Code Review Feedback on Adding Pagination Functionality in ASP.NET Core Web API
I'm upgrading from an older version and I'm collaborating on a project where Code review revealed that the pagination for our ASP.NET Core Web API endpoint is not efficiently implemented... I've been tasked with enhancing the API to handle large datasets without slowing down performance. Currently, the API retrieves all records from the database, which causes significant latency when the data grows. Here's the existing code for the endpoint: ```csharp [HttpGet] public async Task<IActionResult> GetItems() { var items = await _context.Items.ToListAsync(); return Ok(items); } ``` The goal is to modify this to implement pagination, allowing clients to specify `pageNumber` and `pageSize` parameters. I attempted using LINQ's `Skip` and `Take` methods, which seemed like a straightforward approach. Here’s my revised code: ```csharp [HttpGet] public async Task<IActionResult> GetItems(int pageNumber = 1, int pageSize = 10) { var totalItems = await _context.Items.CountAsync(); var items = await _context.Items .Skip((pageNumber - 1) * pageSize) .Take(pageSize) .ToListAsync(); var result = new { TotalItems = totalItems, PageNumber = pageNumber, PageSize = pageSize, Items = items }; return Ok(result); } ``` While this seems to work, my peers pointed out that I might need to handle edge cases, like what happens when an invalid `pageNumber` is provided. I added checks but still received mixed feedback. Also, I noticed that if `pageNumber` is too large, it returns an empty array, which doesn’t seem user-friendly. Should I implement a mechanism to return the last available page instead? I've also read about using `IQueryable` for better performance, but not sure how to effectively integrate that here. Would appreciate insights on best practices for handling these cases and any improvements that can be made to the current implementation. What adjustments should I consider for edge cases, and how can I enhance the overall structure of this endpoint? The stack includes C# and several other technologies. The stack includes C# and several other technologies.