Read Csv on asp.net core endpoint

Question

I am trying to create an endpoint that accepts a CSV file but the data stream doesn't return any records.

This is my view model:

public class BulkUploadViewModel
{
    [Required]
    public IFormFile JobCsv { get; set; }
    [Required]
    public string UserId { get; set; }
}

And this is my endpoint:

[Route("BulkUpload")]
[HttpPost]
public async Task<IActionResult> BulkUpload(BulkUploadViewModel bulkUpload)
{
    if(!ModelState.IsValid)
    {
        return BadRequest();
    }

    List<BulkUploadDataModel> bulkList = new List<BulkUploadDataModel>();

    using (var memoryStream = new MemoryStream())
    {
        await bulkUpload.JobCsv.CopyToAsync(memoryStream);
        TextReader textReader = new StreamReader(memoryStream);

        var csv = new CsvReader(textReader);

        csv.Configuration.HasHeaderRecord = true;

        bulkList = csv.GetRecords<BulkUploadDataModel>().ToList();
    }

    return Ok(bulkList.Count());
}

I have also tried reading the CSV line by line but Csv.Read() returns false. I am not sure how to debug this.

I am generating the post with postman:

In the debugger I can see the file name and length value are populated correctly in bulkUpload.JobCsv so I assume my error is in how I am accessing the stream.

What did I do wrong?

Answer 1

You are just missing memoryStream.Position = 0 after
await bulkUpload.JobCsv.CopyToAsync(memoryStream);.

like this:

await bulkUpload.JobCsv.CopyToAsync(memoryStream);
memoryStream.Position = 0;
TextReader textReader = new StreamReader(memoryStream);