Python reflection - Can I use this to get the source code of a method definition.

Question

Duplicate of..

• How can I get the code of python function?
• print the code which defined a lambda function
• Python: How do you get Python to write down the code of a function it has in memory?

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I have a method definition which is successfully running, but would like to modify it in runtime.

for eg: If i have a method

def sayHello():
    print "Hello"

type(sayHello) gives me the answer 'type function'. Will I able to get the source code string of this function object. Is it considered a security issue ?

Answer 1

You will not be able to get the source code.

This is not a security issue.

In fact, this is not reflection at all.

Answer 2

sayHello.func_code.co_code returns a string that I think contains the compiled code of the method. Since Python is internally compiling the code to virtual machine bytecode, this might be all that's left.

You can disassemble it, though:

import dis

def sayHello():
  print "hello"

dis.dis(sayHello)

This prints:

   1           0 LOAD_CONST               1 ('hello')
               3 PRINT_ITEM
               4 PRINT_NEWLINE
               5 LOAD_CONST               0 (None)
               8 RETURN_VALUE

Have a look at Decompyle for a de-compiler.

Answer 3

There is not a built-in function to get source code of a function, however, you could build you own if you have access to the source-code (it would be in your Python/lib directory).

Answer 4

Use the inspect module:

import inspect
import mymodule
print inspect.getsource(mymodule.sayHello)

The function must be defined in a module that you import.