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Chapter 6: Building a Simple Desktop Youtube Downloader

Estimated time to read: 3 minutes

In this chapter, we will be building from the user interface we've shown on chapter 5. We will be building a simple youtube video downloader using a third-party library. In this chapter, we will exercise more on the concept of classes and objects and usage of a third-party library.

The Interface

We will be using the user interface from the previous chapter:

And so we will also be using the code to build it:

Python
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import tkinter as tk

def download():
    url = txt_url.get()
    print(url)

root = tk.Tk()
root.title('Youtube Downloader')

# Define widgets
lbl_url = tk.Label(root, text='Youtube URL')
txt_url = tk.Entry(root, width=30)
btn_download = tk.Button(root, text='Download', command=download)

# Arrange widgets using geometry manager 'pack'
lbl_url.pack()
txt_url.pack(padx=10, fill='x')
btn_download.pack(pady=5)

root.mainloop()

In the listing above, on line 17, we added the padding for horizontal with padx and the fill='x' to make the entry expand horizontally when the window is resized.

Line 3-5 is a function that we will be dealing with later. For now, it just gets the content of the txt_url entry and prints it to the console, but later, we will using this to add the logic for the download of the best quality video available for the youtube video given.

The library

In this project, we will be using the yt-dlp library. As the other libraries, pytube and youtube-dl is giving some issues, we will be using this one for now.

To install the library:

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pip install yt-dlp

This will install the yt-dlp alongside with other pre-requisite libraries:

  • Brotli
  • certifi
  • mutagen
  • pycryptodomex
  • websockets

Now let's create a new class in a new file. For this let's call it downloader.py or name it anything you want.

downloader.py
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import yt_dlp

class Downloader:
    def __init__(self, url: str):
        self.url = url

    def download(self):
        """
        Download the video.

        Args:
            format_id (str): The format id selected.
        """
        ydl_opts = {
            'format': 'best[ext=mp4]/best'
        }

        with yt_dlp.YoutubeDL(ydl_opts) as ydl:
            ydl.download([self.url])

This class has a constructor that takes url as a required argument so we must pass it in the object initialization from our main code like this.

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downloader = Downloader(url)

So now, our download function would be like below:

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import tkinter as tk
from downloader import Downloader

def download():
    url = txt_url.get()

    downloader = Downloader(url)
    downloader.download()

####
####

Our main.py now will be

main.py
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import tkinter as tk
from downloader import Downloader

def download():
    url = txt_url.get()

    downloader = Downloader(url)
    downloader.download()

root = tk.Tk()
root.title('Youtube Downloader')

# Define widgets
lbl_url = tk.Label(root, text='Youtube URL')
txt_url = tk.Entry(root, width=30)
btn_download = tk.Button(root, text='Download', command=download)

# Arrange widgets using geometry manager 'pack'
lbl_url.pack()
txt_url.pack(padx=10, fill='x')
btn_download.pack(pady=5)

root.mainloop()

Now you can run the program and paste a youtube url in the entry. Then click on the Download button. This will download the video with the best format in your current directory.

In summary, we have tackled the following:

  • Created a new class Downloader
  • Using the third party package yt-dlp
  • Object initialization and usage of the constructor with parameter downloader = Downloader(url)
  • We created a method called download inside our class for downloading

In the next chapter, we will be using a treeview to display the available video formats in a tabulated form so that the user can select (double-click) an item to download, we will also display the progress of download in a progress bar with the help of threading for multitasking.

The code for this chapter can be access on this website's repository or you can directly go into this link https://github.com/alexiusacademia/programming-with-python-course/tree/main/docs/course/chapter6

I hope you gained something from this. For any queries, jsut ask in the comment below. Thanks!

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