I want to restrict the fileupload to only accept .jpg and .png files, and to restrict the filesize

Question

I want to restrict the file size and file type on the profile picture. I want to allow only .jpg and .png pictures, and i also want to only allow a maximum file size of for example 1 megabyte. Under you see my code for uploading a file with no restrictions. I am using base64. I need to check file type and file size before the picture is uploaded but I really don't know how and where. If you need to see more of my code please let me know. Thank you very much.

    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> ChangePic(IndexViewModel model)
    {
        if (ModelState.IsValid)
        {
            var user = await _userManager.FindByIdAsync(User.GetUserId());

            var breader = new BinaryReader(model.ProfilePic.OpenReadStream());

            var byteImage = breader.ReadBytes((int)breader.BaseStream.Length);

            user.ProfilePic = byteImage;

            var result = await _userManager.UpdateAsync(user);
            if (result.Succeeded)
            {
                // For more information on how to enable account confirmation and password reset please visit http://go.microsoft.com/fwlink/?LinkID=532713
                // Send an email with this link
                //var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
                //var callbackUrl = Url.Action("ConfirmEmail", "Account", new { userId = user.Id, code = code }, protocol: HttpContext.Request.Scheme);
                //await _emailSender.SendEmailAsync(model.Email, "Confirm your account",
                //    "Please confirm your account by clicking this link: <a href=\"" + callbackUrl + "\">link</a>");
                await _signInManager.SignInAsync(user, isPersistent: false);
                _logger.LogInformation(3, "Profile info updated");
                return RedirectToAction(nameof(ManageController.Index), "Manage");
            }
            AddErrors(result);

        }

        // If we got this far, something failed, redisplay form
        return View(model);
    }

You can use validation attributes so that you get both client and server side validation - refer [this example of a FileTypeAttribute](http://stackoverflow.com/questions/33414158/checking-image-mime-size-etc-in-mvc/33426397#33426397) (and includes a link to a `FileSizeAttribute`) — , Apr 28 '16 at 08:59

score 1 · Accepted Answer · answered Apr 28 '16 at 09:04

You could add the following validation. That way it wont affect your existing action code.

public class IndexViewModel : IValidatableObject
{
    public HttpPostedFileBase ProfilePic { get; set; }

    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
    {

        if (ProfilePic.ContentType != "image/png" && ProfilePic.ContentType != "image/jpeg")
        {
            yield return new ValidationResult("Application only supports PNG or JPEG image types");
        }

        if (ProfilePic.ContentLength > 1000000)
        {
            yield return new ValidationResult("File size must not exceed 1MB");
        }

    }
}

Hope this helps!

Much appreciated! Thank you very much @heymega :) – Daniel Møller-Stray Apr 28 '16 at 12:03 — Daniel Møller-Stray, Apr 28 '16 at 12:03
No problem and welcome to SO. – heymega Apr 28 '16 at 15:02 — heymega, Apr 28 '16 at 15:02

score 0 · Answer 2 · edited May 23 '17 at 12:07

0

For the FileSize u could check something like this:

int maxUploadSize = 1000000 
if((int)breader.BaseStream.Length < maxUploadSize){
//upload it
}

To check the ImageType have a look at: https://stackoverflow.com/a/55876/4992212

The Link actually tells, that the initial bytes of an image are set to a particular value, so you can check the initial bytes and compare them with the image types you want to have.

edited May 23 '17 at 12:07

Community

1
1

answered Apr 28 '16 at 09:04

Tobias Theel

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Thank you @Tobias Theel. I've used this for file size! :) – Daniel Møller-Stray Apr 28 '16 at 12:04

I want to restrict the fileupload to only accept .jpg and .png files, and to restrict the filesize

2 Answers2