[Backend]: Add pagination, search, and filtering to the course listing API

[Jidnyasa-P]

Description

The /getallcourses endpoint currently returns every course from MongoDB in a single response.

As the course collection grows, this can increase response size, database load, and API latency.

Proposed solution

Add server-side query support for:

• page
• limit
• search
• category
• educator
• priceType
• sort

Example:

GET /api/user/getallcourses?page=1&limit=12&search=javascript&category=programming&sort=newest

The response should include:

{
  "success": true,
  "data": [],
  "pagination": {
    "page": 1,
    "limit": 12,
    "totalItems": 0,
    "totalPages": 0,
    "hasNextPage": false,
    "hasPreviousPage": false
  }
}

Validation requirements

• Default page to 1.
• Default limit to a reasonable value such as 12.
• Cap limit at 100.
• Reject or safely normalize negative and malformed values.
• Escape search input before constructing regular expressions.
• Preserve the existing endpoint path.
• Return an empty array rather than 404 when no courses match.

Acceptance criteria

• Pagination works correctly.
• Search supports course title and description.
• Category filtering works.
• Educator filtering works.
• Free and paid filtering works.
• Sorting works for newest, title, and enrollment count.
• Pagination metadata is returned.
• Oversized limits are capped.
• Existing consumers remain compatible.
• Backend tests cover filtering, sorting, and invalid query values.
• No frontend changes are required.

Suggested files

backend/controllers/userControllers.js
backend/routers/userRoutes.js
backend/utils/pagination.js
backend/tests/course-listing.test.js

[Jidnyasa-P]

/assign

[Jidnyasa-P]

@udaycodespace Kindly assign this issue to me under ECSOC26

[udaycodespace]

@Jidnyasa-P It’s been 4 days with no progress. Please try to complete it by the first half of Monday, so I can review it by Monday night.

In the PR, please include the relevant commands and their outputs, along with a snippet/screenshot of the UI changes, if applicable.