How can I pass a variable in a decorator to function's argument in a decorated function?
34,761
Solution 1
You can't pass it as its own name, but you can add it to the keywords.
def decorate(function):
def wrap_function(*args, **kwargs):
kwargs['str'] = 'Hello!'
return function(*args, **kwargs)
return wrap_function
@decorate
def print_message(*args, **kwargs):
print(kwargs['str'])
Alternatively you can name its own argument:
def decorate(function):
def wrap_function(*args, **kwargs):
str = 'Hello!'
return function(str, *args, **kwargs)
return wrap_function
@decorate
def print_message(str, *args, **kwargs):
print(str)
Class method:
def decorate(function):
def wrap_function(*args, **kwargs):
str = 'Hello!'
args.insert(1, str)
return function(*args, **kwargs)
return wrap_function
class Printer:
@decorate
def print_message(self, str, *args, **kwargs):
print(str)
Solution 2
If you want the argument to be "optionally-injected", only in case the function actually takes it, use something like this:
import inspect
def decorate(func):
def wrap_and_call(*args, **kwargs):
if 'str' in inspect.getargspec(func).args:
kwargs['str'] = 'Hello!'
return func(*args, **kwargs)
return wrap_and_call
@decorate
def func1(str):
print "Works! - " + str
@decorate
def func2():
print "Should work, also."
Comments
-
Japboy almost 4 years
I am in progress to learn Python. Hopefully someone points me to correct way.
This is what I'd like to do below:def decorate(function): def wrap_function(*args, **kwargs): str = 'Hello!' # This is what I want return function(*args, **kwargs) return wrap_function @decorate def print_message(): # I'd like to pass 'str' as mentioned above # to any functions' argument like below: print(str) # 'str' is same as above
Any idea? Thanks in advance.