Redirect upon submit button linking to send_file

[Jamesunsworth]

Hi guys,

I've been researching and coding til my fingers have fallen off on this one!

I'm currently building a youtube video downloader simply to embed python into my brain by doing small projects.

So my current setup (just a brief overview).

1. index page to enter youtube URL - hit the submit button which then executes a function to download youtube video to folder on server, follwed by a return redirect to goto 'conversion complete' page.

2. Arrive at the 'conversion complete' page where you are shown a download button. Click this and it downloads the file but stays on that page with the download button still there.

button for step 2 is...

<a href='download' type='button'><button class='btn btn-default'>Download!</button></a>

My 'download' page doesn't actually show, it simply executes a send_file function to grab the file from step 1 off the server and give to user to download in browser.

So, ultimately, everythings works as I want it to, except that I want to redirect the page after clicking the download button (just to show a page saying download complete, or goto the index page, whatever, location isn't important, it's the fact it won't actually redirect anywhere), however I have seen many people have issues with a redirect following a send file and hope you guys can help!


Popped my python code below incase needed. Feel free to tell me if there's a better way to do something i'm doing. (I'm aware there maybe some imports at the top being used that aren't needed, I'll clean those up later along with removing get/post requests on routes that aren't needed - i put them there for now just to ensure that doesn't trip me up)

Really appreciate any help here! I've come this far without asking for help, but just need a little advice to get over the finish line!

###################################
####### Youtube Downloader ########
###################################

from flask import Flask, render_template, redirect, url_for, session, request, flash, send_file
from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField, BooleanField
from pytube import YouTube
import os
import random, string
import re

app = Flask(__name__)

app.config['SECRET_KEY'] = 'mysecretkey'
session_id = ''.join(random.choices(string.ascii_letters + string.digits, k=6))

######################################
############## Forms #################
######################################

class url_form(FlaskForm):
    link = StringField('Enter link of YouTube video you would like to convert...')
    audio = BooleanField('Audio Only')
    submit = SubmitField('Convert')

######################################
############## Functions##############
######################################

def download_video(link, just_audio):

    yt = YouTube(link)
    download_path = 'conversions/'
    #global myvar
    if just_audio == True:

        stream = yt.streams.filter(only_audio=True).first()
        tag = 'video'


    else:

        stream = yt.streams.filter(adaptive=True).first()
        tag = 'audio only'

    download_video.name = yt.title
    download_video.cleanString = re.sub('[^a-zA-Z0-9 \n\.]', '', download_video.name)
    download_video.thumbnail = yt.thumbnail_url
    download_video.path = stream.download(filename = download_video.cleanString, output_path = download_path)

    return



######################################
############## MAIN ##################
######################################

@app.route('/', methods=['GET', 'POST'])
def index():
    result = False
    form = url_form()


    if form.validate_on_submit():

        session['link'] = form.link.data

        if form.audio.data:
            just_audio = True
        else:
            just_audio = False

        session['just_audio'] = just_audio
        link = session.get('link')
        just_audio = session.get('just_audio')
        download_video(link, just_audio)
        #download_video(link, just_audio)
        #return send_file(download_video.path, attachment_filename=download_video.cleanString + '.mp4', as_attachment=True) # CURRENTLY GETTING FROM ROOT FOLDER!
        return redirect(url_for('conversion_complete'))
    return render_template('index.html', form=form, result=result) # URL Variable here relates to decorator variable


@app.route('/conversion_complete', methods=['GET', 'POST'])
def conversion_complete():


    return render_template('conversion_complete.html') # URL Variable here relates to decorator variable


@app.route('/download/', methods=['GET'])
def download():

    return send_file(download_video.path, attachment_filename=download_video.cleanString + '.mp4', as_attachment=True) # CURRENTLY GETTING FROM ROOT FOLDER!

    return render_template('result.html')

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