/// <summary>
/// Get the decoded text and the encoding used to convert it into unicode.
/// </summary>
/// <remarks>
/// <para>If the charset parameter on the <see cref="MimeEntity.ContentType"/>
/// is set, it will be used in order to convert the raw content into unicode.
/// If that fails or if the charset parameter is not set, the first 2 bytes of
/// the content will be checked for a unicode BOM. If a BOM exists, then that
/// will be used for conversion. If no BOM is found, then UTF-8 is attempted.
/// If conversion fails, then iso-8859-1 will be used as the final fallback.</para>
/// <para>For more control, use <see cref="GetText(Encoding)"/>
/// or <see cref="GetText(String)"/>.</para>
/// </remarks>
/// <param name="encoding">The encoding used to convert the text into unicode.</param>
/// <returns>The decoded text.</returns>
public string GetText(out Encoding encoding)
{
if (Content == null)
{
encoding = Encoding.ASCII;
return(string.Empty);
}
encoding = ContentType.CharsetEncoding;
if (encoding == null)
{
try {
using (var content = Content.Open()) {
if (!CharsetUtils.TryGetBomEncoding(content, out encoding))
{
encoding = CharsetUtils.UTF8;
}
}
return(GetText(encoding));
} catch (DecoderFallbackException) {
// fall back to iso-8859-1
encoding = CharsetUtils.Latin1;
}
}
return(GetText(encoding));
}
/// <summary>
/// Get a text preview of the text part.
/// </summary>
/// <remarks>
/// Gets a text preview of the text part.
/// </remarks>
/// <param name="body">The text part.</param>
/// <returns>A string representing a shortened preview of the original text.</returns>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="body"/> is <c>null</c>.
/// </exception>
public static string GetPreviewText(TextPart body)
{
if (body == null)
{
throw new ArgumentNullException(nameof(body));
}
if (body.Content == null)
{
return(string.Empty);
}
var encoding = body.ContentType.CharsetEncoding;
var buffer = new byte[16 * 1024];
int nread = 0;
using (var content = body.Content.Open()) {
int n;
do
{
if ((n = content.Read(buffer, nread, buffer.Length - nread)) <= 0)
{
break;
}
nread += n;
} while (nread < buffer.Length);
}
if (encoding == null)
{
if (!CharsetUtils.TryGetBomEncoding(buffer, nread, out encoding))
{
encoding = CharsetUtils.UTF8;
}
}
using (var stream = new MemoryStream(buffer, 0, nread, false)) {
var previewer = Create(body.Format);
try {
return(previewer.GetPreviewText(stream, encoding));
} catch (DecoderFallbackException) {
stream.Position = 0;
return(previewer.GetPreviewText(stream, CharsetUtils.Latin1));
}
}
}
