prove it. Along those lines I've combined thoughts on URIs with interactive fiction. I have a limited amount of experience with Inform which generates Z-Code so I'll focus on pieces written in that. Of course we can already have URIs identifying the Z-Code files themselves, but I want URIs to identify my place in a piece of interactive fiction. The proper way to do this would be to give Z-Code its own mimetype and associate with that mimetype the format of a fragment that would contain the save state of user's interactive fiction session. A user would install a browser plugin that would generate URIs containing the appropriate fragment while you play the IF piece and be able to load URIs identifying Z-Code files and load the save state that appears in the fragment.

But all of that would be a lot of work, so I made a server side version that approximates this. On the Web Frotz Interpreter page, enter the URI of a Z-Code file to start a game. Enter your commands into the input text box at the bottom and you get a new URI after every command. For example, here's the beginning of Zork. I'm running a slightly modified version of the Unix version of Frotz. Baf's Guide to the IF Archive has lists of IF games to try out.

There are two issues with this thought, the first being the security issues with running arbitrary z-code and the second is the practical URI length limit of about 2K in IE. From the Z-Code standard and the Frotz source it looks like 'save' and 'restore' are the only commands that could do anything interesting outside of the Z-Code virtual machine. As for the length-limit on URIs I'm not sure that much can be done about that. I'm using a base64 encoded copy of the compressed input stream in the URI now. Switching to the actual save state might be smaller after enough user input.

Vegas and New Year

Two and half weeks ago Sarah and I went to Las Vegas where I got to see Jesse, Pat, Chris, and (briefly because he's some kind of big shot too busy for his friends now etc) Grib from college. They're mostly in San Jose and I hadn't seen them for a while so it was a lot of fun to hang out. We all stayed at the MGM which is a nice hotel with some good restaurants. In other Vegas related links, Sarah added Sarah's Las Vegas restaurant reviews to her reviews and Jesse has Jesse's Vegas photos up too.

Sarah and I saw the Blue Man Group (video from a concert) and the Price is Right Live Show. The Blue Man Group was very cool although the music was all rock with a heavy drum focus (not depicted in the videos I linked) which I got a little tired of. But despite that I really enjoyed the show, very funny and I totally recommend it. The Price is Right Live Show is like the regular show on TV except the recording is not televised and its not hosted by Bob Barker or Drew Carey. So folks from the audience are still called up to play the same games and really win prizes. It was advertised as hosted by Todd Newton, B-list game show host, but was instead hosted by JD Roberto who hosted such things as "Reality Remix" and the show "Are You Hot? The Search for America's Sexiest People". The showcase showdown included the 2008 version of my car and thankfully I wasn't picked to compete for that because, well I don't know where they bought the car, but I would have gotten the price very wrong. We sat right next to the stage for that show and had a good time.

For New Years Eve Sarah and I stayed in and watched the glitched Seattle Space Needle fireworks show from a safe distance. On New Years we went to a pot-luck at Todd's house and had a fun time. Todd's place is on the top of a hill and has a lovely view of Washington's snow-capped mountains.

Windows Media Center and Zune Integration Hack

1. Reading through the Win MCE data stored as an XML file in "C:\ProgramData\Microsoft\eHome\Recording\Recordings.xml" and the spec for podcasts I created an XSLT to convert a series from Win MCE data to a podcast.
2. I added a new task to the Scheduled Tasks to run my XSLT using my xsltproc.js script. The task runs a handful of commands that look something like the following:

   C:\windows\system32\wscript.exe C:\users\dave\bin\xsltproc.js C:\Users\Dave\Documents\trunk\development\mce-zune\mce-to-podcast.xslt C:\ProgramData\Microsoft\eHome\Recording\Recordings.xml --param title "The Daily Show With Jon Stewart" --param max 4 --param baseURI "http://groucho/" --param thisRelURI "tds.xml" -o "D:\recorded tv\tds.xml"

   For each TV series I run a command like the above and that outputs a podcast for that series into my "D:\Recorded TV\" directory.
3. Zune only allows http URIs for its podcasts so I installed a web server on my Win MCE server. I'm running Vista Ultimate so it was quick and easy for me to install IIS7 but any Web server will do. Then I pointed it at "D:\Recorded TV\".
4. Once all the above was done I just subscribed to the resulting podcasts via my Web server and viola! Since I'm forced to use a Web server I can even run the Zune software on a machine other than my Win MCE server. You can see a screen-shot above of my Zune software showing my Colbert Report podcast.

XSL Transforms in JavaScript

var createNewXMLObj = function() {
   var result = new ActiveXObject("MSXML2.FreeThreadedDOMDocument");
   result.validateOnParse = false;
   result.async = false;
   return result;
}

var args = WScript.arguments;
var ofs = WScript.CreateObject("Scripting.FileSystemObject");

var xslParams = [];
var xmlStyle = null;
var xmlInput = null;
var inputFile = null;
var outputFile = null;
var error = false;

for (var idx = 0; idx < args.length && !error; ++idx)
   if (args.item(idx) == "-o") {
      if (idx + 1 < args.length) {
         outputFile = ofs.GetAbsolutePathName(args.item(idx + 1));
         ++idx;
      }
      else
         error = true;
   }
   else if (args.item(idx) == "--param" || args.item(idx) == "-param") {
      if (idx + 2 < args.length) {
         xslParams[args.item(idx + 1)] = args.item(idx + 2);
         idx += 2;
      }
      else
         error = true;
   }
   else if (xmlStyle == null) {
      xmlStyle = createNewXMLObj();
      xmlStyle.load(ofs.GetAbsolutePathName(args.item(idx)));
   }
   else if (xmlInput == null) {
      inputFile = ofs.GetAbsolutePathName(args.item(idx));
      xmlInput = createNewXMLObj();
      xmlInput.load(inputFile);
   }

if (xmlStyle == null || xmlInput == null || error) {
   WScript.Echo('Usage:\n\t"xsltproc" xsl-stylesheet input-file\n\t\t["-o" output-file] *["--param" name value]');
}
else {
   var xslt = new ActiveXObject("MSXML2.XSLTemplate.3.0");
   xslt.stylesheet = xmlStyle;
   var xslProc = xslt.createProcessor();
   xslProc.input = xmlInput;

   for (var keyVar in xslParams)
      xslProc.addParameter(keyVar, xslParams[keyVar]);

   xslProc.transform();

   if (outputFile == null)
      WScript.Echo(xslProc.output);
   else {
      var xmlOutput = createNewXMLObj();
      xmlOutput.loadXML(xslProc.output);
      xmlOutput.save(outputFile);
   }
}

Two-for Script File

/* 2> NUL
@echo off
cscript /e:javascript /nologo "%~f0" %*
@goto :eof

    Hello World
        Says 'Hello world.' when you run it.
*/

var outText = 'Hello world.';
WScript.Echo(outText);

C:\Users\davris>helloworld

C:\Users\davris>/*  2>NUL
Hello world.

C:\Users\davris>helloworld
Microsoft (R) Windows Script Host Version 5.7
Copyright (C) Microsoft Corporation. All rights reserved.

Hello world.

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