🔐 Update a file through a Python algorithm (Goolge Cybersecurity Professional Certificate Project)

📝 Project description

In my organization, we control access to restricted content using a list of approved IP addresses. The allow_list.txt file contains these IP addresses. There's also a separate list that includes IP addresses that should be blocked from accessing this content. I created a program to automatically update the allow_list.txt file by removing the IP addresses that are no longer allowed access.

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📂 Open the file that contains the allow list

For the first part of the algorithm, I opened the allow_list.txt file. First, I assigned this file name as a string to the import_file variable:

Then, I used a with statement to open the file:

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📖 Read the file contents

In order to read the file contents, I used the .read() method to convert it into a string.

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🔁 Convert the string into a list

In order to remove individual IP addresses from the allow list, I needed it to be in list format. Therefore, I next used the .split() method to convert the ip_addresses_string into a list:

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🔍 Iterate through the remove list

A key part of my algorithm involves iterating through the IP addresses that are elements in the remove_list. To do this, I incorporated a for loop:

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🧹 Remove IP addresses that are on the remove list

My algorithm requires removing any IP address from the allow list, ip_addresses, that is also contained in remove_list. Because there were not any duplicates in ip_addresses, I was able to use the following code to do this:

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💾 Update the file with the revised list of IP addresses

As a final step in my algorithm, I needed to update the allow list file with the revised list of IP addresses. To do so, I first needed to convert the list back into a string. I used the .join() method for this:

Then, I used another with statement and the .write() method to update the file:

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✅ Summary

I created an algorithm that removes IP addresses identified in a remove_list variable from the allow_list.txt file of approved IP addresses. This algorithm involved:
• Opening the file
• Converting it to a string to be read
• Converting this string to a list stored in the variable ip_addresses
• Iterating through the IP addresses in remove_list
• Removing matches from the list
• Converting the list back into a string using .join()
• Writing the updated content back to the file

⚠️ Disclaimer

This is a hands-on lab from the Google Cybersecurity Professional Certificate. It is hypothetical and created for training purposes only.