CkPython

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. 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())