Module email
![](https://bcentral-packageicons.azureedge.net/images/ballerina_email_2.5.1.png)
ballerina/email Ballerina library
Overview
This module provides APIs to perform email operations such as sending and reading emails using the SMTP, POP3, and IMAP4 protocols.
Client
This module supports the following three client types.
email:SmtpClient: The client, which supports sending an email using the SMTP protocol.
email:PopClient: The client, which supports receiving an email using the POP3 protocol.
email:ImapClient: The client, which supports receiving an email using the IMAP4 protocol.
SMTP client
To send an email using the SMTP protocol, you must first create an email:SmtpClient
object. The code for creating an email:SmtpClient
can be found
below.
Create a client
The following code creates an SMTP client, which connects to the default port (i.e. 465) and enables SSL.
email:SmtpClient smtpClient = check new ("smtp.email.com", "sender@email.com", "pass123");
The port number of the server can be configured by passing the following configurations.
email:SmtpConfiguration smtpConfig = { port: 465 }; email:SmtpClient smtpClient = check new ("smtp.email.com", "sender@email.com", "pass123", smtpConfig);
Send an email
Once the email:SmtpClient
is created, an email can be sent using the SMTP protocol through that client.
Samples for this operation can be found below.
email:Message email = { to: ["receiver1@email.com", "receiver2@email.com"], cc: ["receiver3@email.com", "receiver4@email.com"], bcc: ["receiver5@email.com"], subject: "Sample Email", body: "This is a sample email.", 'from: "author@email.com", sender: "sender@email.com", replyTo: ["replyTo1@email.com", "replyTo2@email.com"] }; check smtpClient->sendMessage(email);
An email can be sent directly by calling the client specifying optional parameters as named parameters as well. Samples for this operation can be found below.
email:Error? response = smtpClient->send( ["receiver1@email.com", "receiver2@email.com"], "Sample Email", "author@email.com", body="This is a sample email.", cc=["receiver3@email.com", "receiver4@email.com"], bcc=["receiver5@email.com"], sender="sender@email.com", replyTo=["replyTo1@email.com", "replyTo2@email.com"] );
POP3 client
To receive an email using the POP3 protocol, you must first create an email:PopClient
object. The code for creating an
email:PopClient
can be found below.
Create a client
The following code creates a POP3 client, which connects to the default port (i.e. 995) and enables SSL.
email:PopClient popClient = check new ("pop.email.com", "reader@email.com", "pass456");
The port number of the server can be configured by passing the following configurations.
email:PopConfiguration popConfig = { port: 995 }; email:PopClient popClient = check new ("pop.email.com", "reader@email.com", "pass456", popConfig);
Receive an email
Once the email:PopClient
is created, emails can be received using the POP3 protocol through that client.
Samples for this operation can be found below.
email:Message? emailResponse = check popClient->receiveMessage();
IMAP4 client
To receive an email using the IMAP4 protocol, you must first create an email:ImapClient
object. The code for creating an
email:ImapClient
can be found below.
Create a client
The following code creates an IMAP4 client, which connects to the default port (i.e. 993) and enables SSL.
email:ImapClient imapClient = check new ("imap.email.com", "reader@email.com", "pass456");
The port number of the server can be configured by passing the following configuration.
email:ImapConfiguration imapConfig = { port: 993 }; email:ImapClient imapClient = check new ("imap.email.com", "reader@email.com", "pass456", imapConfig);
Receive an email
Once the email:ImapClient
is created, emails can be received using the IMAP4 protocol through that client.
Samples for this operation can be found below.
email:Message? emailResponse = check imapClient->receiveMessage();
POP3 and IMAP listeners
As POP3 and IMAP4 protocols are similar in the listener use cases, POP3 is considered in the examples below.
In order to receive emails one-by-one from a POP3 server, you must first create an email:PopListener
object.
The code for creating an email:PopListener
can be found below.
listener email:PopListener emailListener = check new ({ host: "pop.email.com", username: "reader@email.com", password: "pass456", pollingInterval: 2, port: 995 });
Once initialized, a service
can listen to the new emails as follows. New emails get received at the onMessage
method and when errors happen, the onError
method gets called.
service "emailObserver" on emailListener { remote function onMessage(email:Message emailMessage) { io:println("Email Subject: ", emailMessage.subject); io:println("Email Body: ", emailMessage.body); } remote function onError(email:Error emailError) { io:println("Error while polling for the emails: " + emailError.message()); } }
Security and authentication
The email
module supports both the TLS/SSL and STARTTLS as transport-level security protocols.
Transport-level security for all SMTP, POP3, and IMAP clients/listeners can be configured with the secureSocket
field.
secureSocket: { cert: "path/to/certfile.crt", protocol: { name: TLS, versions: ["TLSv1.2", "TLSv1.1"] }, ciphers: ["TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA"], verifyHostName: true }
Transport-level security for the SMTP client configuration can be defined as follows.
email:SmtpConfiguration smtpConfig = { port: 465, secureSocket: { // Transport level configuration } };
Transport-level security for the POP3 client configuration can be defined as follows.
email:PopConfiguration popConfig = { port: 995, secureSocket: { // Transport level configuration } };
Transport-level security for the IMAP client configuration can be defined as follows.
email:ImapConfiguration imapConfig = { port: 993, secureSocket: { // Transport level configuration } };
Transport-level security for the POP3 listener configuration can be defined as follows.
email:PopListenerConfiguration popListenerConfig = { host: "127.0.0.1", username: "hascode", password: "abcdef123", pollingInterval: 2, port: 995, secureSocket: { // Transport level configuration } };
Transport-level security for the IMAP listener configuration can be defined as follows.
email:ImapListenerConfiguration imapListenerConfig = { host: "127.0.0.1", username: "hascode", password: "abcdef123", pollingInterval: 2, port: 993, secureSocket: { // Transport level configuration } };
By default, TLS/SSL is enabled as the default transport-level security protocol, and the certificate verification is set as required.
This optional protocol definition can be configured with the security
enum
field in each of the configuration types described above.
The options available with the security
field are as follows.
SSL: As same as the default TLS/SSL protocol
START_TLS_NEVER: Disables both TLS/SSL and STARTTLS protocols and allows only the unencrypted transport-level communication
START_TLS_ALWAYS: Makes it mandatory to use the secure STARTTLS protocol
START_TLS_AUTO: Enables the STARTTLS protocol, which would switch to the unsecured communication mode if the secure STARTTLS mode is not available in the server
The following is an example of using the security
field in the SMTP client with the START_TLS_AUTO
mode.
email:SmtpConfiguration smtpConfig = { port: 587, secureSocket: { // Transport level configuration }, security: START_TLS_AUTO };
Similarly, other client/listener configuration types can also be defined with the security
field.
Note: Make sure the port number is changed accordingly depending on the protocol used.
Standard port numbers used for each of the protocol for each type of transport security are as given below.
Protocol/Security | SSL | STARTTLS | Unsecure |
---|---|---|---|
SMTP | 465 | 587 | 25, 587 |
POP3 | 995 | 995 | 110 |
IMAP4 | 993 | 143, 993 | 143 |
All the authentications are based on the username/password credentials.
Note: When the
'from
field is not provided in anemail:Message
, theusername
field of the initialization argument of theemail:SmtpClient
is set as thefrom
address of an email to be sent with SMTP.
Message content and
An email:Message
prepared to be sent can have the text body content, body
, and/or HTML body content (htmlBody
).
When emails are received with POP3 or IMAP, the text email bodies and HTML bodies of the email are captured by the body
and htmlBody
fields of the email:Message
respectively.
When sending emails with SMTP, there are four options to specify the email attachments
in the email:Message
.
- With the
email:Attachment
type, which points to an attachment file along with its content-type - With an array of the
email:Attachment
type - With the
mime:Entity
type - With an array of the
mime:Entity
type
Option 1 and 2 are designed for ordinary users to attach files from the local machine along with its content-type. Option 3 and 4 are designed for advanced users who have programming knowledge to define complex MIME typed data attachments.
The following is an example of attaching a PDF file to an email with option 1.
email:Attachment pdfAttachment = {filePath: "path/to/application.pdf", contentType: "application/pdf"}; email:Message email = { // Other fields attachments: pdfAttachment };
The following is an example of attaching a JPG file to an email with option 3.
mime:Entity imageAttachment = new; mime:ContentDisposition disposition = new; disposition.fileName = "profilePic.jpg"; disposition.disposition = "attachment"; disposition.name = "profilePic"; imageAttachment.setContentDisposition(disposition); imageAttachment.setContentId("ImageAttachment"); imageAttachment.setFileAsEntityBody("path/to/profilePic.jpg", mime:IMAGE_JPEG); email:Message email = { // Other fields attachments: imageAttachment };