Writing entire classes to Python files (and replacing user input)

Question

Basically, I need to write an entire class to a new .py file. The only problem is that two important variables inside the class rely on user input. When I write the class to the file I need to have the actual number/string where the user input is instead. Here is an example of what I currently have:

class CreateClient:
    def writer(self):
        file = open('client_test.py', 'w+')
        file.write(Client)
        print("File created")

class ClientConfig:

    def hostvar(self):
        inhost = str(input('Enter the listener hostname: '))
        return inhost

    def portvar(self):
        inport = int(input('Enter the port: '))
        return inport

class Client:
    def examp(self):
        host = ClientConfig.hostvar(ClientConfig)
        port = ClientCOnfig.portvar(ClientConfig)

As you can see I need Client to be writed to a new file, except it will write

host = ClientConfig.hostvar(ClientConfig)
port = ClientCOnfig.portvar(ClientConfig)

instead of what I need (i.e host='127.0.0.1', port = 9999). Is there any way I can do this, possibly use the operation 'replace'? If I attempt to access the host or port variable by doing Client.examp.host it won't work, so I don't see how I could use replace.

Answer 1

class ClientConfig:
    @staticmethod
    def hostvar():
        inhost = raw_input('Enter the listener hostname: ')
        return inhost
    @staticmethod
    def portvar():
        inport = int(input('Enter the port: '))
        return inport

class Client:
    def examp(self):
        self.host = ClientConfig.hostvar()
        self.port = ClientConfig.portvar()

Example:

>>> client = Client()
>>> client.examp()
Enter the listener hostname: 127.0.0.1
Enter the port: 8000
>>> client.host
'127.0.0.1'
>>> client.port
8000

Note: If you're not going to use self object inside hostvar or hostvar, I strongly recommend using staticmethod.

Answer 2

CreateClient

Here' you're calling file.write(Client) where you pass the class as a parameter. Assuming you want to write the code to another file, this is definitely something you don't want to do, because it just doesn't work*. I suggest you just copy-paste the code yourself into a new file and save it.

_{* This is because, if you want to save python objects, you'll need to convert them into a bytes stream. The best way to do this is using the pickle module, but this is not relevant for your problem}

ClientConfig

Here, you have a choice. As @pramod suggested, you could convert these methods to static. Or, you could leave it be, and I'll show you how to call these accordingly in Client.

Client

Here's a solution for if you don't want to use static methods:

class Client:
    def examp(self):
        c = ClientConfig()
        self.host = c.hostvar()
        self.port = c.portvar()

And the alternative definition for this class, if you want to use static methods has been given by pramod.

---

Creating a new python file [as per requirement]

import random
class CreateClient:
    __client_str = '''class Client:\n\t\n\t\tdef examp(self): self.host = %s; self.port = %d\n'''

    def writer(self):
        c = ClientConfig()
        host = c.hostvar()
        port = c.portvar()
        file = open('client_test%d.py' %random.randint(1, 999999), 'w')
        file.write(CreateClient.__client_str %(host, port))
        print("Client created")
        file.close()

Invocation from within some python script:

import os
os.system("python cilent_test<some_number>.py")