CkPython

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. CkPython

import sys
import chilkat

success = False

#  This is the JavaScript we'll run:

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

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

js = chilkat.CkJs()

#  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)

result = chilkat.CkJsonObject()
result.put_EmitCompact(False)

#  Run the script..
success = js.Eval(sbScript,result)
if (success == False):
    #  Examine the result for an exception.
    print(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.
    print(js.lastErrorText())
    sys.exit()

#  We should never get here..
print("Succeeded.")
print(result.emit())

JavaScript

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