Question

I need help with the following

When you run it like the following:

python3 decorator.py CrocodileLikesStrawberries
The token "CrocodileLikesStrawberries" allows you to interact with the functions.

This code is OK, but there is repetition with the checks for auth_token. We could pull this out into it's own function, but what is even better design is to use a decorator. Create an authorise decorator and use it with the refactored code given below.

import sys

MESSAGE_LIST = []

@authorise
def get_messages():
return MESSAGE_LIST

@authorise
def add_messages(msg):
global MESSAGE_LIST
MESSAGE_LIST.append(msg)

if __name__ == '__main__':
auth_token = ""
if len(sys.argv) == 2:
auth_token = sys.argv[1]

add_messages(auth_token, "Hello")
add_messages(auth_token, "How")
add_messages(auth_token, "Are")
add_messages(auth_token, "You?")
print(get_messages(auth_token))

Answer 1

import sys

MESSAGE_LIST = []
auth_token = ""

def authorise(func):
def validate_token():
global auth_token
"""
Here you can write validation code for token
if(auth_token!="CrocodileLikesStrawberries"):
"""

validate_token()
return func

  
def get_messages():
return MESSAGE_LIST

def add_messages(msg):
global MESSAGE_LIST
MESSAGE_LIST.append(msg)

if __name__ == '__main__':
  
if len(sys.argv) == 2:
global auth_token
auth_token = sys.argv[1]

authorise(add_messages( "Hello"))
authorise(add_messages("How"))
authorise(add_messages("Are"))
authorise(add_messages("You?"))
print(authorise(get_messages()))

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authorise here acts as the required decorator. func calls the method passed as the argument (like add_messages). return func helps in using get_messages calls using authorise. For every call using authorise, validate_token will be called which can be used for token identification. This validation can be put out of decorator and called once using the func reference similar to add_messages.