Question

我想限制个人资料图片上的文件大小和文件类型。我想只允许.jpg和.png图片，我也想只允许最大文件大小，例如1兆字节。在你看到我的代码上传文件没有任何限制。我正在使用base64。我需要在图片上传之前检查文件类型和文件大小，但我真的不知道如何以及在何处。如果您需要查看更多我的代码，请告诉我。非常感谢你。

    [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);
    }

Answer 1

您可以添加以下验证。这样它就不会影响您现有的操作代码。

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");
        }

    }
}

希望这有帮助！

Answer 2

对于FileSize，您可以检查以下内容：

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

要检查ImageType，请查看：https://stackoverflow.com/a/55876/4992212

链接实际上告诉我，图像的初始字节设置为特定值，因此您可以检查初始字节并将它们与您想要的图像类型进行比较。

我想限制fileupload只接受.jpg和.png文件，并限制文件大小

2 个答案: