I have a .Net Core MVC Web application that authenticates the user using AzureAD. At some stage I need to send an e-mail on behalf of that user.
I searched for some options and apparently I can do that using Microsoft Exchange Service or Office365 but for both options I need to get the user's credential.
An example using Office365 is below however I do not know how to user the signed in info to pass to the SMTP server.
My (partial) HomeController:
private readonly ClaimsPrincipal _principal;
public HomeController(IPrincipal principal){
_principal = principal as ClaimsPrincipal;
}
I can use _principal.FindFirst(ClaimTypes.Upn).Value to get the user's e-mail address but how do I get the password?
Am I in the right path or am I missing anything?
public static void SendEmail(string toAddress, string fromAddress, string subject, string content)
{
SmtpClient client = new SmtpClient();
client.Credentials = new NetworkCredential("", "");
client.Port = 587;
client.Host = "smtp.office365.com";
client.EnableSsl = true;
MailMessage newMail = new MailMessage();
newMail.To.Add(toAddress);
newMail.From = new MailAddress(fromAddress);
newMail.Subject = subject;
newMail.IsBodyHtml = true;
newMail.Body = "<html><body>" + content + "</body></html>";
client.Send(newMail);
}
I'm sorry if this is a broad question but I really need some light on how to achieve this. I'm happy to provide more details if necessary.
At some stage I need to send an e-mail on behalf of that user.
Per my understanding, you could use the cloud-based email service SendGrid to handle email delivery on behalf of your authenticated user's email address. The code for sending the email to test02#example.com for the user test01#example.com would look like this:
var client = new SendGridClient("<SendGrid-ApiKey>");
var msg = new SendGridMessage()
{
From = new EmailAddress("test01#example.com", "test01"),
Subject = "Hello World from the SendGrid CSharp SDK!",
PlainTextContent = "Hello, Email!",
HtmlContent = "<strong>Hello, Email!</strong>"
};
msg.AddTo(new EmailAddress("test02#example.com", "Test02"));
var response = await client.SendEmailAsync(msg);
Detailed tutorial, you could follow sendgrid-csharp.
Based on this tutorial, I'm trying to get contacts photos
private String createPhoto() {
try {
AttachmentCollection attachments = contact.getAttachments();
for (Attachment attachment : attachments.getItems()) {
if (attachment instanceof FileAttachment) {
boolean isPhoto = ((FileAttachment) attachment).isContactPhoto();
if (isPhoto) {
attachment.load();
FileAttachment photo = contact.getContactPictureAttachment();
String filename = photo.getName() + ".jpg";
photo.load(new FileOutputStream(filename, true));
return filename;
}
}
}
} catch (Exception ex) {
LOGGER.info("" + ex);
}
return null;
}
However, attachments.getItems() is always an empty array.
On my mailbox, I have few contacts with photos, and I can receive them by calling URL https://companyname.exchange.com/EWS/Exchange.asmx/s/GetUserPhoto?email=name#company.exchange.com&size=HR360x360
Why I can't get a photo from the code?
On my mailbox, I have few contacts with photos, and I can receive them by calling URL https://companyname.exchange.com/EWS/Exchange.asmx/s/GetUserPhoto?email=name#company.exchange.com&size=HR360x360
That request gets the Userphoto which is stored in the (Source)Users Mailbox (or low res in ActiveDirectory) and made available by that operation.
Your code is trying to retrieve the ContactPhoto which can be stored as an attachment on Contacts in a UserMailbox.
So these are two separate things so which one are you dealing with ?, As you haven't shown it you need to make sure you ExchangeServerRequest Version is set to 2010 or greater as Contact photos aren't returned in 2007. You might also want to test quickly the contacts in Question with the EWS Editor https://ewseditor.codeplex.com/ that will allow you to get the objects and see if there is a ContactPhoto Attachments using EWS.
I am developing an UWP Application , i want to add a Attachment to outlook from UWP app programmatically
Request you to please me know if any alternatives are there.
Looking forward for your response.
You can use the share contract to send some data to the compliant applications (including outlook). It allows you to share some text and data with any compliant apps.
To activate the sharing, you just need to register to the DataRequested event and show the share UI:
DataTransferManager.GetForCurrentView().DataRequested += OnDataRequested;
DataTransferManager.ShowShareUI();
Then, in the event handler:
private async void OnDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
var deferral = args.Request.GetDeferral();
try
{
args.Request.Data.Properties.Title = "Share Title"
args.Request.Data.Properties.Description = "Share some data/file";
var file = await ApplicationData.Current.TemporaryFolder.GetFileAsync("myFileToShare.xxx");
args.Request.Data.SetStorageItems(new IStorageItem[] { logFile });
}
catch
{
args.Request.FailWithDisplayText("Unable to share data");
}
finally
{
deferral.Complete();
sender.DataRequested -= OnDataRequested;
}
}
Once done, the system will show the share UI where the user will be able to select the app he want. This app will receive the sent data.
While #Vincent's answer is perfect when you want to use Share Contract, if you want to use Just Email and attach the File, Below is a simple Method that i use in one of my App.
internal async void ShowEmail(string body, string subject, StorageFile attachment)
{
EmailMessage email = new EmailMessage();
email.Subject = subject;
email.Body = body;
var stream = RandomAccessStreamReference.CreateFromFile(attachment);
email.SetBodyStream(EmailMessageBodyKind.Html, stream);
await EmailManager.ShowComposeNewEmailAsync(email);
}
Above method is a strip down of the example from Here
I am trying to send an email address in my application as someone (email should show up as if it were sent from that), but anytime I send the email, the name shows up as I supplied, but no matter what I do, the email address is what I am using to authenticate.
Is there any way to have the email to appear as if it is coming from someone I specify or will it always show up as coming from the authenticated email?
Here is what I have...
using (var message = new MailMessage()
{
From = From != new MailAddress(From.Email, From.FormalName),
Subject = Subject,
Body = Body
})
{
if (To != null)
{
foreach (var address in To)
{
message.To.Add(new MailAddress(address.Email, address.FormalName));
}
}
if (CC != null)
{
foreach (var address in CC)
{
message.CC.Add(new MailAddress(address.Email, address.FormalName));
}
}
var smtp = new SmtpClient
{
Host = "smtp.gmail.com",
Port = 587,
EnableSsl = true,
DeliveryMethod = SmtpDeliveryMethod.Network,
UseDefaultCredentials = false,
Credentials = new NetworkCredential("myaccount", "mypassword")
};
message.IsBodyHtml = true;
message.Headers.Add("Reply-To", message.From.Address);
smtp.Send(message);
}
It looks like you're expecting the Reply-To: header to indicate who the message is from. In fact, there is a header called From: for this purpose. So try:
message.Headers.Add("From", message.From.Address);
Do note that Gmail will probably add a Sender: header (that may or may not be shown by the recipient's email client) that reflects the actual account you used to send the message.
Best practice when sending automated emails from a specific user is to use the 'on behalf of' syntax (ReplyTo or Sender in MailMessage) in conjunction with a from address from your system see Sending "on behalf of" emails
however you can put the address straight into from as a string so long as your mail server supports it and the receiving mail server does not do a reverse look-up
I need to send hundreds of newsletters, but would like to check first if email exists on server. It's called SMTP validation, at least I think so, based on my research on Internet.
There's several libraries that can do that, and also a page with open-source code in ASP Classic (http://www.coveryourasp.com/ValidateEmail.asp#Result3), but I have hard time reading ASP Classic, and it seems that it uses some third-party library...
Is there some code for SMTP validation in C#, and/or general explanation of how it works?
Be aware that most MTAs (Mail Transfer Agent) will have the VRFY command turned off for spam protection reasons, they'll probably even block you if you try several RCPT TO in a row (see http://www.spamresource.com/2007/01/whatever-happened-to-vrfy.html). So even if you find a library to do that verification, it won't be worth a lot. Ishmaeel is right, the only way to really find out, is sending an email and see if it bounces or not.
#Hrvoje: Yes, I'm suggesting you monitor rejected emails. BUT: not all the bounced mails should automatically end up on your "does not exist"-list, you also have to differentiate between temporary (e.g. mailbox full) and permanent errors.
SMTP is a text based protocol carried over TCP/IP.
Your validation program needs to open a TCP/IP connection to the server's port 25 (SMTP), write in a few lines and read the answer. Validation is done (but not always) on the "RCTP TO" line and on the "VFRY" line.
The SMTP RFC describes how this works (see Green#Beta.ARPA below, S are lines sent by the client, R are lines received from the server):
Example of the SMTP Procedure
This SMTP example shows mail sent by Smith at host Alpha.ARPA,
to Jones, Green, and Brown at host Beta.ARPA. Here we assume
that host Alpha contacts host Beta directly.
S: MAIL FROM:
R: 250 OK
S: RCPT TO:
R: 250 OK
S: RCPT TO:
R: 550 No such user here
While it's true that many domains will return false positives because of abuse, there are still some great components out there that will perform several levels of validation beyond just the SMTP validation. For example, it's worth it to check first to see if at least the domain exists. I'm in the process of compiling my own list of resources related to this question which you can track here:
http://delicious.com/dworthley/email.validation (broken link)
For those who might want to add to this list, I'll also include what I currently have here:
aspNetMX
.NET Email Validation Wizard Class Library
MONOProg Email Validator.Net
For a bulletproof form and a great user experience, it's helpful to validate as many aspects of the email address as possible. I can see from the aspNetMX validator that they check:
the syntax
the email against a list of bad email addresses
the domain against a list of bad domains
a list of mailbox domains
whether or not the domain exists
whether there are MX records for the domain
and finally through SMTP whether or not a mailbox exists
It's this last step that can be circumvented by administrators by returning true to basically all account verification requests, but in most cases if the user has intentionally entered a bad address it's already been caught. And if it was user error in the domain part of the address, that will be caught too.
Of course, a best practice for using this kind of a service for a registration screen or form would be to combine this kind of validation with a verification process to ensure that the email address is valid. The great thing about using an email validator in front of a verification process is that it will make for a better overall user experience.
You can try the below code, it works fine for me :
public class EmailTest {
private static int hear(BufferedReader in) throws IOException {
String line = null;
int res = 0;
while ((line = in.readLine()) != null) {
String pfx = line.substring(0, 3);
try {
res = Integer.parseInt(pfx);
} catch (Exception ex) {
res = -1;
}
if (line.charAt(3) != '-')
break;
}
return res;
}
private static void say(BufferedWriter wr, String text) throws IOException {
wr.write(text + "\r\n");
wr.flush();
return;
}
#SuppressWarnings({ "rawtypes", "unchecked" })
private static ArrayList getMX(String hostName) throws NamingException {
// Perform a DNS lookup for MX records in the domain
Hashtable env = new Hashtable();
env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
DirContext ictx = new InitialDirContext(env);
Attributes attrs = ictx.getAttributes(hostName, new String[] { "MX" });
Attribute attr = attrs.get("MX");
// if we don't have an MX record, try the machine itself
if ((attr == null) || (attr.size() == 0)) {
attrs = ictx.getAttributes(hostName, new String[] { "A" });
attr = attrs.get("A");
if (attr == null)
throw new NamingException("No match for name '" + hostName + "'");
}
/*
Huzzah! we have machines to try. Return them as an array list
NOTE: We SHOULD take the preference into account to be absolutely
correct. This is left as an exercise for anyone who cares.
*/
ArrayList res = new ArrayList();
NamingEnumeration en = attr.getAll();
while (en.hasMore()) {
String mailhost;
String x = (String) en.next();
String f[] = x.split(" ");
// THE fix *************
if (f.length == 1)
mailhost = f[0];
else if (f[1].endsWith("."))
mailhost = f[1].substring(0, (f[1].length() - 1));
else
mailhost = f[1];
// THE fix *************
res.add(mailhost);
}
return res;
}
#SuppressWarnings("rawtypes")
public static boolean isAddressValid(String address) {
// Find the separator for the domain name
int pos = address.indexOf('#');
// If the address does not contain an '#', it's not valid
if (pos == -1)
return false;
// Isolate the domain/machine name and get a list of mail exchangers
String domain = address.substring(++pos);
ArrayList mxList = null;
try {
mxList = getMX(domain);
} catch (NamingException ex) {
return false;
}
/*
Just because we can send mail to the domain, doesn't mean that the
address is valid, but if we can't, it's a sure sign that it isn't
*/
if (mxList.size() == 0)
return false;
/*
Now, do the SMTP validation, try each mail exchanger until we get
a positive acceptance. It *MAY* be possible for one MX to allow
a message [store and forwarder for example] and another [like
the actual mail server] to reject it. This is why we REALLY ought
to take the preference into account.
*/
for (int mx = 0; mx < mxList.size(); mx++) {
boolean valid = false;
try {
int res;
//
Socket skt = new Socket((String) mxList.get(mx), 25);
BufferedReader rdr = new BufferedReader(new InputStreamReader(skt.getInputStream()));
BufferedWriter wtr = new BufferedWriter(new OutputStreamWriter(skt.getOutputStream()));
res = hear(rdr);
if (res != 220)
throw new Exception("Invalid header");
say(wtr, "EHLO rgagnon.com");
res = hear(rdr);
if (res != 250)
throw new Exception("Not ESMTP");
// validate the sender address
say(wtr, "MAIL FROM: <tim#orbaker.com>");
res = hear(rdr);
if (res != 250)
throw new Exception("Sender rejected");
say(wtr, "RCPT TO: <" + address + ">");
res = hear(rdr);
// be polite
say(wtr, "RSET");
hear(rdr);
say(wtr, "QUIT");
hear(rdr);
if (res != 250)
throw new Exception("Address is not valid!");
valid = true;
rdr.close();
wtr.close();
skt.close();
} catch (Exception ex) {
// Do nothing but try next host
ex.printStackTrace();
} finally {
if (valid)
return true;
}
}
return false;
}
public static void main(String args[]) {
String testData[] = { "rahul.saraswat#techblue.com", "rahul.saraswat#techblue.co.uk", "srswt.rahul12345#gmail.com",
"srswt.rahul#gmail.com" };
System.out.println(testData.length);
for (int ctr = 0; ctr < testData.length; ctr++) {
System.out.println(testData[ctr] + " is valid? " + isAddressValid(testData[ctr]));
}
return;
}
}
Thanks & Regards
Rahul Saraswat
The Real(TM) e-mail validation is trying to send something to the address, and seeing if it is rejected/bounced. So, you'll just have to send them away, and remove the addresses that fail from your mailing list.
Don't take this the wrong way, but sending newsletters to more than a handful of people these days is a fairly serious matter. Yes, you need to be monitoring bounces (rejected emails) which can occur synchronously during the SMTP send (typically if the SMTP server you are connected to is authoritative), or asynchronously as a system-generated email message that occurs some amount of time after the SMTP send succeeded.
Also keep the CAN-SPAM Act in mind and abide by the law when sending these emails; you've got to provide an unsub link as well as a physical street address (to both identify you and t0 allow users to send unsub requests via snail-mail if they so choose).
Failure to do these things could get your IP null-routed at best and sued at worst.
You may need this Email Validator component for .NET
Here is the code example:
// Create a new instance of the EmailValidator class.
EmailValidator em = new EmailValidator();
em.MessageLogging += em_MessageLogging;
em.EmailValidated += em_EmailValidationCompleted;
try
{
string[] list = new string[3] { "test1#testdomain.com", "test2#testdomain.com", "test3#testdomain.com" };
em.ValidateEmails(list);
}
catch (EmailValidatorException exc2)
{
Console.WriteLine("EmailValidatorException: " + exc2.Message);
}