Java tutorial
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See the License for the * * specific language governing permissions and limitations * * under the License. * ****************************************************************/ package org.apache.james.transport.mailets; import java.io.UnsupportedEncodingException; import java.util.Collection; import javax.mail.MessagingException; import javax.mail.internet.AddressException; import javax.mail.internet.MimeMessage; import javax.mail.internet.MimeUtility; import org.apache.james.mime4j.dom.address.Address; import org.apache.james.mime4j.dom.address.AddressList; import org.apache.james.mime4j.dom.address.Group; import org.apache.james.mime4j.dom.address.Mailbox; import org.apache.james.mime4j.field.address.LenientAddressParser; import org.apache.james.mime4j.util.MimeUtil; import org.apache.mailet.Experimental; import org.apache.mailet.Mail; import org.apache.mailet.MailAddress; import org.apache.mailet.base.GenericMailet; import com.google.common.base.Function; import com.google.common.base.Splitter; import com.google.common.base.Throwables; import com.google.common.collect.FluentIterable; import com.google.common.collect.ImmutableList; /** * <p>Mailet designed to process the recipients from the mail headers rather * than the recipients specified in the SMTP message header. This can be * useful if your mail is redirected on-route by a mail server that * substitutes a fixed recipient address for the original.</p> * <p/> * <p>To use this, match against the redirection address using the * <code>RecipientIs</code> matcher and set the mailet 'class' to * <code>UseHeaderRecipients</code>. This will cause the email to be * re-injected into the root process with the recipient substituted * by all the recipients in the Mail-For, To and Cc headers * of the message.</p> * <p/> * <p>e.g.</p> * <pre><code> * <mailet match="RecipientIs=forwarded@myhost" * class="UseHeaderRecipients"> * </mailet> * </code></pre> * * @version 1.0.0, 24/11/2000 */ @Experimental public class UseHeaderRecipients extends GenericMailet { public static final Function<Mailbox, MailAddress> TO_MAIL_ADDRESS = new Function<Mailbox, MailAddress>() { @Override public MailAddress apply(Mailbox input) { try { return new MailAddress(input.getAddress()); } catch (AddressException e) { throw Throwables.propagate(e); } } }; /** * Controls certain log messages */ private boolean isDebug = false; /** * Initialize the mailet * <p/> * initializes the DEBUG flag */ public void init() { isDebug = (getInitParameter("debug") == null) ? false : Boolean.valueOf(getInitParameter("debug")); } /** * Process an incoming email, removing the currently identified * recipients and replacing them with the recipients indicated in * the Mail-For, To and Cc headers of the actual email. * * @param mail incoming email */ public void service(Mail mail) throws MessagingException { MimeMessage message = mail.getMessage(); mail.setRecipients(headersAddresses(message)); if (isDebug) { log("All recipients = " + mail.getRecipients()); log("Reprocessing mail using recipients in message headers"); } // Return email to the "root" process. getMailetContext().sendMail(mail.getSender(), mail.getRecipients(), mail.getMessage()); mail.setState(Mail.GHOST); } public Collection<MailAddress> headersAddresses(MimeMessage mimeMessage) throws MessagingException { Collection<MailAddress> mailForHeaderAddresses = getHeaderMailAddresses(mimeMessage, "Mail-For"); if (!mailForHeaderAddresses.isEmpty()) { return mailForHeaderAddresses; } return ImmutableList.<MailAddress>builder().addAll(getHeaderMailAddresses(mimeMessage, "To")) .addAll(getHeaderMailAddresses(mimeMessage, "Cc")) .addAll(getHeaderMailAddresses(mimeMessage, "Bcc")).build(); } /** * Return a string describing this mailet. * * @return a string describing this mailet */ public String getMailetInfo() { return "UseHeaderRecipients Mailet"; } /** * Work through all the headers of the email with a matching name and * extract all the mail addresses as a collection of addresses. * * @param message the mail message to read * @param name the header name as a String * @return the collection of MailAddress objects. */ private Collection<MailAddress> getHeaderMailAddresses(MimeMessage message, String name) throws MessagingException { if (isDebug) { log("Checking " + name + " headers"); } String[] headers = message.getHeader(name); ImmutableList.Builder<MailAddress> addresses = ImmutableList.builder(); if (headers != null) { for (String header : headers) { addresses.addAll(getMailAddressesFromHeaderLine(header)); } } return addresses.build(); } private ImmutableList<MailAddress> getMailAddressesFromHeaderLine(String header) throws MessagingException { String unfoldedDecodedString = sanitizeHeaderString(header); Iterable<String> headerParts = Splitter.on(",").split(unfoldedDecodedString); return getMailAddressesFromHeadersParts(headerParts); } private ImmutableList<MailAddress> getMailAddressesFromHeadersParts(Iterable<String> headerParts) throws AddressException { ImmutableList.Builder<MailAddress> result = ImmutableList.builder(); for (String headerPart : headerParts) { if (isDebug) { log("Address = " + headerPart); } result.addAll(readMailAddresses(headerPart)); } return result.build(); } private Collection<MailAddress> readMailAddresses(String headerPart) throws AddressException { AddressList addressList = LenientAddressParser.DEFAULT.parseAddressList(MimeUtil.unfold(headerPart)); ImmutableList.Builder<Mailbox> mailboxList = ImmutableList.builder(); for (Address address : addressList) { mailboxList.addAll(convertAddressToMailboxCollection(address)); } return FluentIterable.from(mailboxList.build()).transform(TO_MAIL_ADDRESS).toList(); } private Collection<Mailbox> convertAddressToMailboxCollection(Address address) { if (address instanceof Mailbox) { return ImmutableList.of((Mailbox) address); } else if (address instanceof Group) { return ImmutableList.copyOf(((Group) address).getMailboxes()); } return ImmutableList.of(); } private String sanitizeHeaderString(String header) throws MessagingException { try { return MimeUtility.unfold(MimeUtility.decodeText(header)); } catch (UnsupportedEncodingException e) { throw new MessagingException("Can not decode header", e); } } }