Upload and Read Excel File in Flask

Last Updated : 10 Jan, 2023

In this article, we will look at how to read an Excel file in Flask. We will use the Python Pandas library to parse this excel data as HTML to make our job easier. Pandas additionally depend on openpyxl library to process Excel file formats. Before we begin, make sure that you have installed both Flask and Pandas libraries along with the openpyxl dependency.

Required Module:

pip install flask==2.2.2
pip install pandas==1.4.2
pip install openpyxl==3.0.10

File Structure

Please make sure that you name the HTML file as ‘upload-excel.html’ and place it in the ‘templates’ folder within the root directory of the application.

HTML Template

Create the HTML template which will render the user interface to view the Browse and Upload options for the file. We have allowed uploading of MS Excel and Open XML formats only through the accepted attribute of the input tag.

HTML

<!DOCTYPE html>
<html lang="en">
 
<head>
    <title>Upload/View Excel</title>
</head>
 
<body>
    <h1>Upload Excel File (.xlsx)</h1>
    <form action="{{ url_for('view') }}" method="post" enctype="multipart/form-data">
        <input type="file" name="file"
            accept="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel">
        <input type="submit" value="Upload">
    </form>
</body>
 
</html>

Upload and Read Excel File in Flask

Step 1: Upload Excel File in Flask

Import the required module

Python3

# Importing required functions
import pandas from flask import Flask, render_template, request

Step 2: Read Excel File in Flask

This Function returns the index page to upload the Excel file.

Python3

# Root endpoint
@app.get('/')
def upload():
    return render_template('upload-excel.html')

Step 3:

Here, we have created the Flask App which will contain two endpoints. One endpoint will handle a GET request from the root URL. This will return the HTML template which contains the option to upload files. The other endpoint is ‘/view’ which handles POST requests. This will read the upload file and return the HTML snippet to view the uploaded Excel in tabular format in the browser window. Also, the file will save in your local directory using the function save().

Python3

# Importing required functions
import pandas
from flask import Flask, render_template, request
from fileinput import filename
 
# Flask constructor
app = Flask(__name__)
 
# Root endpoint
@app.get('/')
def upload():
    return render_template('upload-excel.html')
 
 
@app.post('/view')
def view():
 
    # Read the File using Flask request
    file = request.files['file']
    # save file in local directory
    file.save(file.filename)
 
    # Parse the data as a Pandas DataFrame type
    data = pandas.read_excel(file)
 
    # Return HTML snippet that will render the table
    return data.to_html()
 
 
# Main Driver Function
if __name__ == '__main__':
    # Run the application on the local development server
    app.run(debug=True)