This pull request addresses issue Cloud-CV#4414 by implementing file format validation for submissions to ensure that only accepted file formats are allowed. The changes include both client-side and server-side validations.

Changes Made:

1. Client-Side Validation:

   • Implemented file format validation in JavaScript to ensure that only accepted file formats (e.g., CSV) are allowed for submission.
   • Added an event listener to the file input element to validate the file format before submission.

2. Server-Side Validation:

   • Added file format validation in Django to ensure that the validation is not bypassed.
   • Implemented a validate_file_format function to check the file content type and raise a ValidationError if the format is not accepted.

3. Error Messaging:

   • Displayed an error message to the user if the file format is not accepted, indicating the accepted file formats for the challenge.

Files Modified:

• Client-Side:

  • frontend/src/js/controllers/SubmissionFilesCtrl.js
  • frontend/src/views/web/challenge/submission.html

• Server-Side:

  • apps/challenges/views.py

How to Test:

1. Client-Side:

   • Navigate to the submission page.
   • Try uploading a file with an invalid format (e.g., .txt).
   • Verify that an error message is displayed and the file is not submitted.

2. Server-Side:

   • Submit a file with an invalid format via the API.
   • Verify that the server responds with an appropriate error message.

Issue Reference:

Fixes Cloud-CV#4414