My class Test below can have multiple functions, in this example, one of the functions is put_in_db(). My class expects a JSON object that will get converted to the dictionary and will be passed to invoke_func. Now, within invoke_func, how can I invoke different functions using the key functional_call and the parameters list using params. I have chosen params as a list so that the order is maintained. I cannot change put_in_db() function since this can be from an external class too.

class Test:
    def __init__(self):
        print("Test initialized")
        
    def put_in_db(name, age):
        print("put in db")
        
    def invoke_func(self, my_dict):
        print(my_dict)
        function_call = my_dict.get('functional_call')
        params = my_dict.get('params')
        print(params)
        '''
        how to invoke put_in_db from here using function_call 
        and params
        '''
        
if __name__ == "__main__":
    T = Test()
    data = {'functional_call': 'put_in_db', 'params': [{'name': 'Saf', 'age': '81'}]}
    T.invoke_func(data)

CodePudding user response：

You can use exec():

def invoke_func(self, my_dict):
    print(my_dict)
    function_call = my_dict.get('functional_call')
    params = my_dict.get('params')
    print(params)
    exec(f'{function_call}({params})')

Note: exec() does have security vulnerabilities, as it will execute any code that is passed to it, so exercise caution when the user inputs something that is then executed.

CodePudding user response：

class Test:
    def __init__(self):
        print("Test initialized")
        
    def put_in_db(self,name, age):
        print(f"put {name}, age {age}, in db")
        
    def invoke_func(self, my_dict):
        print(my_dict)
        function_call = my_dict.get('functional_call')
        params = my_dict.get('params')
        print(params)
        getattr(self,function_call)(**params)
        
if __name__ == "__main__":
    T = Test()
    data = {'functional_call': 'put_in_db', 'params': {'name': 'Saf', 'age': '81'}}
    T.invoke_func(data)

getattr(some_object, att_name) will grab the attribute att_name from some_object, assuming it exists (if not it will give an AttributeError unless you also include a default). Then you can just invoke it by unpacking params as an argument.

I made two other changes to your code:

1. You left out self from your put_in_db method.
2. You made param a list containing a dict, but it's easier to work with if you just make it a dict.

You will probably want to add some error checks error checks for if/when someone passes in an string that doesn't correspond to an attribute.