<?xml version="1.0"?>
<!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->
<document>
  <properties>
    <title>Examples</title>
    <author email="dev@commons.apache.org">Commons Documentation Team</author>
    <author email="quintonm@apache.org">Quinton McCombs</author>
    <revision>$Id: userguide.xml 1675561 2015-04-23 09:07:30Z tn $</revision>
  </properties>

  <body>
    <section name="A simple text email">
      <p>
        Our first example will create a basic email message to "John Doe" and
        send it through your Google Mail (GMail)  account.
      </p>
      <source>
<![CDATA[
Email email = new SimpleEmail();
email.setHostName("smtp.googlemail.com");
email.setSmtpPort(465);
email.setAuthenticator(new DefaultAuthenticator("username", "password"));
email.setSSLOnConnect(true);
email.setFrom("user@gmail.com");
email.setSubject("TestMail");
email.setMsg("This is a test mail ... :-)");
email.addTo("foo@bar.com");
email.send();
]]></source>
      <p>
        The call to setHostName("mail.myserver.com") sets the address of the
        outgoing SMTP server that will be used to send the message.  If this is
        not set, the system property "mail.host" will be used.
      </p>
    </section>
    <section name="Sending emails with attachments">
      <p>
        To add attachments to an email, you will need to use the MultiPartEmail
        class.  This class works just like SimpleEmail except that it adds
        several overloaded attach() methods to add attachments to the email.
        You can add an unlimited number of attachments either inline or
        attached.  The attachments will be MIME encoded.
      </p>
      <p>
        The simplest way to add the attachments is by using the EmailAttachment
        class to reference your attachments.
      </p>
      <p>
        In the following example, we will create an attachment for a picture.
        We will then attach the picture to the email and send it.
      </p>
      <source>
<![CDATA[
import org.apache.commons.mail.*;
...

  // Create the attachment
  EmailAttachment attachment = new EmailAttachment();
  attachment.setPath("mypictures/john.jpg");
  attachment.setDisposition(EmailAttachment.ATTACHMENT);
  attachment.setDescription("Picture of John");
  attachment.setName("John");

  // Create the email message
  MultiPartEmail email = new MultiPartEmail();
  email.setHostName("mail.myserver.com");
  email.addTo("jdoe@somewhere.org", "John Doe");
  email.setFrom("me@apache.org", "Me");
  email.setSubject("The picture");
  email.setMsg("Here is the picture you wanted");

  // add the attachment
  email.attach(attachment);

  // send the email
  email.send();
]]></source>
      <p>
        You can also use EmailAttachment to reference any valid URL for files
        that you do not have locally.  When the message is sent, the file will
        be downloaded and attached to the message automatically.
      </p>
      <p>
        The next example shows how we could have sent the apache logo
        to John instead.
      </p>
      <source>
<![CDATA[
import org.apache.commons.mail.*;
...

  // Create the attachment
  EmailAttachment attachment = new EmailAttachment();
  attachment.setURL(new URL("http://www.apache.org/images/asf_logo_wide.gif"));
  attachment.setDisposition(EmailAttachment.ATTACHMENT);
  attachment.setDescription("Apache logo");
  attachment.setName("Apache logo");

  // Create the email message
  MultiPartEmail email = new MultiPartEmail();
  email.setHostName("mail.myserver.com");
  email.addTo("jdoe@somewhere.org", "John Doe");
  email.setFrom("me@apache.org", "Me");
  email.setSubject("The logo");
  email.setMsg("Here is Apache's logo");
  
  // add the attachment
  email.attach(attachment);

  // send the email
  email.send();
]]></source>
    </section>
    <section name="Sending HTML formatted email">
      <p>
        Sending HTML formatted email is accomplished by using the HtmlEmail
        class.  This class works exactly like the MultiPartEmail class with
        additional methods to set the html content, alternative text content
        if the recipient does not support HTML email, and add inline images.
      </p>
      <p>
        In this example, we will send an email message with formatted HTML
        content with an inline image.
      </p>
      <source>
<![CDATA[
import org.apache.commons.mail.HtmlEmail;
...

  // Create the email message
  HtmlEmail email = new HtmlEmail();
  email.setHostName("mail.myserver.com");
  email.addTo("jdoe@somewhere.org", "John Doe");
  email.setFrom("me@apache.org", "Me");
  email.setSubject("Test email with inline image");
  
  // embed the image and get the content id
  URL url = new URL("http://www.apache.org/images/asf_logo_wide.gif");
  String cid = email.embed(url, "Apache logo");
  
  // set the html message
  email.setHtmlMsg("<html>The apache logo - <img src=\"cid:"+cid+"\"></html>");

  // set the alternative message
  email.setTextMsg("Your email client does not support HTML messages");

  // send the email
  email.send();
]]></source>
      <p>
        First, notice that the call to embed() returns a String.  This String
        is a randomly generated identifier that must be used to reference
        the image in the image tag.
      </p>
      <p>
        Next, there was no call to setMsg() in this example.  The method is
        still available in HtmlEmail but it should not be used if you will be
        using inline images.  Instead, the setHtmlMsg() and setTextMsg()
        methods were used.
      </p>
    </section>
    <section name="Sending HTML formatted email with embedded images">
      <p>
        The previous example showed how to create a HTML email with embedded
        images but you need to know all images upfront which is inconvenient
        when using a HTML email template. The ImageHtmlEmail helps you
        solving this problem by converting all external images to inline
        images.
      </p>        
      <source>
        <![CDATA[
import org.apache.commons.mail.HtmlEmail;
...

  // load your HTML email template
  String htmlEmailTemplate = ".... <img src=\"http://www.apache.org/images/feather.gif\"> ....";

  // define you base URL to resolve relative resource locations
  URL url = new URL("http://www.apache.org");

  // create the email message
  ImageHtmlEmail email = new ImageHtmlEmail();
  email.setDataSourceResolver(new DataSourceUrlResolver(url));
  email.setHostName("mail.myserver.com");
  email.addTo("jdoe@somewhere.org", "John Doe");
  email.setFrom("me@apache.org", "Me");
  email.setSubject("Test email with inline image");
  
  // set the html message
  email.setHtmlMsg(htmlEmailTemplate);

  // set the alternative message
  email.setTextMsg("Your email client does not support HTML messages");

  // send the email
  email.send();
  ]]></source>        
      <p>
        First we create a HTML email template referencing some images. All  
        referenced images are automatically transformed to inline images by
        the specified DataSourceResolver.
      </p>
    </section>  
    <section name="Debugging">
      <p>
        The JavaMail API supports a debugging option that will can be very
        useful if you run into problems.  You can activate debugging on any
        of the mail classes by calling setDebug(true).  The debugging output
        will be written to <code>System.out</code>.
      </p>
      <p>
        Sometimes you want to experiment with various security setting or
        features of commons-email. A good starting point is the test class
        <code>EmailLiveTest</code> and <code>EmailConfiguration</code> which
        are used for testing commons-email with real SMTP servers.
      </p>      
    </section>
    <section name="Authentication">
      <p>
        If you need to authenticate to your SMTP server, you can call the
        <code>setAuthentication(userName,password)</code> method before sending
        your email.  This will create an instance of
        <code>DefaultAuthenticator</code> which will be used by the JavaMail
        API when the email is sent.  Your server must support RFC2554 in
        order for this to work.
      </p>
      <p>
        You can perform a more complex authentication method such as displaying
        a dialog box to the user by creating a subclass of the
        <code>javax.mail.Authenticator</code> object.  You will need to
        override the <code>getPasswordAuthentication()</code> method where
        you will handle collecting the user's information.  To make use of
        your new <code>Authenticator</code> class, use the
        <code>Email.setAuthenticator</code> method.
      </p>
    </section>
    <section name="Security">
      <p>
        Nowadays you should not use plain SMTP protocol when using public SMTP servers 
        but there is a some confusion regarding the available options.
      </p>
      <p>  
        Two commons options are using 
        <ul>
          <li>STARTTLS on port 25</li>
          <li>SSL on port 465</li>
        </ul>
        The following definitions were taken from Wikipedia
        <ul>
          <li>
            STARTTLS is an extension to plain text communication protocols, which offers a 
            way to upgrade a plain text connection to an encrypted (TLS or SSL) connection 
            instead of using a separate port for encrypted communication.
          </li>
          <li>
            Transport Layer Security (TLS) and its predecessor, Secure Sockets Layer (SSL), 
            are cryptographic protocols that provide communication security over the 
            Internet.TLS and SSL encrypt the segments of network connections above the 
            Transport Layer, using asymmetric cryptography for key exchange, symmetric 
            encryption for privacy, and message authentication codes for message integrity.
          </li>
        </ul>
        In addition you can force the following security checks (which are disabled by default)
        <ul>
          <li>
            When using a secured transport (STARTTLS or SSL) you can force validating the server's 
            certificate by calling <code>Email.setSSLCheckServerIdentity(true)</code>.  
          </li>
          <li>
            Enforce using STARTTLS by calling <code>Email.setStartTLSRequired(true)</code>
          </li>
        </ul>
      </p>
    </section>
    <section name="Handling Bounced Messages">
      <p>
        Normally, messages which cannot be delivered to a recipient are returned to the
        sender (specified with the <code>from</code> property).  However, in some cases,
        you'll want these to be sent to a different address.  To do this, simply call the
        <code>setBounceAddress(emailAddressString)</code> method before sending
        your email.
      </p>
      <p>
        Technical notes: When SMTP servers cannot deliver mail, they do not pay any attention
        to the contents of the message to determine where the error notification should be
        sent.  Rather, they refer to the SMTP "envelope sender" value.  JavaMail sets this
        value according to the value of the <code>mail.smtp.from</code> property on the
        JavaMail <code>Session</code>.  (Commons Email initializes the JavaMail
        <code>Session</code> using <code>System.getProperties()</code>)
        If this property has not been set, then JavaMail
        uses the "from" address.  If your email bean has the <code>bounceAddress</code>
        property set, then Commons Email uses it to set the value of <code>mail.smtp.from</code>
        when the <code>Session</code> is initialized, overriding any other value
        which might have been set.
      </p>
      <p>
        <em>Note: </em> This is the only way to control the handling of bounced email.
        Specifically, the "Errors-to:" SMTP header is deprecated and cannot be trusted
        to control how a bounced message will be handled.  Also note that it is considered bad
        practice to send email with an untrusted "from" address unless you also set the
        bounce address.  If your application allows users to enter an address which is used
        as the "from" address on an email, you should be sure to set the bounce address
        to a known good address.
      </p>
    </section>
  </body>
</document>



