欢迎来到下一个 pikoTutorial！
通过手动修改函数的实现来更改函数的行为是显而易见的，但是我们可以在应用程序运行时以某种方式搞乱函数的实现吗？让我们将这个过程分为 3 个步骤：
我们先来学习一下如何获取函数的源码：
# Import inspect module
import inspect
# Define some callback function
def function():
print('Do something')
source_code = inspect.getsource(function)
print(source_code)
输出：
def callback():
print('Do something')
现在让我们看看如何将字符串中提供的任意 Python 代码转换为可调用的 Python 对象：
# Source code that we want to execute
source_code = 'print("Hello from the inside of the string!")'
# Wrap the source code into a function definition, so that it can be accessed by name
function_name = 'print_hello'
function_definition = f'def {function_name}():\n {source_code}'
namespace = {}
# Execute code with a function definition within the given namespace, so that the function definition is created
exec(function_definition, namespace)
# Retrieve function from the namespace and save to a callable variable
print_hello = namespace[function_name]
# Call the function
print_hello()
输出：
Hello from the inside of the string!
现在让我们实现一个函数，它将函数指针作为输入并返回一个带有修改后的源代码的可调用对象：
import inspect
def get_hacked_function(function):
# Get the source code of the given function
original_function_source_code = inspect.getsource(function)
# Append a new line to the function source code
modified_function_source_code = f'{original_function_source_code} print("You didn\'t expect me here!")'
# Call the function within the namespace
namespace = {}
exec(modified_function_source_code, namespace)
# Parse function name by taking everything what's between "def " and "(" at the first line
function_name = original_function_source_code.split('(')[0].split()[1]
# Retrieve modified function
modified_function = namespace[function_name]
# Return modified function
return modified_function
是时候测试一下了！
# This is the function passed as an input
def original_function():
print("Hello")
# Call our hacking function
hacked_function = get_hacked_function(original_function)
# Call the modified function
hacked_function()
输出：
Hello You didn't expect me here!
初学者注意事项：请记住，此类实验主要用于教育目的。使用 exec() 函数会带来严重的安全问题，因此不建议在生产环境中使用它。如果您需要修改您无权访问其源代码的函数的行为，请考虑使用函数装饰器。在使用 exec() 之前始终保持谨慎并确保您完全理解安全隐患。
以上是通过更改源代码来破解 Python 函数的详细内容。更多信息请关注PHP中文网其他相关文章！
