Email Sending API

Sending Methods

To send emails, use the following methods of the Emailer bean:

sendEmail() – synchronous message sending. The calling code is blocked while sending the message to the SMTP server. You can specify the message either by a set of parameters – the comma-separated list of recipients, subject, content, an array of attachments; or as a special EmailInfo object which encapsulates all this information and allows you to explicitly set the sender’s address.

Here is an example of sending email using EmailInfo object:
```
@Autowired
private Emailer emailer;

private void sendByEmailInfo() throws EmailException {
    EmailInfo emailInfo = EmailInfoBuilder.create("john.doe@company.com",
            "Email subject", "Email body")
            .build();
    emailer.sendEmail(emailInfo);
}
```
During synchronous sending, the framework can throw EmailException with the information about failed recipient addresses and corresponding error messages.

One SendingMessage instance is created in the database for all recipients during the execution of the method. It has the initial SendingStatus.SENDING status, and SendingStatus.SENT after successful sending. In case of a message sending error, the message status changes to SendingStatus.NOT_SENT.
sendEmailAsync() – asynchronous message sending. This method returns SendingMessage instance in SendingStatus.QUEUE status, which was created in the database. The actual sending is performed later by the Emailer.processQueuedEmails() method which should be called by a scheduler.

Email Attachments

The EmailAttachment object is a wrapper that holds the attachment as a byte array, a file name, and, if necessary, an attachment identifier which is unique for this message.

EmailAttachment emailAtt = new EmailAttachment(bytes, "logo.png", "logoId");

The attachment identifier is an optional but useful field when you want to insert images in the message body. For this, specify a unique contentId when creating EmailAttachment, as logoId in the example above. To insert the image in the message body, use an expression like cid:logoId as a path to attachment, for example:

<img src="cid:logoId"/>

Also, you can create a text attachment from the string and specify an encoding and the name of the attachment file. In the example, an attachment is created and sent with email:

String att = "<html><body><h1>Content of attachment</h1></body></html>";
EmailAttachment emailAtt = EmailAttachment.createTextAttachment(att, StandardCharsets.UTF_8.name(), "attachment.html");