/// <summary>
/// Validate if PostedFile is an Image and Provide Content
/// </summary>
/// <param name="postedFile"></param>
/// <param name="fileData"></param>
/// <param name="fileName"></param>
/// <param name="fileType"></param>
/// <param name="fileImage"></param>
/// <returns>Posted File Information</returns>
public static bool IsImage(this HttpPostedFile postedFile, out byte[] fileData, out string fileName, out string fileType, out Image fileImage, out string exception)
{
// outs are defined at validation
fileImage = null;
fileData = null;
fileName = null;
fileType = null;
//-------------------------------------------
// Check the image mime types
//-------------------------------------------
if (!string.Equals(postedFile.ContentType, "image/jpg", StringComparison.OrdinalIgnoreCase) &&
!string.Equals(postedFile.ContentType, "image/jpeg", StringComparison.OrdinalIgnoreCase) &&
!string.Equals(postedFile.ContentType, "image/png", StringComparison.OrdinalIgnoreCase))
{
exception = "Ungültiger Dateityp";
return(false);
}
//-------------------------------------------
// Check the image extension
//-------------------------------------------
var postedFileExtension = Path.GetExtension(postedFile.FileName);
if (!string.Equals(postedFileExtension, ".jpg", StringComparison.OrdinalIgnoreCase) &&
!string.Equals(postedFileExtension, ".png", StringComparison.OrdinalIgnoreCase) &&
!string.Equals(postedFileExtension, ".jpeg", StringComparison.OrdinalIgnoreCase))
{
exception = "Ungültiger Dateityp";
return(false);
}
else
{
fileName = postedFile.FileName.Replace(postedFileExtension, "");
fileType = postedFileExtension;
}
//-------------------------------------------
// Attempt to read the file and check the first bytes
//-------------------------------------------
try
{
if (!postedFile.InputStream.CanRead)
{
exception = "Datei konnte nicht gelesen werden";
return(false);
}
//------------------------------------------
// Check whether the image size exceeding the limit or not
//------------------------------------------
if (postedFile.ContentLength < 512)
{
exception = "Datei zu klein, ungültige Datei?";
return(false);
}
fileData = postedFile.LoadUploadedFile();
string content = System.Text.Encoding.UTF8.GetString(fileData);
if (Regex.IsMatch(content, @"<script|<html|<head|<title|<body|<pre|<table|<a\s+href|<img|<plaintext|<cross\-domain\-policy",
RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Multiline))
{
exception = "Ungültige Datei.";
return(false);
}
}
catch (Exception)
{
exception = "Unbehandelter Fehler";
return(false);
}
//-------------------------------------------
// Try to instantiate new Bitmap, if .NET will throw exception
// we can assume that it's not a valid image
//-------------------------------------------
try
{
fileImage = fileData.StreamToImage();
var temp = RotateImageByExifOrientationData(fileImage, true);
// We don't need to reassign this when the Image wasn't being rotated anyways.
if (RotateFlipType.RotateNoneFlipNone != temp)
{
fileData = ImageToByteArray(fileImage);
}
}
catch (Exception e1)
{
exception = "Datei konnte nicht gelesen werden";
return(false);
}
finally
{
postedFile.InputStream.Position = 0;
}
exception = null;
return(true);
}
