///<summary>Helper method that creates a new MIME message based on the parameters (to, cc, bcc, from, and body)</summary>
private static MimeMessage CreateMIMEMsg(BasicEmailAddress emailAddress, BasicEmailMessage emailMessage)
{
MimeMessage mimeMsg = new MimeMessage();
Multipart multipart = new Multipart();
mimeMsg.From.Add(new MailboxAddress(emailAddress.EmailUsername));
if (!emailMessage.Subject.IsNullOrEmpty())
{
mimeMsg.Subject = emailMessage.Subject;
}
//Create MailAddress objects for all addresses.
//MailAddress will automatically parse out "DisplayName" <*****@*****.**> and every variation
MailAddress toAddress = new MailAddress(emailMessage.ToAddress.Trim());
mimeMsg.To.Add(new MailboxAddress(toAddress.DisplayName, toAddress.Address));
if (!emailMessage.CcAddress.IsNullOrEmpty())
{
MailAddress ccAddress = new MailAddress(emailMessage.CcAddress.Trim());
mimeMsg.Cc.Add(new MailboxAddress(ccAddress.DisplayName, ccAddress.Address));
}
if (!emailMessage.BccAddress.IsNullOrEmpty())
{
MailAddress bccAddress = new MailAddress(emailMessage.BccAddress.Trim());
mimeMsg.Cc.Add(new MailboxAddress(bccAddress.DisplayName, bccAddress.Address));
}
if (emailMessage.ListAttachments != null)
{
foreach (Tuple <string, string> attachmentPath in emailMessage.ListAttachments)
{
multipart.Add(new MimePart()
{
Content = new MimeContent(File.OpenRead(attachmentPath.Item1)),
ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
ContentTransferEncoding = ContentEncoding.Base64,
FileName = Path.GetFileName(attachmentPath.Item1)
});
}
}
if (emailMessage.IsHtml)
{
multipart.Add(new TextPart(MimeKit.Text.TextFormat.Html)
{
Text = emailMessage.HtmlBody
});
}
else
{
multipart.Add(new TextPart()
{
Text = emailMessage.BodyText
});
}
mimeMsg.Body = multipart;
return(mimeMsg);
}
///<summary>Helper method that returns a ready-to-send Gmail Message</summary>
private static GmailApi.Data.Message CreateGmailMsg(BasicEmailAddress emailAddress, BasicEmailMessage emailMessage)
{
MimeKit.MimeMessage mimeMsg = CreateMIMEMsg(emailAddress, emailMessage);
using Stream stream = new MemoryStream();
mimeMsg.WriteTo(stream);
stream.Position = 0;
using StreamReader sr = new StreamReader(stream);
GmailApi.Data.Message gMsg = new GmailApi.Data.Message();
string rawString = sr.ReadToEnd();
byte[] raw = System.Text.Encoding.UTF8.GetBytes(rawString);
gMsg.Raw = System.Convert.ToBase64String(raw);
//What we send to Gmail must be a Base64 File/URL safe string. We must convert our base64 to be URL safe. (replace - and _ with + and / respectively)
gMsg.Raw = gMsg.Raw.Replace("+", "-");
gMsg.Raw = gMsg.Raw.Replace("/", "_");
return(gMsg);
}
///<summary>Throws exceptions if failing to send emails or authenticate with Google.</summary>
private static void SendEmailOAuth(BasicEmailAddress address, BasicEmailMessage message)
{
using GmailApi.GmailService gService = GoogleApiConnector.CreateGmailService(address);
try {
GmailApi.Data.Message gmailMessage = CreateGmailMsg(address, message);
gService.Users.Messages.Send(gmailMessage, address.EmailUsername).Execute();
}
catch (GoogleApiException gae) {
gae.DoNothing();
//This will bubble up to the UI level and be caught in a copypaste box.
throw new Exception("Unable to authenticate with Google: " + gae.Message);
}
catch (Exception ex) {
//This will bubble up to the UI level and be caught in a copypaste box.
throw new Exception($"Error sending email with OAuth authorization: {ex.Message}");
}
}
///<summary>Throws exceptions. Attempts to physically send the message over the network wire. This is used from wherever email needs to be
///sent throughout the program. If a message must be encrypted, then encrypt it before calling this function. nameValueCollectionHeaders can
///be null.</summary>
public static void WireEmailUnsecure(BasicEmailAddress address, BasicEmailMessage emailMessage, NameValueCollection nameValueCollectionHeaders,
params AlternateView[] arrayAlternateViews)
{
//For now we only support OAuth for Gmail but this may change in the future.
if (!address.AccessToken.IsNullOrEmpty() && address.SMTPserver == "smtp.gmail.com")
{
SendEmailOAuth(address, emailMessage);
}
else
{
bool isImplicitSsl = (address.ServerPort == 465);
if (isImplicitSsl) //Microsoft CDO supports implicit SSL, System.Net.Mail.SmtpClient only supports explicit SSL.
{
var cdo = new Message();
var cfg = cdo.Configuration;
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/smtpserver"].Value = address.SMTPserver;
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/smtpserverport"].Value = address.ServerPort;
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/sendusing"].Value = "2"; //sendusing: 1=pickup, 2=port, 3=using microsoft exchange
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"].Value = "1"; //0=anonymous,1=clear text auth,2=context (NTLM)
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/sendusername"].Value = address.EmailUsername.Trim();
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/sendpassword"].Value = address.EmailPassword;
cfg.Fields["http://schemas.microsoft.com/cdo/configuration/smtpusessl"].Value = true; //false was also tested and does not work
if (nameValueCollectionHeaders != null)
{
//How to add headers which do not have formal fields - https://msdn.microsoft.com/en-us/library/ms526317(v=exchg.10).aspx
string[] arrayHeaderKeys = nameValueCollectionHeaders.AllKeys;
for (int i = 0; i < arrayHeaderKeys.Length; i++) //Needed for Direct Acks to work.
{
string headerName = arrayHeaderKeys[i];
string headerValue = nameValueCollectionHeaders[headerName];
cfg.Fields["urn:schemas:mailheader:" + headerName].Value = headerValue;
}
}
cfg.Fields.Update();
cdo.From = emailMessage.FromAddress.Trim();
if (!string.IsNullOrWhiteSpace(emailMessage.ToAddress))
{
cdo.To = emailMessage.ToAddress.Trim();
}
if (!string.IsNullOrWhiteSpace(emailMessage.CcAddress))
{
cdo.CC = emailMessage.CcAddress.Trim();
}
if (!string.IsNullOrWhiteSpace(emailMessage.BccAddress))
{
cdo.BCC = emailMessage.BccAddress.Trim();
}
cdo.Subject = emailMessage.Subject;
if (emailMessage.IsHtml)
{
cdo.HTMLBody = emailMessage.HtmlBody;
if (!emailMessage.ListHtmlImages.IsNullOrEmpty())
{
foreach (string imagePath in emailMessage.ListHtmlImages)
{
var imgAttach = cdo.AddAttachment(imagePath);
imgAttach.Fields["urn:schemas:mailheader:content-id"].Value = HttpUtility.UrlEncode(Path.GetFileName(imagePath));
imgAttach.Fields.Update();
}
}
}
else
{
cdo.TextBody = emailMessage.BodyText;
}
if (!emailMessage.ListAttachments.IsNullOrEmpty())
{
foreach (Tuple <string, string> attachmentPath in emailMessage.ListAttachments)
{
var cdoatt = cdo.AddAttachment(attachmentPath.Item1);
//Use actual file name for this field.
cdoatt.Fields["urn:schemas:mailheader:content-id"].Value = Path.GetFileName(attachmentPath.Item1);
cdoatt.Fields.Update();
}
}
cdo.Send();
}
else //No SSL or explicit SSL on port 587
{
SmtpClient client = null;
MailMessage message = null;
try {
client = new SmtpClient(address.SMTPserver, address.ServerPort);
//The default credentials are not used by default, according to:
//http://msdn2.microsoft.com/en-us/library/system.net.mail.smtpclient.usedefaultcredentials.aspx
client.Credentials = new NetworkCredential(address.EmailUsername.Trim(), address.EmailPassword);
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.EnableSsl = address.UseSSL;
client.Timeout = 180000; //3 minutes
message = BasicEmailMessageToMailMessage(emailMessage, nameValueCollectionHeaders, arrayAlternateViews);
client.Send(message);
}
finally {
//Dispose of the client and messages here. For large customers, sending thousands of emails will start to fail until they restart the
//app. Freeing memory here can prevent OutOfMemoryExceptions.
client?.Dispose();
if (message != null)
{
if (message.Attachments != null)
{
message.Attachments.ForEach(x => x.Dispose());
}
message.Dispose();
}
}
}
}
}
