PowerBuilder

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. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_SbScript
oleobject loo_Js
oleobject loo_Result

li_Success = 0

// This is the JavaScript we'll run:

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

loo_SbScript = create oleobject
li_rc = loo_SbScript.ConnectToNewObject("Chilkat.StringBuilder")
if li_rc < 0 then
    destroy loo_SbScript
    MessageBox("Error","Connecting to COM object failed")
    return
end if
loo_SbScript.Append("console.log('Starting infinite loop...'); while(true) {};")

loo_Js = create oleobject
li_rc = loo_Js.ConnectToNewObject("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.
loo_Js.TimeoutSeconds = 2

loo_Result = create oleobject
li_rc = loo_Result.ConnectToNewObject("Chilkat.JsonObject")

loo_Result.EmitCompact = 0

// Run the script..
li_Success = loo_Js.Eval(loo_SbScript,loo_Result)
if li_Success = 0 then
    // Examine the result for an exception.
    Write-Debug loo_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.
    Write-Debug loo_Js.LastErrorText
    destroy loo_SbScript
    destroy loo_Js
    destroy loo_Result
    return
end if

// We should never get here..
Write-Debug "Succeeded."
Write-Debug loo_Result.Emit()


destroy loo_SbScript
destroy loo_Js
destroy loo_Result