public static bool IsDataHTML(BinaryData fileData)
{
byte[] byteArray = new byte[4];
using (Stream str = fileData.AsStream())
{
str.Read(byteArray, 0, 4);
Encoding encoding = FindEncoding(ref byteArray);
string dataString = fileData.AsString(10240, encoding).ToLowerInvariant();
// Trim off byte order marks from the beginning of the string
dataString = dataString.TrimStart(new char[] { '\xFEFF', '\xFFFE' });
return IsStringHTML(dataString);
}
}
public static bool IsRtfFile(BinaryData data)
{
if (data.Length <= 5)
{
return false;
}
try
{
string headerstring = data.AsString(5, Encoding.UTF8);
return headerstring.CompareTo(@"{\rtf") == 0;
}
catch (Exception)
{
return false;
}
}
bool IsPdfFileWithHtmlTags(BinaryData binaryData)
{
var content = binaryData.AsString(1024, Encoding.ASCII).ToLower();
// Find <html>...</html>%PDF-1.4
// Expect file content to start with html open tag
// Expect pdf identifier to follow the html close tag
return (content.StartsWith("<html>") && content.Contains("</html>%pdf"));
}
private static string DataAsString(BinaryData binaryData, Encoding encoding)
{
if (null == binaryData)
return string.Empty;
return binaryData.AsString(16, encoding);
}