Challenge: Proxy Pattern

In this challenge, you have to implement the proxy pattern to solve the given problem.

We'll cover the following

Problem statement #

In this challenge, you have to implement a library kiosk. The LibraryKiosk allows a student to perform two functions:

  • open: allows the student to open an app in the kiosk.

  • connectTo: allows the student to connect to a website.

The definitions for both the functions are given to you. Currently, using these two functions, the student can open up any app and connect to any website:

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class LibraryKiosk{
    open(app){
        console.log(`Opening ${app}`)
    }    
    connectTo(website) 
    { 
        console.log("Connecting to "+ website); 
    } 
}
var libraryKiosk = new LibraryKiosk()
libraryKiosk.open("photos")
libraryKiosk.open("settings")
libraryKiosk.open("chrome")
libraryKiosk.connectTo("fb.com")

Your task is to implement the proxy pattern so that it restricts access to a few apps/websites for students. You need to implement the functions such that the student cannot open the following apps:

  • camera, photos, music, and settings

Similarly, the student should not be able to connect to the following websites:

  • fb.com, instagram.com, snapchat.com, google.com, and gmail.com

Apart from the apps mentioned above and websites, the student can access the rest.

Input

Accessing different apps and connecting to websites

Output

Users can only open and connect to the allowed apps/websites

Sample input

var libraryKiosk = new ProxyLibraryKiosk(); 
libraryKiosk.open("photos")
libraryKiosk.open("music")
libraryKiosk.open("Chrome")
libraryKiosk.connectTo("booksportal.com"); 
libraryKiosk.connectTo("google.com"); 
libraryKiosk.connectTo("fb.com");

Sample output

"You can't access the photos"

"You can't access the music"

"Opening Chrome"

"Connecting to booksportal.com"

"Access to google.com denied"

"Access to fb.com denied"

Challenge #

Take a close look and design a step-by-step solution before jumping on to the implementation. This problem is designed for your practice, so try to solve it on your own first. If you get stuck, you can always refer to the solution provided. Good Luck!

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class LibraryKiosk{
    open(app){
        console.log(`Opening ${app}`)
    }
    connectTo(website){
         console.log("Connecting to "+ website); 
    }
}

Let’s discuss the solution in the next lesson.