Project: Building a Browser History Manager

Project: Building a Browser History Manager#

Your task is to create a Python class that simulates the “back” and “forward” history of a web browser. This project is designed to help you understand and apply the principles of linked lists by using a linked-list data structure in Python: collections.deque. Read through this documentation so you understand what functions are available. You should have a good idea of how each of them are implemented and what the runtime of each is.

In a browser, when you go “back,” of course you don’t delete the pages you moved past. They are simply moved to a “forward” history stack. When you click “forward,” pages are moved to the “back” queue. When you visit a new page, the “forward” history is cleared, and the new page is added to the history. This is a perfect use case for a double-ended queue, or deque.

Project Requirements#

You will be implementing a BrowserHistory class in a file called browserhistory.py with the following methods:

Data Structures:#

You will need two deque objects to manage the history:
- self.__back: A deque to store the history of pages you can go back to.
- self.__forward: A deque to store the pages you can go forward to.
You will also need a variable to store the self.__current page.

Functionality:

__init__(): The initializer for your BrowserHistory class. It should initialize the two deque objects and the self.__current variable.
visit(url): This method simulates visiting a new webpage. The current page should go onto the end of .__back. It should also clear the .__forward deque, as a new visit resets the forward history. Finally, it should update .__current to the new url.
back(): This method simulates clicking the “back” button. It should check if the self.__back deque is empty. If it is, you cannot go back further, so it should change nothing and return. If it’s not empty, it should move the current page to the front of the self.__forward deque. Then, it should update the self.__current page by taking the last page from the self.__back deque.
forward(): This method simulates clicking the “forward” button. It should check if the self.__forward deque is empty. If it is, you cannot go forward further, so change nothing and return. If it’s not empty, it should move the current page to the self.__back deque. Then, it should update the self.__current page by taking the first page from the self.__forward deque.
get_history(): This method should return a list that represents the full history in order. It should combine the __back deque, the __current page (which you should mark with an asterisk, like *my_current_page.com), and the __forward deque.
clear_history(): This method should clear __forward, __back, and __current back to the initial state where no sites have been visited.

Example#

Here is a visual illustration of how your deques should change as you call different functions. I’m illustrating the deques using list notation, but of course they’re linked lists, not Python lists (I just don’t want to draw all the boxes).

bh = BrowserHistory()

All fields are initialized as empty.