Python Flask Multiple Files Upload Example - Roy Tutorials - The first knowledge sharing application in Vietnam

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Introduction

The tutorial, Python flask multiple files upload example, will show you how to upload multiple files using Python 3 and Flask technologies. You may also find useful example on file upload on different technologies.

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Prerequisites

Have Python installed in Windows (or Unix)
Pyhton version and Packages
I am using Python 3.6.6 version

Example with Source Code

Please go through the following steps in order to implement Python flask multiple files upload example.

Step 1. Create the below app.py script(py is the extension to indicate Python script) where we import the flask module. Notice how we create flask instance. Here we need to assign secret key otherwise flash will not work in Python.

In the below script we import the required module – Flask. If you do not have this module then install it.

Here we have also specified the file upload folder and maximum size of the file to be uploaded as 16MB.

from flask import FlaskUPLOAD_FOLDER = 'D:/uploads'app = Flask(__name__)app.secret_key = "secret key"app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDERapp.config['MAX_CONTENT_LENGTH'] = 16 * 1024 * 1024

Step 2. Next we need main.py script. This script is the perfect instance of Python flask file upload example. It defines all required URIs for performing file upload operations.

We have used upload.html page for uploading file to the desired directory.

We show success message on successful file upload.

import os#import magicimport urllib.requestfrom app import appfrom flask import Flask, flash, request, redirect, render_templatefrom werkzeug.utils import secure_filenameALLOWED_EXTENSIONS = set(['txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'])def allowed_file(filename):	return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS	@app.route('/')def upload_form():	return render_template('upload.html')@app.route('/', methods=['POST'])def upload_file():	if request.method == 'POST':        # check if the post request has the files part		if 'files[]' not in request.files:			flash('No file part')			return redirect(request.url)		files = request.files.getlist('files[]')		for file in files:			if file and allowed_file(file.filename):				filename = secure_filename(file.filename)				file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))		flash('File(s) successfully uploaded')		return redirect('/')if __name__ == "__main__":    app.run()

Step 3. Now we need template page for uploading file. This is upload.html page kept under subdirectory – templates. You can use this page for uploading single or multiple files. If you want to upload multiple files then you need to hold CTRL key and select files.

<!doctype html><title>Python Flask Multiple Files Upload Example</title><h2>Select file(s) to upload</h2><p>	{% with messages = get_flashed_messages() %}	  {% if messages %}		<ul class=flashes>		{% for message in messages %}		  <li>{{ message }}</li>		{% endfor %}		</ul>	  {% endif %}	{% endwith %}</p><form method="post" action="/" enctype="multipart/form-data">    <dl>		<p>			<input type="file" name="files[]" multiple="true" autocomplete="off" required>		</p>    </dl>    <p>		<input type="submit" value="Submit">	</p></form>