Python 3 Flask to Download File as an Attachment in Browser Using HTML5

Welcome folks today in this blog post we will downloading file as an attachment in browser using html5 in browser. All the full source code of the application is shown below.

Get Started

In order to get started you need to install the below libraries using the pip command as shown below

pip install flask

Now we will see the below directory structure of the flask app as shown below

And now you need to make an app.py file and copy paste the below code

app.py

from flask import Flask,render_template

app = Flask(__name__)

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


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

from flask import Flask,render_template

app = Flask(__name__)

@app.route('/')

def index():

return render_template('index.html')

if __name__ == "__main__":

app.run(debug=True)

As you can see we are importing the flask library and starting the app at port number 5000. And also we are rendering the index.html template file whenever we go to the / route. We are using the render_template() for this purpose. And now we need to make this template inside the templates folder

templates/index.html

<h2>Download the File as an Attachment</h2>

<a href="{{url_for('download_file')}}">Download File</a>

<h2>Download the File as an Attachment</h2>

<a href="{{url_for('download_file')}}">Download File</a>

As you can see we are simply have an anchor element where we are allowing the user to download the file as an attachment. Now we have attached the url_for directive to the href attribute. Now we need to create the download_file method as shown below

app.py

from flask import Flask,render_template,send_file

app = Flask(__name__)

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

@app.route('/download_file')
def download_file():
    path = "image.png"
    return send_file(path,as_attachment=True)

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

from flask import Flask,render_template,send_file

app = Flask(__name__)

@app.route('/')

def index():

return render_template('index.html')

@app.route('/download_file')

def download_file():

path = "image.png"

return send_file(path,as_attachment=True)

if __name__ == "__main__":

app.run(debug=True)

As you can see we have defined another get route to download the file as an attachment and inside it we are importing the send_file() method of flask to download the file and then we are passing the path of the file to be downloaded and also providing the second boolean parameter as_attachment to True.