Youtube Subtitles Downloader Flask App - Interesting Project - 2024

In today’s blog, we will build a Youtube Subtitles Downloader Flask App which we can later deploy on the web for free either on Heroku or Pythonanywhere.

Check out the video here – https://youtu.be/N7-mR8jfP-U

Table of Contents

Sneak Peek at our Youtube Subtitles Downloader Flask App

Subtitles in XML Format

This is going to be a very interesting blog, so without any further due, let’s do it…

Step 1 – Importing required libraries

Importing required libraries for our Youtube Subtitles Downloader Flask App.

import cv2
import os
import requests
from fpdf import FPDF
from flask import Flask,request,render_template

Step 2 – Getting API_KEY from RapidAPI

Get your API KEY, API HOST, and links from RapidAPI.
Open RapidAPI and search for YouTube Media Downloader.
Now click on Subscribe to Test and Subscribe to the Basic Plan which is FREE 🙂

Now copy your API_KEY, API_HOST, and video_details_url from here.
For subtitle_details_url click on Translate, Convert, and Download Subtitle in the most left corner and again copy the URL from there.
Finally, define the Flask app.

API_KEY = "YOUR API KEY"
API_HOST = "youtube-media-downloader.p.rapidapi.com"
video_details_url = "https://youtube-media-downloader.p.rapidapi.com/v2/video/details"
subtitle_details_url = "https://youtube-media-downloader.p.rapidapi.com/v2/video/subtitles"

app = Flask(__name__)

Step 3 – Function for getting VideoID

This function will simply extract the VideoID from the URL.
Suppose the URL is https://www.youtube.com/watch?v=abc123 then the videoID here will be abc123.

def get_video_id(videoURL):
    # split YouTube URL by '/' so we can get its ID
    videoID = str(videoURL).split('/')
    # get the last part of the list which is the ID
    videoID = videoID[-1]
    if '=' in videoID:
        videoID = videoID.split('=')[-1]
    if not videoID[0].isalpha():
        videoID = videoID[1:]
    print(videoID)
    return videoID

Step 4 – Function for getting Video Details

This function takes the videoID and returns the subtitle URL for the video.
This URL will show the subtitles in XML format.

def get_video_detail(videoID):
    # access the API
    url = video_details_url
    headers = {
        'x-rapidapi-host': API_HOST,
        'x-rapidapi-key': API_KEY
    }
    # send a get request to the API 
    querystring = {"videoId": videoID}
    response = requests.request("GET", url, headers=headers, params=querystring)
    # conver the response to json format
    json_response = response.json()
    # obtain the subtitle url (in XML format)
    try:
        subtitleURL = json_response['subtitles']['items'][0]['url']
        print(subtitleURL)
        return subtitleURL
    except:
        print('No subtitles in this video...')
        return None

Step 5 – Function for getting Subtitle Text

Now we will extract Text from this URL which is having subtitles in XML format.

def get_subtitle_text(subtitleURL):
    # access the API
    url = subtitle_details_url
    headers = {
        'x-rapidapi-host': API_HOST,
        'x-rapidapi-key': API_KEY
    }
    # send a get subtitle text request to the API 
    querystring = {"subtitleUrl": subtitleURL}
    response = requests.request("GET", url, headers=headers, params=querystring)
    # return the text response
    return response.text

Step 6 – Function for Downloading Subtitle File

This function will help us put subtitle text in a PDF File and download it.

def Convert_And_Download_Subtitle(text):
    # create a pdf object
    pdf = FPDF()
    # add a page to the pdf
    pdf.add_page()
    # set font and size of the font
    pdf.set_font("Arial", size=12)
    # for evey line in the text
    for line in text.split('\n'):
        # add the line to the pdf
        pdf.cell(200, 5, txt=line, ln=1)
    
    # save and download the pdf with a custom file name
    pdf.output("subtitle.pdf")
    print('Subtitles PDF Saved!!!')

Step 7 – Defining Routing Functions for our Flask App

home() function will render home.html as our homepage.
downloadsubs() will take the URL, extract its VideoID, extract its Subtitle URL, extract Subtitle text from the URL, put it in a PDF File, and finally save it.

@app.route('/')
def home():
    return render_template('home.html')

@app.route('/downloadsubs',methods=['POST'])
def downloadsubs():
    if request.method == 'POST':
        videoURL = request.form['yturl']
        videoID = get_video_id(videoURL)
        subtitleURL = get_video_detail(videoID)
        if subtitleURL:
            subtitles = get_subtitle_text(subtitleURL)
            Convert_And_Download_Subtitle(subtitles)

    return render_template('home.html',url=subtitleURL,subtitletext=subtitles)


if __name__ == '__main__':
    app.run(debug=True)

Final Look of our Youtube Subtitles Downloader Flask App

Subtitles in XML Format

To download subtitles in XML format, right-click and click ‘Save As’.

Downloaded PDF Subtitle File

Code files for our Youtube Subtitles Downloader Flask App

app.py

import cv2
import os
import requests
from fpdf import FPDF
from flask import Flask,request,render_template

API_KEY = "YOUR API KEY"
API_HOST = "youtube-media-downloader.p.rapidapi.com"
video_details_url = "https://youtube-media-downloader.p.rapidapi.com/v2/video/details"
subtitle_details_url = "https://youtube-media-downloader.p.rapidapi.com/v2/video/subtitles"

app = Flask(__name__)

def get_video_id(videoURL):
    # split YouTube URL by '/' so we can get its ID
    videoID = str(videoURL).split('/')
    # get the last part of the list which is the ID
    videoID = videoID[-1]
    if '=' in videoID:
        videoID = videoID.split('=')[-1]
    if not videoID[0].isalpha():
        videoID = videoID[1:]
    print(videoID)
    return videoID

def get_video_detail(videoID):
    # access the API
    url = video_details_url
    headers = {
        'x-rapidapi-host': API_HOST,
        'x-rapidapi-key': API_KEY
    }
    # send a get request to the API 
    querystring = {"videoId": videoID}
    response = requests.request("GET", url, headers=headers, params=querystring)
    # conver the response to json format
    json_response = response.json()
    # obtain the subtitle url (in XML format)
    try:
        subtitleURL = json_response['subtitles']['items'][0]['url']
        print(subtitleURL)
        return subtitleURL
    except:
        print('No subtitles in this video...')
        return None
        
def get_subtitle_text(subtitleURL):
    # access the API
    url = subtitle_details_url
    headers = {
        'x-rapidapi-host': API_HOST,
        'x-rapidapi-key': API_KEY
    }
    # send a get subtitle text request to the API 
    querystring = {"subtitleUrl": subtitleURL}
    response = requests.request("GET", url, headers=headers, params=querystring)
    # return the text response
    return response.text

def Convert_And_Download_Subtitle(text):
    # create a pdf object
    pdf = FPDF()
    # add a page to the pdf
    pdf.add_page()
    # set font and size of the font
    pdf.set_font("Arial", size=12)
    # for evey line in the text
    for line in text.split('\n'):
        # add the line to the pdf
        pdf.cell(200, 5, txt=line, ln=1)
    
    # save and download the pdf with a custom file name
    pdf.output("subtitle.pdf")
    print('Subtitles PDF Saved!!!')

@app.route('/')
def home():
    return render_template('home.html')

@app.route('/downloadsubs',methods=['POST'])
def downloadsubs():
    if request.method == 'POST':
        videoURL = request.form['yturl']
        videoID = get_video_id(videoURL)
        subtitleURL = get_video_detail(videoID)
        if subtitleURL:
            subtitles = get_subtitle_text(subtitleURL)
            Convert_And_Download_Subtitle(subtitles)

    return render_template('home.html',url=subtitleURL,subtitletext=subtitles)


if __name__ == '__main__':
    app.run(debug=True)

home.html

<!doctype html>
<html lang="en">

<style type='text/css'>
    body {
        font-family: sans-serif;
        margin-top: 40px;
    }

    .regform {
        width: 800px;
        background-color: rgb(0, 0, 0, 0.8);
        margin: auto;
        color: #FFFFFF;
        padding: 10px 0px 10px 0px;
        text-align: center;
        border-radius: 15px 15px 0px 0px;

    }

    .main-form {
        width: 800px;
        margin: auto;
        background-color: rgb(0, 0, 0, 0.7);
        padding-left: 50px;
        padding-right: 50px;
        padding-bottom: 20px;
        color: #FFFFFF;
    }
</style>


<head>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">

    <!-- Bootstrap CSS -->
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.0.0-beta3/dist/css/bootstrap.min.css" rel="stylesheet"
        integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">

    <title>Youtube Subtitle Downloader</title>
</head>

<body>

    <div class='regform mt-3'>
        <h1>Youtube Subtitle Downloader</h1>
    </div>

    <form action='/downloadsubs' class='main-form' method="POST">

        <div class='text-center'>
            <label> Paste Youtube Video URL</label>
            <input type="text" id="yturl" name='yturl' style="margin-top:10px;margin-bottom:10px;width: 700px;">
            <button type='submit' class='btn btn-outline-success' style="margin-top:10px;margin-bottom:10px;width: 700px;"> Download Subtitles
            </button>
        </div>

    </form>

    {% if url %}
    <div class="text-center">
        <h3>PDF Downloaded in your Folder as subtitle.pdf</h3>
        <a href='{{ url }}'><h2>Download Subtitles XML File</h2></a>
    </div>
    
    <div class="text-center">
        <p>{{ l }}</p>
    </div>
    {% endif %}

</body>

</html>