Python 3 Flask Project to Rotate PDF Document By Any Angle Using PyPDF2 Library in Browser Using HTML5

Welcome folks today in this blog post we will be rotating pdf document by any angle in any direction in browser using pypdf2 library in browser using flask. 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

pip install pypdf2

And after that you need to make an app.py file and copy paste the following code

app.py

from flask import Flask, render_template, request, send_file
from werkzeug.utils import secure_filename
import os
import PyPDF2

app = Flask(__name__)

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

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

from flask import Flask, render_template, request, send_file

from werkzeug.utils import secure_filename

import os

import PyPDF2

app = Flask(__name__)

@app.route('/')

def index():

return render_template('index.html')

if __name__ == '__main__':

app.run()

As you can see we are importing the flask library and then we are also importing the pypdf2 library at the top to rotate pdf document using any angle. And then we have started the flask app at the port number 5000. And then we have initialized the / route where we are loading the index.html template file. For this you need to create the templates folder and inside it you need to create the index.html file and copy paste the following code

templates/index.html

<form method="post" action="/rotate" enctype="multipart/form-data">
    <input type="file" name="file">
    <label for="angle">Angle:</label><br>
    <input type="text" id="angle" name="angle"><br>
    <input type="submit" value="Rotate">
  </form>

<label for="angle">Angle:</label><br>

</form>

As you can see we have the simple input field where we allow the user to select pdf files and then we have the input field where we allow the user to enter any angle to which we need to rotate the pdf document and then we have the submit button to rotate the pdf document. Now if you start the flask app using the below command

python app.py

Now we need to write the post request to actually rotate pdf files which is selected by the user using the input field as shown below

@app.route('/rotate', methods=['POST'])
def rotate():
    # Get the uploaded file and the rotation angle
    file = request.files['file']
    angle = request.form['angle']
    filename = secure_filename(file.filename)

    # Save the file to a temporary directory
    file.save(os.path.join('/tmp', filename))

    # Open the PDF and rotate each page
    with open(os.path.join('/tmp', filename), 'rb') as f:
        pdf = PyPDF2.PdfFileReader(f)
        output = PyPDF2.PdfFileWriter()
        for i in range(pdf.getNumPages()):
            page = pdf.getPage(i)
            page.rotateClockwise(float(angle))
            output.addPage(page)
        with open(os.path.join('/tmp', 'rotated.pdf'), 'wb') as f:
            output.write(f)

    # Return a link to download the rotated PDF
    return '<a href="/download">Download Rotated PDF</a>'

@app.route('/rotate', methods=['POST'])

def rotate():

# Get the uploaded file and the rotation angle

file = request.files['file']

angle = request.form['angle']

filename = secure_filename(file.filename)

# Save the file to a temporary directory

file.save(os.path.join('/tmp', filename))

# Open the PDF and rotate each page

with open(os.path.join('/tmp', filename), 'rb') as f:

pdf = PyPDF2.PdfFileReader(f)

output = PyPDF2.PdfFileWriter()

for i in range(pdf.getNumPages()):

page = pdf.getPage(i)

page.rotateClockwise(float(angle))

output.addPage(page)

with open(os.path.join('/tmp', 'rotated.pdf'), 'wb') as f:

output.write(f)

# Return a link to download the rotated PDF

return '<a href="/download">Download Rotated PDF</a>'

As you can see inside the above function we are first of all comparing the request if it’s equal to POST and then we are using the request module to get access to all the files selected by the user. And then we are initializing the PDFFileReader() method to read the content of the pdf document which is selected and then we are using the for loop to rotate the pages using custom angle and then we are using the rotateClockwise() method to rotate the pdf document and we are passing the angle as an argument. And then we are allowing the user to download the pdf document as an attachment inside the browser.

Now we need to write the download request inside the app.py to allow the user to download the rotated pdf document pages as separated pdf documents as shown below

@app.route('/download')
def download():
    # Send the rotated PDF as a response
    return send_file('/tmp/rotated.pdf', as_attachment=True)

@app.route('/download')

def download():

# Send the rotated PDF as a response

return send_file('/tmp/rotated.pdf', as_attachment=True)

Full Source Code