public static void ReuseConverter(ConverterReader converter, object newSource)
{
converter.Reuse(newSource);
}
/// <summary>
/// Invoked by Exchange when the entire message has been received.
/// </summary>
/// <param name="source">The source of this event.</param>
/// <param name="eodArgs">The arguments for this event.</param>
public void OnEndOfDataHandler(ReceiveMessageEventSource source, EndOfDataEventArgs eodArgs)
{
Debug.WriteLine("[BodyConversion] OnEndOfDataHandler is called");
// The purpose of this sample is to show how TextConverters can be used
// to update the body. This sample shows how to ensure that no active
// content, such as scripts, can pass through in a message body.
EmailMessage message = eodArgs.MailItem.Message;
Stream originalBodyContent = null;
Stream newBodyContent = null;
Encoding encoding;
string charsetName;
try
{
Body body = message.Body;
BodyFormat bodyFormat = body.BodyFormat;
if (!body.TryGetContentReadStream(out originalBodyContent))
{
// You cannot decode the body.
return;
}
if (BodyFormat.Text == bodyFormat)
{
// Plain text body. Add a disclaimer to this body.
charsetName = body.CharsetName;
if (null == charsetName ||
!Microsoft.Exchange.Data.Globalization.Charset.TryGetEncoding(charsetName, out encoding))
{
// Either no charset, or charset is not supported by the system.
return;
}
// Create and set up the TextToText conversion object.
TextToText textToTextConversion = new TextToText();
// Don't change the body code page.
textToTextConversion.InputEncoding = encoding;
// By default, the output code page is the same as the input code page.
// Add a disclaimer to indicate that the body is not being filtered.
textToTextConversion.HeaderFooterFormat = HeaderFooterFormat.Text;
textToTextConversion.Footer = "the plain text body is NOT being filtered";
// Open the stream to write updated content into.
newBodyContent = body.GetContentWriteStream();
// Do the conversion. This will replace the original text.
// with an updated version.
try
{
// The easiest way to do the conversion in one step is by using the Convert
// method. It creates the appropriate converter stream
// and copies from one stream to another.
textToTextConversion.Convert(originalBodyContent, newBodyContent);
}
catch (Microsoft.Exchange.Data.TextConverters.TextConvertersException)
{
// The conversion has failed.
}
}
else if (BodyFormat.Html == bodyFormat)
{
// The HTML body.
// Filter the original HTML to remove any scripts and other
// potentially unsafe content.
charsetName = body.CharsetName;
if (null == charsetName ||
!Microsoft.Exchange.Data.Globalization.Charset.TryGetEncoding(charsetName, out encoding))
{
// Either no charset, or charset is not supported by the system.
return;
}
// Create and set up the HtmlToHtml conversion object.
HtmlToHtml htmlToHtmlConversion = new HtmlToHtml();
// Don't change the body code page.
htmlToHtmlConversion.InputEncoding = encoding;
// By default, the output code page is the same as the input code page.
// Set up output HTML filtering. HTML filtering will ensure that
// no scripts or active content can pass through.
htmlToHtmlConversion.FilterHtml = true;
// Add a disclaimer to indicate that the body is being filtered.
htmlToHtmlConversion.HeaderFooterFormat = HeaderFooterFormat.Html;
htmlToHtmlConversion.Footer = "<p><font face=\"Arial\" size=\"+1\">the HTML body is being filtered</font></p>";
// Open the stream to write updated content into.
newBodyContent = body.GetContentWriteStream();
// Do the conversion. This will replace the original HTML
// with a filtered version.
try
{
// The easiest way to do the conversion in one step is by using the Convert
// method. It creates an appropriate converter stream
// and copies from one stream to another.
htmlToHtmlConversion.Convert(originalBodyContent, newBodyContent);
}
catch (Microsoft.Exchange.Data.TextConverters.TextConvertersException)
{
// The conversion has failed.
}
}
else if (BodyFormat.Rtf == bodyFormat)
{
// This is compressed RTF body in a TNEF message.
// Compressed RTF body can contain the encapsulated original HTML to be
// filtered.
// Do not modify the message format here, just filter out
// potentially unsafe content. Convert RTF to HTML, filter out any
// unsafe HTML content, and convert the result back to RTF.
// Note that conversion from RTF to HTML and back to RTF can result in loss of data. Some
// embedded images in RTF can be lost and formatting can slightly change.
// First wrap the original body content, which is in a "compressed RTF" format, into
// a stream that will do RTF decompression. Reading from this stream
// will return original RTF (the same format that the Word and RichEdit controls are using).
ConverterStream uncompressedRtf = new ConverterStream(originalBodyContent, new RtfCompressedToRtf(), ConverterStreamAccess.Read);
// Create and configure the RtfToHtml conversion object.
RtfToHtml rtfToHtmlConversion = new RtfToHtml();
// Set up output HTML filtering. HTML filtering will ensure that
// no scripts or active content can pass through.
rtfToHtmlConversion.FilterHtml = true;
// Add a disclaimer to indicate that the body is being filtered.
rtfToHtmlConversion.HeaderFooterFormat = HeaderFooterFormat.Html;
rtfToHtmlConversion.Footer = "<p><font face=\"Arial\" size=1>the RTF body is being filtered</font></p>";
// Now create a wrapping TextReader object, which returns the filtered
// HTML converted (or extracted) from the original RTF.
ConverterReader html = new ConverterReader(uncompressedRtf, rtfToHtmlConversion);
// After you filter the HTML, convert it back to RTF. For the purposes of this sample, do not
// change the message format.
// Create and configure the HtmlToRtf conversion object.
HtmlToRtf htmlToRtfConversion = new HtmlToRtf();
// Create a wrapping stream that returns RTF converted back from filtered HTML.
ConverterStream filteredRtf = new ConverterStream(html, htmlToRtfConversion);
// Create and configure the RtfToRtfCompressed conversion object, which
// will compress the resulting RTF.
RtfToRtfCompressed rtfCompressionConversion = new RtfToRtfCompressed();
// Always write it back in a compressed form.
rtfCompressionConversion.CompressionMode = RtfCompressionMode.Compressed;
// Open the stream to write updated body content into.
newBodyContent = body.GetContentWriteStream();
// Finally, perform the complete chain of conversions you set up. This
// will read the original compressed RTF chunk by chunk, convert it to HTML
// and filter scripts, then convert HTML back to RTF, compress it and write
// back into the current message body.
try
{
// Use the Convert method because it is convenient. This Convert
// method compresses the resulting RTF it reads from the conversion
// chain stream you set up and writes the result into the output stream.
// It saves a few lines of code that would be required to create another wrapper stream and
// copy from one stream to another.
rtfCompressionConversion.Convert(filteredRtf, newBodyContent);
}
catch (Microsoft.Exchange.Data.TextConverters.TextConvertersException)
{
// The conversion has failed.
}
}
else
{
// Handle cases where the body format is not one of the above.
}
}
finally
{
if (originalBodyContent != null)
{
originalBodyContent.Close();
}
if (newBodyContent != null)
{
newBodyContent.Close();
}
}
}
