Esempio n. 1
0
    /// <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);
    }