Xojo Plugin

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. Xojo Plugin

Dim success As Boolean
success = False

// This is the JavaScript we'll run:

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

Dim sbScript As New Chilkat.StringBuilder
success = sbScript.Append("console.log('Starting infinite loop...'); while(true) {};")

Dim js As New Chilkat.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.TimeoutSeconds = 2

Dim result As New Chilkat.JsonObject
result.EmitCompact = False

// Run the script..
success = js.Eval(sbScript,result)
If (success = False) Then
    // Examine the result for an exception.
    System.DebugLog(result.Emit())

    // 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.
    System.DebugLog(js.LastErrorText)
    Return
End If

// We should never get here..
System.DebugLog("Succeeded.")
System.DebugLog(result.Emit())