How can you run Javascript using Rhino for Java in a sandbox?

Question

Part of our java application needs to run javascript that is written by non-developers. These non-developers are using javascript for data formatting. (Simple logic and string concatenation mostly).

My question is how can I setup the execution of these scripts to make sure scripting errors don't have a major negative impact on the rest of the application.

• Need to guard against infinite loops
• Guard against spawning new threads.
• Limit access to services and environment
  • File system (Example: If a disgruntled script writer decided to delete files)
  • Database (Same thing delete database records)

Basically I need to setup the javascript scope to only include exactly what they need and no more.

Answer 1

To guard against infinite loops, you can observe the instruction count as the script runs (this works only with interpreted scripts, not with compiled ones).

There is this example in the Rhino JavaDocs to prevent a script from running for more than ten seconds:

 protected void observeInstructionCount(Context cx, int instructionCount)
 {
     MyContext mcx = (MyContext)cx;
     long currentTime = System.currentTimeMillis();
     if (currentTime - mcx.startTime > 10*1000) {
         // More then 10 seconds from Context creation time:
         // it is time to stop the script.
         // Throw Error instance to ensure that script will never
         // get control back through catch or finally.
         throw new Error();
     }
 }