C++

Prevent JavaScript Infinite Loops

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Demonstrates how prevent infinite loops or prevent the JavaScript from running for a longer amount of time than allowed. C++

#include <CkStringBuilder.h>
#include <CkJs.h>
#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    bool success = false;

    // This is the JavaScript we'll run:

    // console.log('Starting infinite loop...'); while(true) {};

    CkStringBuilder sbScript;
    sbScript.Append("console.log('Starting infinite loop...'); while(true) {};");

    CkJs js;

    // Set a limit on the amount of time (in seconds) the script is allowed to run.
    // If the JavaScript takes longer than this amount of time, then Chilkat kills the script without crashing the host program.
    // The default value of TimeoutSeconds is 0, which indicates no limit.
    // For this example, set a limit of 2 seconds.
    js.put_TimeoutSeconds(2);

    CkJsonObject result;
    result.put_EmitCompact(false);

    // Run the script..
    success = js.Eval(sbScript,result);
    if (success == false) {
        // Examine the result for an exception.
        std::cout << result.emit() << "\r\n";

        // The result contains this:

        // 	{
        // 	  "exception": {
        // 	    "message": "interrupted - JavaScript exceeded the Chilkat.Js.TimeoutSeconds",
        // 	    "stack": [
        // 	      {
        // 	        "func": "<eval>",
        // 	        "file": "<input>",
        // 	        "line": 1,
        // 	        "col": 8
        // 	      }
        // 	    ]
        // 	  }
        // 	}

        // Also examine the LastErrorText.
        std::cout << js.lastErrorText() << "\r\n";
        return;
    }

    // We should never get here..
    std::cout << "Succeeded." << "\r\n";
    std::cout << result.emit() << "\r\n";
    }