trying to send email with gmail api receive 'raw' RFC822 payload message string

Question

I\'m trying to perform a simple Reply to email with Gmail API.

I\'m receiving the following error:

Google.GoogleApiException: \'Google.Apis.Re

Answer 1

You could resort to using third party MIME library with below steps:

1. Download the gmail message in raw format
2. Parse the raw message using library
3. Modify the message
4. Output it back to raw format using library
5. Insert back into the gmail message and then send.

Have a look at this solution on SO https://stackoverflow.com/a/26599752/2637802

Using the MimeKit library heres sample code:

var msgRequest = service.Users.Messages.Get("me", msg.Id);
msgRequest.Format = UsersResource.MessagesResource.GetRequest.FormatEnum.Raw;
var msgDetails = msgRequest.Execute();

using (MemoryStream rawInStream = new MemoryStream(Base64FUrlDecode(msgDetails.Raw)))
using (MemoryStream rawOutStream = new MemoryStream())
{
    var message = MimeKit.MimeMessage.Load(rawInStream);

    message.To.Clear();
    message.To.Add(new MimeKit.MailboxAddress("", ""));
    message.Subject = "Edited Subject";

    message.WriteTo(rawOutStream);
    msgDetails.Raw = Base64UrlEncode(rawOutStream.ToArray());
}

service.Users.Messages.Send(msgDetails, "me").Execute();

private static byte[] Base64FUrlDecode(string input)
{
    int padChars = (input.Length % 4) == 0 ? 0 : (4 - (input.Length % 4));
    StringBuilder result = new StringBuilder(input, input.Length + padChars);
    result.Append(String.Empty.PadRight(padChars, '='));
    result.Replace('-', '+');
    result.Replace('_', '/');
    return Convert.FromBase64String(result.ToString());
}

private static string Base64UrlEncode(byte[] input)
{
    // Special "url-safe" base64 encode.
    return Convert.ToBase64String(input)
      .Replace('+', '-')
      .Replace('/', '_')
      .Replace("=", "");
}