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I'm trying to get the path to a script executing in Rhino. I would prefer to not have to pass in the directory as the first argument. I don't even have a lead on how to get it. I'm currently calling Rhino via

java -jar /some/path/to/js.jar -modules org.mozilla.javascript.commonjs.module /path/to/myscript.js

and would like myscript.js to recognize /path/to as it's dirname, regardless of where I run this script from. The only other related question & suggestion here on StackOverflow is to pass /path/to as an argument, but that is not the solution I am looking for.

Scott R
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2 Answers2

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It's not possible to do what you want.

The ability to detect the source of the script being run by a JavaScript interpreter is not a part of the ECMAScript language specification or the Rhino shell extensions.

However, you could write a wrapper executable program which takes a script path as its argument and executes the script in Rhino (e.g. by calling the appropriate main class) and also providing the script location as an environment variable (or similar).

maerics
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  • Thanks, I was afraid of this. I heard from the grapevine that Rhino devs saw no point in including something like this and it wasn't slated for any release. Unfortunately, Rhino needs it because their implementation of `require` is incomplete. Node.js does provide it, so I thought Rhino might as well. Your suggestion is exactly how it's been implemented for now. – Scott R May 19 '11 at 02:52
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/**
 * Gets the name of the running JavaScript file.
 *
 * REQUIREMENTS:
 * 1. On the Java command line, for the argument that specifies the script's
 *    name, there can be no spaces in it. There can be spaces in other 
 *    arguments, but not the one that specifies the path to the JavaScript 
 *    file. Quotes around the JavaScript file name are irrelevant. This is
 *    a consequence of how the arguments appear in the sun.java.command
 *    system property.
 * 2. The following system property is available: sun.java.command
 *
 * @return {String} The name of the currently running script as it appeared 
 *                  on the command line.
 */
function getScriptName() {
    var scriptName = null;

    // Put all the script arguments into a string like they are in 
    // environment["sun.java.command"].
    var scriptArgs = "";
    for (var i = 0; i < this.arguments.length; i++) {
        scriptArgs = scriptArgs + " " + this.arguments[i];
    }

    // Find the script name inside the Java command line.
    var pattern = " (\\S+)" + scriptArgs + "$";
    var scriptNameRegex = new RegExp(pattern);
    var matches = scriptNameRegex.exec(environment["sun.java.command"]);
    if (matches != null) {
        scriptName = matches[1];
    }
    return scriptName;
}

/**
 * Gets a java.io.File object representing the currently running script. Refer
 * to the REQUIREMENTS for getScriptName().
 *
 * @return {java.io.File} The currently running script file
 */
function getScriptFile() {
    return new java.io.File(getScriptName());
}

/**
 * Gets the absolute path name of the running JavaScript file. Refer to
 * REQUIREMENTS in getScriptName().
 *
 * @return {String} The full path name of the currently running script
 */
function getScriptAbsolutePath() {
    return getScriptFile().getAbsolutePath();
}
Gungwald
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