DataFlex

Prevent JavaScript Infinite Loops

See more JavaScript Examples

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

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vSbScript
    Handle hoSbScript
    Handle hoJs
    Variant vResult
    Handle hoResult
    String sTemp1

    Move False To iSuccess

    // This is the JavaScript we'll run:

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

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbScript
    If (Not(IsComObjectCreated(hoSbScript))) Begin
        Send CreateComObject of hoSbScript
    End
    Get ComAppend Of hoSbScript "console.log('Starting infinite loop...'); while(true) {};" To iSuccess

    Get Create (RefClass(cComChilkatJs)) To hoJs
    If (Not(IsComObjectCreated(hoJs))) Begin
        Send CreateComObject of hoJs
    End

    // 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.
    Set ComTimeoutSeconds Of hoJs To 2

    Get Create (RefClass(cComChilkatJsonObject)) To hoResult
    If (Not(IsComObjectCreated(hoResult))) Begin
        Send CreateComObject of hoResult
    End
    Set ComEmitCompact Of hoResult To False

    // Run the script..
    Get pvComObject of hoSbScript to vSbScript
    Get pvComObject of hoResult to vResult
    Get ComEval Of hoJs vSbScript vResult To iSuccess
    If (iSuccess = False) Begin
        // Examine the result for an exception.
        Get ComEmit Of hoResult To sTemp1
        Showln sTemp1

        // 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.
        Get ComLastErrorText Of hoJs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // We should never get here..
    Showln "Succeeded."
    Get ComEmit Of hoResult To sTemp1
    Showln sTemp1


End_Procedure