How to Upload files to a Directory with Flask and Python?

How to Upload files to a Directory with Flask and Python?

In this tutorial, we will explore how to upload files to a directory using Flask, a popular Python web framework. Flask provides a lightweight and flexible way to handle file uploads, allowing you to build web applications that accept and store user-submitted files.

We will walk through the step-by-step process of creating a Flask application that includes a file upload feature. You will learn how to set up the necessary routes, handle file uploads, and save the uploaded files to a specific directory on your server.

If you are a beginner, this tutorial will provide you with the knowledge and skills to implement file uploading functionality in your Flask applications. So let's get started and learn how to upload files to a directory with pure Flask!

1- Setup Flask!

To set up Flask using pip, follow these steps:

  1. Open your command-line interface (such as Terminal or Command Prompt).
  2. Make sure you have Python and pip installed on your system.
  3. Wait for the installation to finish. Flask and its dependencies will be downloaded and installed.
  4. Once the installation is complete, you can start using Flask to develop web applications.

Run the following command to install Flask:

pip install flask

Note: It's recommended to set up a virtual environment before installing Flask to keep your project dependencies isolated. You can use tools like virtualenv or venv to create a virtual environment.

2- Create your App file

from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello():
    return 'Hello, World!'

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

3- Create the Upload Form Template

Create your upload form in ./templates/index.html.

<!doctype html>
<html>
  <head>
    <title>FLASK File Uploads</title>
  </head>
  <body>
    <h1>Upload your file</h1>
    <form method="POST" action="" enctype="multipart/form-data">
      <p><input type="file" name="file"></p>
      <p><input type="submit" value="Submit"></p>
    </form>
  </body>
</html>

4- Perform the File Upload Action

from flask import Flask, render_template, request, redirect, url_for
import os
from os.path import join, dirname, realpath





app = Flask(__name__)

# enable debugging mode
app.config["DEBUG"] = True

# Upload folder
UPLOAD_FOLDER = 'files'
app.config['UPLOAD_FOLDER'] =  UPLOAD_FOLDER





# Root URL
@app.route('/')
def index():
     # Set The upload HTML template '\templates\index.html'

    return render_template('index.html')


# Get the uploaded files
@app.route("/", methods=['POST'])
def uploadFiles():
      # get the uploaded file
      uploaded_file = request.files['file']
      if uploaded_file.filename != '':
           file_path = os.path.join(app.config['UPLOAD_FOLDER'], uploaded_file.filename)
          # set the file path
           uploaded_file.save(file_path)
          # save the file
      return redirect(url_for('index'))




if (__name__ == "__main__"):
     app.run(port = 5000)

5- List the uploaded files in the upload Directory

To list the uploaded files from the upload directory, we will edit our main Root Route function:

# Root URL
@app.route('/')
def index():
    files = os.listdir('./files')    
    return render_template('index.html', files=files)

Then we will display the files in the HTML template:

<!doctype html>
<html>
  <head>
    <title>FLASK File Uploads</title>
  </head>
  <body>
    <h1>Upload your file</h1>
    <form method="POST" action="" enctype="multipart/form-data">
      <p><input type="file" name="file"></p>
      <p><input type="submit" value="Submit"></p>
    </form>
    <!--uploded files-->
    <div>      
      <ul>        
        {% for file in files %}
            <li>{{ file }}</li>
        {% endfor %}
        </ul>
    </div>  
    <!--/uploded files-->
  </body>
</html>

6- Bonus: Access from the local network

If you want to access your Flask development server and test your app within your local network, edit your host setting:

if __name__ == '__main__':
    # run app in debug mode on port 5000
    app.run(debug=True, port=5055, host='0.0.0.0')

Now you know how to perform simple file uploads using Flask.

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