Movatterモバイル変換

Khumbo Klein · Abdeladim Fadheli · 16 min read · Updated nov 2022 ·Web Scraping ·GUI Programming

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It's no secret that Python is a powerful and most used programming language. Its versatile nature makes it a popular choice for developers worldwide.

This article is for you if you have fancied building your own MP3 downloader from YouTube video URLs. In this article, we will show you how to harness the power of Python to build your MP3 downloader.

If you want to download videos from YouTube in Python, there is a similartutorial on downloading YouTube videos with the quality you want.

We will walk you through building your own MP3 downloader using Python. We will start by discussing the dependencies you will need for this project. Then, we will move on to designing the graphical user interface for the application. Finally, we will show you how to test the MP3 downloader to ensure it works correctly. So, if you're ready to start, let's dive in!

At the end of this article, we are going to build a snazzy application that looks like this:

We will make every bit of it from the ground up.

Here is the table of contents:

Setting up the Environment

First things first, let us install the primary library that we will use for downloading the audio files, thepytube:

$ pip install pytube

Designing the Graphical User Interface

After installing the required library, let us start the GUI designing process. Create a new Python file and call itmp3_downloader.py; you can name it what you want. Just make sure the file name makes sense. Open it and add the following imports:

from tkinter import *from tkinter import ttkfrom pytube import YouTubefrom tkinter.messagebox import showinfo, showerror, askokcancelimport threadingimport os

Let us break down the imports in the code snippet. We are importing everything fromtkinter; this is done using the* symbol, then we are importingttk fromtkinter, a module for styling the widgets. Frompytube, we are importing theYouTube object; this will help us extract audio from a YouTube video and then download that audio file.

We are also importingmessagebox fromtkinter likeshowinfo,showerror, andaskokcancel. Thethreading library will help the application run tasks concurrently, like running the window and extracting and downloading the audio file simultaneously. Finally, we import theos library; to convert the downloaded audio file to a.mp3 file type.

Designing the Main Window and the Canvas

Now that the necessary imports have been taken care of, let us get right into the GUI designing task; we willstart by designing the main window and the canvas, so just below the imports, add the following code:

# creates the window using Tk() functionwindow = Tk()# creates title for the windowwindow.title('MP3 Downloader')# the icon for the application, this will replace the default tkinter iconwindow.iconbitmap(window, 'icon.ico')# dimensions and position of the windowwindow.geometry('500x400+430+180')# makes the window non-resizablewindow.resizable(height=FALSE, width=FALSE)# creates the canvas for containing all the widgetscanvas = Canvas(window, width=500, height=400)canvas.pack()# this runs the app infinitelywindow.mainloop()

Breaking down the above code snippet, we create the main window using the Tkinter's built-in classTk(); then, we give it a title using thetitle() function. Theiconbitmap() function is used to add an icon to the window that replaces the default Tkinter icon; ensure the icon is located in the same folder as the Python file.

To give the main window dimensions and position, we are using thegeometry() function. For theheight andwidth, we have 500x400, and for positioning the window vertically and horizontally, we have 430+180. We want the window to be non-resizable, so to do that, let us use theresizable() function withheight andwidth both set toFALSE, this will disable the maximize/minimize button on the window.

After taking care of the main window, we create the canvas using theCanvas() function; this is a Tkinter widget that acts as a container for other widgets. We are placing it inside the main window and giving it aheight of 500 and awidth of 400. Finally, to have the main window running infinitely, we use themainloop() function, so the window will be open until the user closes it.

If we run the code, we will get this output:

Though the canvas is not visible, this is how it fits inside the main window:

Defining the Widgets Styles

Before we start creating the widgets inside the canvas, let us, first of all, define the styles. We will use thettk module for this task. Just below the canvas, add this code:

"""Styles for the widgets"""# style for the label label_style = ttk.Style()label_style.configure('TLabel', foreground='#000000', font=('OCR A Extended', 15))# style for the entryentry_style = ttk.Style()entry_style.configure('TEntry', font=('Dotum', 15))# style for the buttonbutton_style = ttk.Style()button_style.configure('TButton', foreground='#000000', font='DotumChe')

The code snippet uses thettk.Style() class to create three style objects. After completing each style, we use theconfigure() function to name the styles; in our case, we have named the stylesTLabel,TEntry, andTButton. The function also takes other arguments likeforeground andfont.

Adding the MP3 Logo and the Downloader Label

Now that we have created the canvas containing all the other widgets and successfully defined the widgets' styles, we can start creating the widgets. We will first add the MP3 logo and the Downloader text. To do this, add the following code just after the styles:

 # loading the MP3 logologo = PhotoImage(file='mp3_icon.png')# creates dimensions for the logologo = logo.subsample(2, 2)# adding the logo to the canvascanvas.create_image(180, 80, image=logo)# the Downloader label just next to the logomp3_label = ttk.Label(window, text='Downloader', style='TLabel')canvas.create_window(340, 125, window=mp3_label)

Let us boil down the code, so we are on the same page. We are loading the icon using the Tkinter built-inPhotoImage() function, and after loading the icon, we give it dimensions utilizing thesubsample() function and add it to the canvas using thecreate_image() function. To position the icon horizontally, we use 180 and 80 vertically.

Just next to the icon, we are adding a label with the text Downloader using thettk.Label() function; this function takeswindow,text, andstyle as arguments. As usual, we are adding it to the canvas as well.

The code's output will be this:

Creating the Label and the Entry

We can now make theEntry, and itsLabel. Below the downloader label, add this code:

# creating a ttk labelurl_label = ttk.Label(window, text='Enter MP3 URL:', style='TLabel')# creating a ttk entryurl_entry = ttk.Entry(window, width=72, style='TEntry')# adding the label to the canvascanvas.create_window(114, 200, window=url_label)# adding the entry to the canvascanvas.create_window(250, 230, window=url_entry)

Here we are creating a label and an entry using thettk.Label() andttk.Entry() functions, these two widgets are added to the canvas using the canvascreate_window() function.

Running the above code, we get the following output:

So far, so good; the application is taking shape.

Creating the Progress Label and Progress Bar

Since we want the download progress to be displayed, we will add a label for displaying the download percentage and the file size, and there will be a progress bar just below it:

# creating the empty label for displaying download progressprogress_label = Label(window, text='')# adding the label to the canvascanvas.create_window(240, 280, window=progress_label)# creating a progress bar to display progressprogress_bar = ttk.Progressbar(window, orient=HORIZONTAL, length=450, mode='determinate')# adding the progress bar to the canvascanvas.create_window(250, 300, window=progress_bar)

In the above code, we are creating a default Tkinter label using theLabel() function; it takes a window and an empty string as text. Then we make a progress bar using thettk.Progressbar() function; this function takes four arguments:window,orient,length, andmode. After creating these widgets, we add them to the canvas.

With the above code added, this is what we get now:

Making the Download MP3 Button

Reaching this far, we only have the download button left, so below the progress bar, add the following:

# creating the buttondownload_button = ttk.Button(window, text='Download MP3', style='TButton')# adding the button to the canvascanvas.create_window(240, 330, window=download_button)

The code above is straightforward; we are creating a button using thettk.Button() function and the arguments the function is taking arewindow,text, andstyle. Finally, we are adding it to the canvas.

The code will give us the following output:

Let us finish off the GUI design by making it possible for the application to ask the user whether to close it; we do not want the application to close without the user's confirmation. Just below the imports, add this code:

# the function for closing the applicationdef close_window():    # if askokcancel is True, close the window    if askokcancel(title='Close', message='Do you want to close MP3 downloader?'):        # this distroys the window        window.destroy()

Here, theclose_window() function will destroy the window via thedestroy() function if theaskokcancel isTrue, if it isFalse, the window will still be running. For this function to be triggered, we need to connect it to the window itself. Below this line:

window = Tk()

Add this line of code:

# this will listen to the close window eventwindow.protocol('WM_DELETE_WINDOW', close_window)

Theprotocol() function takesWM_DELETE_WINDOW and theclose_window() function. The logic behind all this is that theprotocol() function will listen to the close window event. If the user clicks the window'sclose button, theclose_window() function will be triggered.

Let us test and see how the application will work after the modification:

If the user clicksOK, theaskokcancel value will beTrue thereby calling thedestroy() function.

Implementing the Download MP3 File Functionality

Having successfully designed the graphical user interface, we will now focus on implementing the download MP3 functionality. Below theclose_window() function, paste this code:

# the function to download the mp3 audiodef download_audio():    # the try statement to excute the download the video code    # getting video url from entry    mp3_link = url_entry.get()    # checking if the entry and combobox is empty    if mp3_link == '':        # display error message when url entry is empty        showerror(title='Error', message='Please enter the MP3 URL')    # else let's download the audio file      else:        # this try statement will run if the mp3 url is filled        try:            # this function will track the audio file download progress            def on_progress(stream, chunk, bytes_remaining):                # the total size of the audio                total_size = stream.filesize                # this function will get the size of the audio file                def get_formatted_size(total_size, factor=1024, suffix='B'):                    # looping through the units                    for unit in ["", "K", "M", "G", "T", "P", "E", "Z"]:                        if total_size < factor:                            return f"{total_size:.2f}{unit}{suffix}"                        total_size /= factor                    # returning the formatted audio file size                    return f"{total_size:.2f}Y{suffix}"                                    # getting the formatted audio file size calling the function                formatted_size = get_formatted_size(total_size)                # the size downloaded after the start                bytes_downloaded = total_size - bytes_remaining                # the percentage downloaded after the start                percentage_completed = round(bytes_downloaded / total_size * 100)                # updating the progress bar value                progress_bar['value'] = percentage_completed                # updating the empty label with the percentage value                progress_label.config(text=str(percentage_completed) + '%, File size:' + formatted_size)                # updating the main window of the app                window.update()                            # creating the YouTube object and passing the the on_progress function            audio = YouTube(mp3_link, on_progress_callback=on_progress)                 # extracting and downloading the audio file             output = audio.streams.get_audio_only().download()            # this splits the audio file, the base and the extension            base, ext = os.path.splitext(output)    # this converts the audio file to mp3 file            new_file = base + '.mp3'    # this renames the mp3 file            os.rename(output, new_file)            # popup for dispalying the mp3 downlaoded success message            showinfo(title='Download Complete', message='MP3 has been downloaded successfully.')            # ressetting the progress bar and the progress label            progress_label.config(text='')            progress_bar['value'] = 0                   # the except will run when an expected error occurs during downloading        except:            showerror(title='Download Error', message='An error occurred while trying to ' \                    'download the MP3\nThe following could ' \                    'be the causes:\n->Invalid link\n->No internet connection\n'\                     'Make sure you have stable internet connection and the MP3 link is valid')                # ressetting the progress bar and the progress label            progress_label.config(text='')            progress_bar['value'] = 0

We are creating thedownload_audio() function in which we are getting the mp3 URL via theget() function, and we have an if statement that checks whether the entry is empty. If it is empty, we display an errormessagebox. Otherwise, execute theelse statement. Inside the else statement, we have thetry/except block. Inside the try statement, that is where the actual downloading is happening.

We have theon_progress() function with thestream,chunk, andbytes_remaining as arguments, this function will track the downloading progress. Inside theon_progress() function, we have another function calledget_formatted_size(), which is for formatting the MP3 file size into a human-readable format like KBs, MBs, GBs, TBs, etc.

After theget_formatted_size() function, theon_progress() gets the formatted size by calling theget_formatted_size() and calculates the bytes downloaded and the percentage completed. The bytes downloaded and the percentage completed are added to the empty progress label and progress bar, respectively. After all this, we are updating the window via theupdate() function.

Now outside theon_progress() function, we are creating theYouTube object which takes the mp3 URL and theon_progress() function. After that, we extract the audio file from an MP4 file and download it via this line of code:

output = audio.streams.get_audio_only().download()

So to convert this audio file in MP4 file format to an actual MP3 file, we are using this line of code:

# this splits the audio file, the base and the extensionbase, ext = os.path.splitext(output)# this converts the audio file to mp3 filenew_file = base + '.mp3'# this renames the mp3 fileos.rename(output, new_file)

After successfully downloading the audio file and converting it to MP3, the application displays a successful message to the user, and the progress label and progress bar are reset.

Having managed to create thedownload_audio() function, let us now create another function and call itdownloadThread(). The primary purpose of this function is that we want it to run thedownload_audio() function as a thread since it handles a lot of tasks at once. So below thedownload_audio() function, paste these lines of code:

# the function to run the download_audio function as a thread   def downloadThread():    t1 = threading.Thread(target=download_audio)    t1.start()

Here we are simply creating a thread using theThread() class; the thread'starget is thedownload_audio() function. To start the thread, we are using thestart() function.

We are almost there to download our first MP3 file; the only task that we are remaining with is binding theDownload MP3 button with thedownloadThread() function, to do that, edit thedownload_button and make it look like this:

download_button = ttk.Button(window, text='Download MP3', style='TButton', command=downloadThread)

Here when the user clicks the button, thedownloadThread() function will be triggered, this, in the end, will call thedownload_audio() function and run it as a thread.

Open the application and paste the URL for the YouTube video whose audio file you want to download in the entry field and click the button; if the download was successful, you will get the output like this:

If you check the project's folder, you will see there is an MP3 file:

Suppose the user clicks the button without entering the URL; the application will produce this output:

If the user enters an invalid URL, this is the output to expect:

And in case we have a broken or unstable internet connection when the actual download is in progress, this is the output we get:

Well, the application seems to be working perfectly!

Note:Something worthy of your attention and worth mentioning here, some YouTube videos whose MP3 files you want to download will not be downloaded if the video is a live stream, is not allowed, is unavailable in your region, or is a premium video, etc.

Conclusion

Building an MP3 downloader is a great way to learn and master many Python concepts. This article has provided a step-by-step guide on how to do this. We now hope you have learned a lot from this article and will apply the knowledge gained in your future Python projects.

Get the complete codehere.

Learn also:How to Make a YouTube Video Downloader in Python.

Happy coding ♥

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