Uploading Multiple Files in Python Without a Framework: A Step-by-Step Guide

Posted on by R SOTH
Estimated read time 3 min read

Introduction

Uploading multiple files is a common requirement in web applications. In this article, we’ll explore how to achieve this in Python without using a web framework. We’ll build a simple script using the standard library’s http.server module to handle file uploads.

1. Understanding the Basics:

  • Before diving into code, it’s crucial to understand the basics of file uploads over HTTP. When a client uploads files, the server receives the files as part of the HTTP request, typically using the multipart/form-data encoding.

2. Creating the HTML Form:

  • Start by creating a basic HTML form that allows users to select and upload multiple files. The form should use the enctype="multipart/form-data" attribute to enable file uploads.
   <!DOCTYPE html>
   <html lang="en">
   <head>
       <meta charset="UTF-8">
       <title>File Upload</title>
   </head>
   <body>
       <form action="http://localhost:8000/upload" method="post" enctype="multipart/form-data">
           <input type="file" name="files" multiple>
           <input type="submit" value="Upload">
       </form>
   </body>
   </html>

3. Handling File Uploads in Python:

  • Use the http.server module, which is part of the Python standard library, to handle file uploads. Create a custom handler by subclassing http.server.BaseHTTPRequestHandler.
   from http.server import HTTPServer, BaseHTTPRequestHandler

   class FileUploadHandler(BaseHTTPRequestHandler):
       def do_POST(self):
           content_type, _ = cgi.parse_header(self.headers['content-type'])
           if content_type == 'multipart/form-data':
               form_data = cgi.FieldStorage(
                   fp=self.rfile,
                   headers=self.headers,
                   environ={'REQUEST_METHOD': 'POST'}
               )

               files = form_data.getlist('files')
               for file in files:
                   # Save each file to the server or process as needed
                   with open(file.filename, 'wb') as f:
                       f.write(file.file.read())

               self.send_response(200)
               self.end_headers()
               self.wfile.write(b'Successfully uploaded files')
           else:
               self.send_response(400)
               self.end_headers()
               self.wfile.write(b'Invalid content type')

   def run(server_class=HTTPServer, handler_class=FileUploadHandler, port=8000):
       server_address = ('', port)
       httpd = server_class(server_address, handler_class)
       print(f'Starting server on port {port}')
       httpd.serve_forever()

   if __name__ == '__main__':
       run()

4. Running the Server:

  • Save the Python script, let’s call it file_upload.py, and run it in your terminal. This will start a simple server at http://localhost:8000.
   python file_upload.py

5. Testing the File Upload:

  • Open a web browser and navigate to http://localhost:8000. You should see the file upload form. Select multiple files and click the “Upload” button. The server should respond with a success message.

6. Enhancements and Considerations:

  • Depending on your use case, you may want to enhance the script by adding error handling, implementing file type checks, and securing the upload endpoint.

Conclusion:

  • Uploading multiple files without a web framework in Python is achievable using the standard library’s http.server module. While this approach is suitable for small projects or learning purposes, for production applications, consider using a web framework for more features, security, and scalability.
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