télécharger le courrier en pièce jointe avec Java

Voici la classe que j'utilise pour télécharger des e-mails (avec le traitement des pièces jointes). Vous aurez à regarder par certains des trucs qu'il fait (comme Ignorer les classes de journalisation et la base de données écrit). J'ai aussi renommé certains paquets pour en faciliter la lecture.

l'idée générale est que toutes les pièces jointes sont sauvegardées sous forme de fichiers individuels dans le système de fichiers, et chaque e-mail est sauvegardé sous forme d'enregistrement dans la base de données avec un ensemble d'enregistrements enfants qui pointent vers tous les l'attachement de chemins d'accès.

Focus sur la méthode doEMailDownload.

/**
  * Copyright (c) 2008 Steven M. Cherry
  * All rights reserved.
  */
package utils.scheduled;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.sql.Timestamp;
import java.util.Properties;
import java.util.Vector;

import javax.mail.Address;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Multipart;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.MimeBodyPart;

import glob.ActionLogicImplementation;
import glob.IOConn;
import glob.log.Log;
import logic.utils.sql.Settings;
import logic.utils.sqldo.EMail;
import logic.utils.sqldo.EMailAttach;

/**
  * This will connect to our incoming e-mail server and download any e-mails
  * that are found on the server.  The e-mails will be stored for further processing
  * in our internal database.  Attachments will be written out to separate files
  * and then referred to by the database entries.  This is intended to be  run by 
  * the scheduler every minute or so.
  *
  * @author Steven M. Cherry
  */
public class DownloadEMail implements ActionLogicImplementation {

    protected String receiving_host;
    protected String receiving_user;
    protected String receiving_pass;
    protected String receiving_protocol;
    protected boolean receiving_secure;
    protected String receiving_attachments;

    /** This will run our logic */
    public void ExecuteRequest(IOConn ioc) throws Exception {
        Log.Trace("Enter");

        Log.Debug("Executing DownloadEMail");
        ioc.initializeResponseDocument("DownloadEMail");

        // pick up our configuration from the server:
        receiving_host = Settings.getValue(ioc, "server.email.receiving.host");
        receiving_user = Settings.getValue(ioc, "server.email.receiving.username");
        receiving_pass = Settings.getValue(ioc, "server.email.receiving.password");
        receiving_protocol = Settings.getValue(ioc, "server.email.receiving.protocol");
        String tmp_secure = Settings.getValue(ioc, "server.email.receiving.secure");
        receiving_attachments = Settings.getValue(ioc, "server.email.receiving.attachments");

        // sanity check on the parameters:
        if(receiving_host == null || receiving_host.length() == 0){
            ioc.SendReturn();
            ioc.Close();
            Log.Trace("Exit");
            return; // no host defined.
        }
        if(receiving_user == null || receiving_user.length() == 0){
            ioc.SendReturn();
            ioc.Close();
            Log.Trace("Exit");
            return; // no user defined.
        }
        if(receiving_pass == null || receiving_pass.length() == 0){
            ioc.SendReturn();
            ioc.Close();
            Log.Trace("Exit");
            return; // no pass defined.
        }
        if(receiving_protocol == null || receiving_protocol.length() == 0){
            Log.Debug("EMail receiving protocol not defined, defaulting to POP");
            receiving_protocol = "POP";
        }
        if(tmp_secure == null || 
            tmp_secure.length() == 0 ||
            tmp_secure.compareToIgnoreCase("false") == 0 ||
            tmp_secure.compareToIgnoreCase("no") == 0
        ){
            receiving_secure = false;
        } else {
            receiving_secure = true;
        }
        if(receiving_attachments == null || receiving_attachments.length() == 0){
            Log.Debug("EMail receiving attachments not defined, defaulting to ./email/attachments/");
            receiving_attachments = "./email/attachments/";
        }

        // now do the real work.
        doEMailDownload(ioc);

        ioc.SendReturn();
        ioc.Close();
        Log.Trace("Exit");
    }

    protected void doEMailDownload(IOConn ioc) throws Exception {
        // Create empty properties
        Properties props = new Properties();
        // Get the session
        Session session = Session.getInstance(props, null);

        // Get the store
        Store store = session.getStore(receiving_protocol);
        store.connect(receiving_host, receiving_user, receiving_pass);

        // Get folder
        Folder folder = store.getFolder("INBOX");
        folder.open(Folder.READ_WRITE);

        try {

            // Get directory listing
            Message messages[] = folder.getMessages();

            for (int i=0; i < messages.length; i++) {
                // get the details of the message:
                EMail email = new EMail();
                email.fromaddr = messages[i].getFrom()[0].toString();
                Address[] to = messages[i].getRecipients(Message.RecipientType.TO);
                email.toaddr = "";
                for(int j = 0; j < to.length; j++){
                    email.toaddr += to[j].toString() + "; ";
                }
                Address[] cc;
                try {
                    cc = messages[i].getRecipients(Message.RecipientType.CC);
                } catch (Exception e){
                    Log.Warn("Exception retrieving CC addrs: %s", e.getLocalizedMessage());
                    cc = null;
                }
                email.cc = "";
                if(cc != null){
                    for(int j = 0; j < cc.length; j++){
                        email.cc += cc[j].toString() + "; ";
                    }
                }
                email.subject = messages[i].getSubject();
                if(messages[i].getReceivedDate() != null){
                    email.received_when = new Timestamp(messages[i].getReceivedDate().getTime());
                } else {
                    email.received_when = new Timestamp( (new java.util.Date()).getTime());
                }


                email.body = "";
                Vector<EMailAttach> vema = new Vector<EMailAttach>();
                Object content = messages[i].getContent();
                if(content instanceof java.lang.String){
                    email.body = (String)content;
                } else if(content instanceof Multipart){
                    Multipart mp = (Multipart)content;

                    for (int j=0; j < mp.getCount(); j++) {
                        Part part = mp.getBodyPart(j);

                        String disposition = part.getDisposition();

                        if (disposition == null) {
                            // Check if plain
                            MimeBodyPart mbp = (MimeBodyPart)part;
                            if (mbp.isMimeType("text/plain")) {
                                Log.Debug("Mime type is plain");
                                email.body += (String)mbp.getContent();
                            } else {
                                Log.Debug("Mime type is not plain");
                                // Special non-attachment cases here of 
                                // image/gif, text/html, ...
                                EMailAttach ema = new EMailAttach();
                                ema.name = decodeName(part.getFileName());
                                File savedir = new File(receiving_attachments);
                                savedir.mkdirs();
                                File savefile = File.createTempFile("emailattach", ".atch", savedir );
                                ema.path = savefile.getAbsolutePath();
                                ema.size = part.getSize();
                                vema.add(ema);
                                ema.size = saveFile(savefile, part);
                            }
                        } else if ((disposition != null) && 
                            (disposition.equals(Part.ATTACHMENT) || disposition.equals(Part.INLINE) ) 
                        ){
                            // Check if plain
                            MimeBodyPart mbp = (MimeBodyPart)part;
                            if (mbp.isMimeType("text/plain")) {
                                Log.Debug("Mime type is plain");
                                email.body += (String)mbp.getContent();
                            } else {
                                Log.Debug("Save file (%s)", part.getFileName() );
                                EMailAttach ema = new EMailAttach();
                                ema.name = decodeName(part.getFileName());
                                File savedir = new File(receiving_attachments);
                                savedir.mkdirs();
                                File savefile = File.createTempFile("emailattach", ".atch", savedir );
                                ema.path = savefile.getAbsolutePath();
                                ema.size = part.getSize();
                                vema.add(ema);
                                ema.size = saveFile( savefile, part);
                            }
                        }
                    }
                }

                // Insert everything into the database:
                logic.utils.sql.EMail.insertEMail(ioc, email);
                for(int j = 0; j < vema.size(); j++){
                    vema.get(j).emailid = email.id;
                    logic.utils.sql.EMail.insertEMailAttach(ioc, vema.get(j) );
                }

                // commit this message and all of it's attachments
                ioc.getDBConnection().commit();

                // Finally delete the message from the server.
                messages[i].setFlag(Flags.Flag.DELETED, true);
            }

            // Close connection 
            folder.close(true); // true tells the mail server to expunge deleted messages.
            store.close();
        } catch (Exception e){
            folder.close(true); // true tells the mail server to expunge deleted messages.
            store.close();
            throw e;
        }

    }

    protected int saveFile(File saveFile, Part part) throws Exception {

        BufferedOutputStream bos = new BufferedOutputStream( new FileOutputStream(saveFile) );

        byte[] buff = new byte[2048];
        InputStream is = part.getInputStream();
        int ret = 0, count = 0;
        while( (ret = is.read(buff)) > 0 ){
            bos.write(buff, 0, ret);
            count += ret;
        }
        bos.close();
        is.close();
        return count;
    }

    protected String decodeName( String name ) throws Exception {
        if(name == null || name.length() == 0){
            return "unknown";
        }
        String ret = java.net.URLDecoder.decode( name, "UTF-8" );

        // also check for a few other things in the string:
        ret = ret.replaceAll("=\?utf-8\?q\?", "");
        ret = ret.replaceAll("\?=", "");
        ret = ret.replaceAll("=20", " ");

        return ret;
    }

}