how to create imap receiver adapter dynamically using spring boot?

Question

How can i create direct channel, imap channel adapter and pass user account information so that program will start looking for new mails.

i have already implemented mail receiver using xml config.

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
    http://www.springframework.org/schema/integration/mail http://www.springframework.org/schema/integration/mail/spring-integration-mail.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd"
   xmlns:int="http://www.springframework.org/schema/integration"
   xmlns:int-mail="http://www.springframework.org/schema/integration/mail"
   xmlns:util="http://www.springframework.org/schema/util">

<int:channel id="emails"/>

<util:properties id="javaMailProperties">
    <prop key="mail.imap.socketFactory.class">javax.net.ssl.SSLSocketFactory</prop>
    <prop key="mail.imap.socketFactory.fallback">false</prop>
    <prop key="mail.store.protocol">imaps</prop>
    <prop key="mail.debug">true</prop>
</util:properties>

<int-mail:imap-idle-channel-adapter id="mailAdapter"
                              store-uri="imaps://login:pass@imap-server:993/INBOX"
                              java-mail-properties="javaMailProperties"
                              channel="emails"
                              should-delete-messages="false"
                              should-mark-messages-as-read="true">
</int-mail:imap-idle-channel-adapter>

Below is Java file which uses xml file.

public class EmailIntegrationTesting {

private static Logger logger = LoggerFactory.getLogger(EmailIntegrationTesting.class);

public static void main(String[] args) throws Exception {
    ApplicationContext ac = new ClassPathXmlApplicationContext("gmail-imap.xml");

    DirectChannel inputChannel = ac.getBean("receiveChannel", DirectChannel.class);
    inputChannel.subscribe(new MessageHandler() {
        @Override
        public void handleMessage(Message<?> message) throws MessagingException {


            MailToStringTransformer m2s = new MailToStringTransformer();
            m2s.setCharset("utf-8");
            System.out.println("Message: " + m2s.transform(message));

            System.out.println("Message: " + message.getPayload());
            Object payload = message.getPayload();

            if (payload instanceof MimeMessage) {
                try {

                    javax.mail.Message mailMessage = (javax.mail.Message) payload;
                    System.out.println(mailMessage.getSubject());
                    System.out.println(getTextFromMessage(mailMessage));

                    Address[] receipts = mailMessage.getAllRecipients();
                    System.out.println("RECEIPIENTS MAIL ID");
                    if (receipts != null && receipts.length > 0) {
                        for (int i = 0; i < receipts.length; i++) {
                            System.out.println(((InternetAddress) receipts[i]).getAddress());
                        }
                    }

                    System.out.println("FROM MAIL ID");
                    Address[] froms = mailMessage.getFrom();
                    String email = froms == null ? null
                            : ((InternetAddress) froms[0]).getAddress();
                    System.out.println(email);

                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        }
    });
}

private static String getTextFromMessage(javax.mail.Message message) throws Exception {
    String result = "";
    if (message.isMimeType("text/plain")) {
        result = message.getContent().toString();
    } else if (message.isMimeType("multipart/*")) {
        MimeMultipart mimeMultipart = (MimeMultipart) message.getContent();
        result = getTextFromMimeMultipart(mimeMultipart);
    }
    return result;
}

private static String getTextFromMimeMultipart(MimeMultipart mimeMultipart) throws Exception {
    String result = "";
    int count = mimeMultipart.getCount();
    for (int i = 0; i < count; i++) {
        BodyPart bodyPart = mimeMultipart.getBodyPart(i);
        if (bodyPart.isMimeType("text/plain")) {
            result = result + "\n" + bodyPart.getContent();
            break; // without break same text appears twice in my tests
        } else if (bodyPart.isMimeType("text/html")) {
            String html = (String) bodyPart.getContent();
            // result = result + "\n" + org.jsoup.Jsoup.parse(html).text();
        } else if (bodyPart.getContent() instanceof MimeMultipart) {
            result = result + getTextFromMimeMultipart((MimeMultipart) bodyPart.getContent());
        }
    }
    return result;
}

}

i can successfully receive mail using above code.

i can also convert xml to java config. below is the code.

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.mail.ImapIdleChannelAdapter;
import org.springframework.integration.mail.ImapMailReceiver;
import java.util.Properties;

@Configuration
class ImapConfiguration {

private Properties javaMailProperties() {
    Properties javaMailProperties = new Properties();

    javaMailProperties.setProperty("mail.imap.socketFactory.class","javax.net.ssl.SSLSocketFactory");
    javaMailProperties.setProperty("mail.imap.socketFactory.fallback","false");
    javaMailProperties.setProperty("mail.store.protocol","imaps");
    javaMailProperties.setProperty("mail.debug","true");

    return javaMailProperties;
}

@Bean
ImapIdleChannelAdapter mailAdapter() {
    ImapMailReceiver mailReceiver = new ImapMailReceiver("imaps://login:pass@imap-server:993/INBOX");

    mailReceiver.setJavaMailProperties(javaMailProperties());
    mailReceiver.setShouldDeleteMessages(false);
    mailReceiver.setShouldMarkMessagesAsRead(true);

    return new ImapIdleChannelAdapter(mailReceiver);
}

@Bean
public MessageChannel emails() {
 return new DirectChannel();
}

}

now, my point is i want to configure above code dynamically.

USECASE when user fill imap server details it should start looking for incoming emails. means i dont want to create bean at the time server start.

Answer 1

See my answer to this question and its follow-up.

You can also use the Java DSL to register flows dynamically...

@Autowired
private IntegrationFlowContext flowContext;

...

    IntegrationFlow flow = IntegrationFlows.from(Mail.imapIdleAdapter(...)
                            .handle(...)
                            ...
                            .get();
    IntegrationFlowRegistration flowRegistration =
                this.flowContext.registration(flow)
                        .register();

EDIT

Added a sample Boot application

@SpringBootApplication
public class So42297006Application {

    public static void main(String[] args) throws Exception {
        ConfigurableApplicationContext context = SpringApplication.run(So42297006Application.class, args);
        context.getBean(So42297006Application.class).runDemo();
        context.close();
        System.exit(0);
    }

    public void runDemo() throws Exception {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter username");
        String user = scanner.next();
        System.out.println("Enter pw");
        String pw = scanner.next();
        scanner.close();
        startMail(user, pw);
        Thread.sleep(10_000);
    }

    @Autowired
    private IntegrationFlowContext flowContext;

    public void startMail(String user, String pw) {
        IntegrationFlow flow = IntegrationFlows
                .from(Mail.imapIdleAdapter(imapUrl(user, pw))
                        .javaMailProperties(p -> p.put("mail.debug", "false"))
                        .userFlag("testSIUserFlag") // needed by the SI test server - not needed if server supports /SEEN
                        .headerMapper(new DefaultMailHeaderMapper()))
                .handle(System.out::println)
                .get();
        this.flowContext.registration(flow).register();
    }

    private String imapUrl(String user, String pw) {
        return "imap://"
                + user + ":" + pw
                + "@localhost:" + imapServer().getPort() + "/INBOX";
    }

    @Bean
    public TestMailServer.ImapServer imapServer() {
        return TestMailServer.imap(0);
    }

}

Maven deps:

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-integration</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-mail</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.integration</groupId>
        <artifactId>spring-integration-mail</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.integration</groupId>
        <artifactId>spring-integration-test</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.integration</groupId>
        <artifactId>spring-integration-java-dsl</artifactId>
    </dependency>