/// <summary>Validates the specified object.</summary>
/// <param name="value">The object to validate.</param>
/// <param name="validationContext">The <see cref="T:System.ComponentModel.DataAnnotations.ValidationContext" /> object that describes the context where the validation checks are performed. This parameter cannot be null.</param>
/// <exception cref="T:System.ComponentModel.DataAnnotations.ValidationException">Validation failed.</exception>
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
var postedFile = value as HttpPostedFileBase;
if (postedFile == null)
{
// No posted file to validate
return(ValidationResult.Success);
}
// Validate posted file size
if (Size > 0 && postedFile.ContentLength > Size)
{
return(new ValidationResult(string.Format(CultureInfo.CurrentCulture, DataAnnotationsResources.FileAttribute_InvalidSize, validationContext.DisplayName, GetAllowedFileSizeDescription(Size))));
}
byte[] postedBytes = null;
// Get file model of posted file by matching against posted file extension
var postedExtension = postedFile.FileName.Split('.').LastOrDefault();
if (postedExtension == null)
{
return(new ValidationResult(string.Format(CultureInfo.CurrentCulture, DataAnnotationsResources.FileAttribute_InvalidExtension, validationContext.DisplayName, GetAllowedFileExtensionsDescription())));
}
// Get file model of posted file by matching against posted file extension
var postedFileModel = FileModels.FirstOrDefault(m => m.Extensions.Contains(postedExtension.ToLower()));
// Invalid posted file if there is no matching file model or it is not an allowed file type
if (postedFileModel == null || !FileTypes.Contains(postedFileModel.FileType))
{
return(new ValidationResult(string.Format(CultureInfo.CurrentCulture, DataAnnotationsResources.FileAttribute_InvalidType, validationContext.DisplayName, GetAllowedFileExtensionsDescription())));
}
// Check config to see if file signature check should be skipped
bool skip;
if ((postedFileModel.FileType != FileType.Txt) && !(ConfigurationManager.AppSettings["SkipFileSignatureCheck"] != null && bool.TryParse(ConfigurationManager.AppSettings.Get("SkipFileSignatureCheck"), out skip) && skip))
{
// Get copy of bytes
postedBytes = postedFile.GetBytes();
// Check posted file data has a valid signature for its file type
if (!postedFileModel.ValidSignature(postedBytes))
{
return(new ValidationResult(string.Format(CultureInfo.CurrentCulture, DataAnnotationsResources.FileAttribute_InvalidSignature, validationContext.DisplayName, GetAllowedFileExtensionsDescription())));
}
}
// RTF specific validation
if (postedFileModel.FileType == FileType.Rtf)
{
postedBytes = postedBytes ?? postedFile.GetBytes();
var text = new UTF8Encoding().GetString(postedBytes, 0, postedBytes.Length);
if (!string.IsNullOrEmpty(text))
{
text = text.ToLower();
if (text.Contains(string.Format("{0}{{", RtfImageTag)) || text.Contains(string.Format("{0}\\", RtfImageTag)) || text.Contains(string.Format("{0}{{", RtfDrawingTag)) || text.Contains(string.Format("{0}\\", RtfDrawingTag)))
{
return(new ValidationResult(string.Format(DataAnnotationsResources.FileAttribute_InvalidRtfImage, validationContext.DisplayName)));
}
if (text.Contains(string.Format("{0}{{", RtfObjectTag)) || text.Contains(string.Format("{0}\\", RtfObjectTag)) || text.Contains(string.Format("{0}{{", RtfMacObjectTag)) || text.Contains(string.Format("{0}\\", RtfMacObjectTag)))
{
return(new ValidationResult(string.Format(DataAnnotationsResources.FileAttribute_InvalidRtfObject, validationContext.DisplayName)));
}
var blueWordResult = new BlueWordAttribute().ValidateBlueWord(validationContext.DisplayName, text);
if (blueWordResult != ValidationResult.Success)
{
return(blueWordResult);
}
}
}
// Validate compressed file size
if (CompressedSize > 0)
{
var compressedBytes = (postedBytes ?? postedFile.GetBytes()).Compress();
if (compressedBytes != null && compressedBytes.Length > CompressedSize)
{
return(new ValidationResult(string.Format(CultureInfo.CurrentCulture, DataAnnotationsResources.FileAttribute_InvalidCompressedSize, validationContext.DisplayName, GetAllowedFileSizeDescription(CompressedSize))));
}
}
return(ValidationResult.Success);
}