Accuknox Assignment

[MohammadSufiyan1]

                         '''Django Signal'''

'''Question 1: By default are Django signals executed synchronously or asynchronously? By default, Django signals are executed synchronously. This means that when a signal is sent, the code that sends the signal will wait for the signal handlers to finish executing before continuing. Here's a code snippet that demonstrates this'''

import time from django.dispatch import signal

my_signal = signal(providing_args=["sender"])

def signal_handler(sender, **kwargs): print("Signal handler started") time.sleep(2) # Simulate some long-running task print("Signal handler finished")

my_signal.connect(signal_handler)

print("Sending signal...") my_signal.send(sender="sender") print("Signal sent")

'''If you run this code, you'll see that the output is'''

Sending signal...

Signal handler started

Signal handler finished

Signal sent

'''As you can see, the code that sends the signal (my_signal.send) waits for the signal handler to finish executing before printing "Signal sent". This demonstrates that Django signals are executed synchronously by default'''

'''Question 2: Do Django signals run in the same thread as the caller? Yes, Django signals run in the same thread as the caller. This means that when a signal is sent, the signal handlers will execute in the same thread as the code that sent the signal. Here's a code snippet that demonstrates this'''

import threading from django.dispatch import signal

my_signal = signal(providing_args=["sender"])

def signal_handler(sender, **kwargs): print(f"Signal handler thread: {threading.current_thread().name}")

my_signal.connect(signal_handler)

print(f"Main thread: {threading.current_thread().name}") print("Sending signal...") my_signal.send(sender="sender") print("Signal sent")

'''If you run this code, you'll see that the output is'''

Main thread:MainThread

Sending signal...

Signal handler thread: MainThread

Signal sent

'''As you can see, the signal handler runs in the same thread as the main thread that sent the signal'''

'''Question 3: By default do Django signals run in the same database transaction as the caller? Yes, Django signals run in the same database transaction as the caller. This means that if a signal handler raises an exception, it will roll back the entire transaction, including any changes made by the code that sent the signal. Here's a code snippet that demonstrates this'''

from django.db import transaction from django.dispatch import signal

my_signal = signal(providing_args=["sender"])

def signal_handler(sender, **kwargs): print("Signal handler started")

Simulate some database operation that fails

try:
    MyModel.objects.create(name="test")
    raise ValueError("Simulated error")
except ValueError:
    print("Signal handler error")

@transaction.atomic def send_signal(): print("Sending signal...") my_signal.send(sender="sender") print("Signal sent")

send_signal()

'''If you run this code, you'll see that the output is'''

Sending signal...

Signal handler started

Signal handler error

'''And if you check the database, you'll see that no changes were made, because the entire transaction was rolled back when the signal handler raised an exception.'''

               '''Custom Classes in Python'''

'''Here is a Python implementation of the Rectangle class that meets the requirements'''

class Rectangle: def init(self, length: int, width: int): self.length = length self.width = width

def __iter__(self):
    yield {'length': self.length}
    yield {'width': self.width}

'''Here's a breakdown of the implementation. The init method initializes the length and width attributes of the Rectangle instance. The iter method is a special method in Python that allows an object to be iterable. In this case, we use the yield keyword to define a generator that returns two dictionaries: one with the length attribute and another with the width attribute. Here's an example usage of the Rectangle class'''

rect = Rectangle(4, 5)

for attr in rect: print(attr)

Output:

{'length': 4}

{'width': 5}