Changed defaults for downloadMessageBody and downloadOnlyPlainTextOrHtmlMessageBody

README.md

@@ -22,14 +22,18 @@ val invoiceFromXml = reader.extractFromXml(File("XRechnung.xml"))
 ### Find all invoices of an IMAP email account
 
 ```kotlin
-val mailReader = MailReader()
+val emailsFetcher = EmailsFetcher()
 
-val mailsWithEInvoices = mailReader.listAllMessagesWithEInvoice(MailAccount(
-    username = "", // your mail account username
-    password = "", // your mail account username
+val fetchResult = emailsFetcher.fetchAllEmails(EmailAccount(
+    username = "", // your email account username
+    password = "", // your email account username
     serverAddress = "", // IMAP server address
-    port = null // IMAP server port, leave null if default port 993
+    port = null // IMAP server port, can be left null for default port 993
 ))
+
+fetchResult.emails.forEach { email ->
+    println("${email.sender}: ${email.attachments.firstNotNullOfOrNull { it.invoice }?.totalAmounts?.duePayableAmount}")
+}
 ```
 
 ### Validate eInvoice
@@ -54,7 +58,7 @@ fun create() {
     val creator = EInvoiceCreator()
 
     // create a PDF that also contains the eInvoice as XML attachment
-    creator.createFacturXPdf(invoice, pdfResultFile)
+    creator.createPdfWithAttachedXml(invoice, pdfResultFile)
 
     // create only the XML file
     val xml = creator.createFacturXXml(invoice)
@@ -84,7 +88,7 @@ val creator = EInvoiceCreator()
 creator.attachInvoiceXmlToPdf(invoice, existingPdf, output)
 
 // or if you already have the invoice XML:
-val invoiceXml: String = "..." // e.g. creator.createZugferdXml(invoice)
+val invoiceXml = creator.createXRechnungXml(invoice) // or creator.createZugferdXml(invoice), ...
 
-creator.attachInvoiceXmlToPdf(invoiceXml, existingPdf, output)
+creator.attachInvoiceXmlToPdf(invoiceXml, EInvoiceXmlFormat.XRechnung, existingPdf, output)
 ```

e-invoice-api/src/main/kotlin/net/codinux/invoicing/service/InvoicingService.kt

@@ -27,7 +27,7 @@ class InvoicingService {
     fun createFacturXPdf(invoice: Invoice): Path {
         val resultFile = createTempPdfFile()
 
-        creator.createFacturXPdf(invoice, resultFile.toFile())
+        creator.createPdfWithAttachedXml(invoice, resultFile.toFile())
 
         return resultFile
     }

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/converter/EInvoiceConverter.kt

@@ -65,8 +65,10 @@ open class EInvoiceConverter {
     protected open fun createXRechnungXml(invoice: Invoice): String = EInvoiceCreator().createXRechnungXml(invoice)
 
     protected open fun copyResource(resourceName: String, outputFile: File, outputFileExtension: String) {
-        javaClass.classLoader.getResourceAsStream(resourceName).use {
-            it?.copyTo(File(outputFile.parentFile, outputFile.nameWithoutExtension + outputFileExtension).outputStream())
+        javaClass.classLoader.getResourceAsStream(resourceName).use { inputStream ->
+            File(outputFile.parentFile, outputFile.nameWithoutExtension + outputFileExtension).outputStream().use { outputStream ->
+                inputStream?.copyTo(outputStream)
+            }
         }
     }
 

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/creation/EInvoiceCreator.kt

@@ -1,73 +1,33 @@
 package net.codinux.invoicing.creation
 
 import net.codinux.invoicing.mapper.MustangMapper
+import net.codinux.invoicing.model.EInvoiceXmlFormat
 import net.codinux.invoicing.model.Invoice
 import org.mustangproject.ZUGFeRD.*
 import java.io.File
+import java.io.InputStream
+import java.io.OutputStream
 
 open class EInvoiceCreator(
     protected open val mapper: MustangMapper = MustangMapper()
 ) {
 
-    open fun createXRechnungXml(invoice: Invoice): String {
-        val provider = ZUGFeRD2PullProvider()
-        provider.profile = Profiles.getByName("XRechnung")
-
-        return createXml(provider, invoice)
-    }
-
+    open fun createXRechnungXml(invoice: Invoice) = createXml(invoice, EInvoiceXmlFormat.XRechnung)
 
     /**
      * Synonym for [createFacturXXml] (ZUGFeRD 2 is a synonym for Factur-X).
      */
     open fun createZugferdXml(invoice: Invoice) = createFacturXXml(invoice)
 
-    open fun createFacturXXml(invoice: Invoice): String {
+    open fun createFacturXXml(invoice: Invoice) = createXml(invoice, EInvoiceXmlFormat.FacturX)
+
+    protected open fun createXml(invoice: Invoice, format: EInvoiceXmlFormat): String {
         val exporter = ZUGFeRDExporterFromA3()
-            .setProfile("EN16931") // required for XML?
+            .setProfile(getProfileNameForFormat(format))
 
         return createXml(exporter.provider, invoice)
     }
 
-    /**
-     * Synonym for [createFacturXPdf] (ZUGFeRD 2 is a synonym for Factur-X).
-     */
-    open fun createZugferdPdf(invoice: Invoice, outputFile: File) = createFacturXPdf(invoice, outputFile)
-
-    open fun createFacturXPdf(invoice: Invoice, outputFile: File) {
-        val xml = createFacturXXml(invoice)
-        val xmlFile = File.createTempFile(outputFile.nameWithoutExtension, ".xml")
-            .also { it.writeText(xml) }
-        val pdfFile = File(xmlFile.parentFile, xmlFile.nameWithoutExtension + ".pdf")
-
-        val visualizer = ZUGFeRDVisualizer()
-        visualizer.toPDF(xmlFile.absolutePath, pdfFile.absolutePath)
-
-        attachInvoiceXmlToPdf(xml, pdfFile, outputFile)
-
-        xmlFile.delete()
-        pdfFile.delete()
-    }
-
-
-    open fun attachInvoiceXmlToPdf(invoice: Invoice, pdfFile: File, outputFile: File) =
-        attachInvoiceXmlToPdf(createFacturXXml(invoice), pdfFile, outputFile)
-
-    open fun attachInvoiceXmlToPdf(invoiceXml: String, pdfFile: File, outputFile: File) {
-        val exporter = ZUGFeRDExporterFromA3()
-            .setZUGFeRDVersion(2)
-            .setProfile("EN16931") // available values: MINIMUM, BASICWL, BASIC, CIUS, EN16931, EXTENDED, XRECHNUNG
-//            .disableFacturX()
-            .setProducer("danki die geile Sau")
-            .setCreator(System.getProperty("user.name"))
-
-        exporter.load(pdfFile.inputStream())
-        exporter.setXML(invoiceXml.toByteArray())
-
-        exporter.export(outputFile.outputStream())
-    }
-
-
     protected open fun createXml(provider: IXMLProvider, invoice: Invoice): String {
         val transaction = mapper.mapToTransaction(invoice)
 
@@ -76,4 +36,80 @@ open class EInvoiceCreator(
         return String(provider.xml, Charsets.UTF_8)
     }
 
+
+    /**
+     * Creates a hybrid PDF that also contains the Factur-X / ZUGFeRD or XRechnung XML as attachment.
+     */
+    @JvmOverloads
+    open fun createPdfWithAttachedXml(invoice: Invoice, outputFile: File, format: EInvoiceXmlFormat = EInvoiceXmlFormat.FacturX) {
+        val xml = createXml(invoice, format)
+
+        createPdfWithAttachedXml(xml, format, outputFile)
+    }
+
+    open fun createPdfWithAttachedXml(invoiceXml: String, format: EInvoiceXmlFormat, outputFile: File) {
+        outputFile.outputStream().use { outputStream ->
+            createPdfWithAttachedXml(invoiceXml, format, outputStream)
+        }
+    }
+
+    open fun createPdfWithAttachedXml(invoiceXml: String, format: EInvoiceXmlFormat, outputFile: OutputStream) {
+        val xmlFile = File.createTempFile("${format.name}-invoice", ".xml")
+            .also { it.writeText(invoiceXml) }
+        val pdfFile = File(xmlFile.parentFile, xmlFile.nameWithoutExtension + ".pdf")
+
+        val visualizer = ZUGFeRDVisualizer()
+        visualizer.toPDF(xmlFile.absolutePath, pdfFile.absolutePath)
+
+        pdfFile.inputStream().use { inputStream ->
+            attachInvoiceXmlToPdf(invoiceXml, format, inputStream, outputFile)
+        }
+
+        xmlFile.delete()
+        pdfFile.delete()
+    }
+
+
+    @JvmOverloads
+    open fun attachInvoiceXmlToPdf(invoice: Invoice, pdfFile: File, outputFile: File, format: EInvoiceXmlFormat = EInvoiceXmlFormat.FacturX) =
+        attachInvoiceXmlToPdf(createXml(invoice, format), format, pdfFile, outputFile)
+
+    open fun attachInvoiceXmlToPdf(invoiceXml: String, format: EInvoiceXmlFormat, pdfFile: File, outputFile: File) {
+        pdfFile.inputStream().use { inputStream ->
+            outputFile.outputStream().use { outputStream ->
+                attachInvoiceXmlToPdf(invoiceXml, format, inputStream, outputStream)
+            }
+        }
+    }
+
+    open fun attachInvoiceXmlToPdf(invoiceXml: String, format: EInvoiceXmlFormat, pdfFile: InputStream, outputFile: OutputStream) =
+        attachInvoiceXmlToPdf(invoiceXml, format, pdfFile.readAllBytes(), outputFile)
+
+    open fun attachInvoiceXmlToPdf(invoiceXml: String, format: EInvoiceXmlFormat, pdfFile: ByteArray, outputFile: OutputStream) {
+        val exporter = ZUGFeRDExporterFromA3()
+            .setZUGFeRDVersion(2)
+            .setProfile(getProfileNameForFormat(format))
+//            .disableFacturX()
+            .setProducer("danki die geile Sau")
+            .setCreator(System.getProperty("user.name"))
+            .setCreatorTool("Unglaublich geiles eInvoicing Tool von codinux")
+
+        exporter.load(pdfFile)
+        exporter.setXML(invoiceXml.toByteArray())
+
+        exporter.export(outputFile)
+    }
+
+
+    protected open fun getProfileNameForFormat(format: EInvoiceXmlFormat) = when (format) {
+        EInvoiceXmlFormat.FacturX -> "EN16931" // available values: MINIMUM, BASICWL, BASIC, CIUS, EN16931, EXTENDED, XRECHNUNG
+        EInvoiceXmlFormat.XRechnung -> "XRECHNUNG"
+    }
+
+    protected open fun getFilenameForFormat(format: EInvoiceXmlFormat) = when (format) {
+        EInvoiceXmlFormat.FacturX -> "factur-x.xml"
+        EInvoiceXmlFormat.XRechnung -> "xrechnung.xml"
+        // other available values: "zugferd-invoice.xml" (ZF v2), "ZUGFeRD-invoice.xml" (ZF v1) ("order-x.xml", "cida.xml")
+    }
+
 }

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/EmailsFetcher.kt

@@ -0,0 +1,357 @@
+package net.codinux.invoicing.email
+
+import jakarta.mail.*
+import jakarta.mail.event.MessageCountAdapter
+import jakarta.mail.event.MessageCountEvent
+import jakarta.mail.internet.InternetAddress
+import jakarta.mail.internet.MimeUtility
+import kotlinx.coroutines.*
+import net.codinux.invoicing.email.model.*
+import net.codinux.invoicing.filesystem.FileUtil
+import net.codinux.invoicing.model.Invoice
+import net.codinux.invoicing.reader.EInvoiceReader
+import net.codinux.log.logger
+import org.eclipse.angus.mail.imap.IMAPFolder
+import org.eclipse.angus.mail.imap.IMAPMessage
+import java.io.File
+import java.time.Instant
+import java.util.*
+import java.util.concurrent.Executors
+import kotlin.math.max
+
+open class EmailsFetcher(
+    protected open val eInvoiceReader: EInvoiceReader = EInvoiceReader(),
+    protected open val coroutineDispatcher: CoroutineDispatcher = Executors.newFixedThreadPool(max(24, Runtime.getRuntime().availableProcessors() * 4)).asCoroutineDispatcher()
+) {
+
+    protected data class MessagePart(
+        val mediaType: String,
+        val part: Part
+    )
+
+
+    companion object {
+        protected val MessageBodyMediaTypes = listOf("text/plain", "text/html")
+
+        protected val FileNotDownloadedOrErrorOccurred = Pair<Invoice?, File?>(null, null)
+    }
+
+
+    protected val log by logger()
+
+
+    open fun listenForNewEmails(account: EmailAccount, options: ListenForNewMailsOptions) = runBlocking {
+        try {
+            connect(account, options) { store ->
+                val folder = store.getFolder(options.emailFolderName) as IMAPFolder
+                folder.open(Folder.READ_ONLY)
+
+                val status = FetchEmailsStatus(account, folder, options)
+
+                folder.addMessageCountListener(object : MessageCountAdapter() {
+                    override fun messagesAdded(event: MessageCountEvent) {
+                        event.messages.forEach { message ->
+                            getEmail(message, status)
+                        }
+                    }
+                })
+
+                launch(coroutineDispatcher) {
+                    keepConnectionOpen(status, folder, options)
+                }
+            }
+        } catch (e: Throwable) {
+            log.error(e) { "Listening to new emails of '${account.username}' failed" }
+            options.onError?.invoke(FetchEmailError(FetchEmailErrorType.ListenForNewEmails, null, e))
+        }
+    }
+
+    protected open suspend fun keepConnectionOpen(status: FetchEmailsStatus, folder: IMAPFolder, options: ListenForNewMailsOptions) {
+        val account = status.account
+        log.info { "Listening to new emails of $account" }
+
+        // Use IMAP IDLE to keep the connection alive
+        while (options.stopListening.get() == false) {
+            if (!folder.isOpen) {
+                log.info { "Reopening inbox of $account ..." }
+                folder.open(Folder.READ_ONLY)
+            }
+
+            folder.idle()
+
+            delay(250)
+        }
+
+        log.info { "Stopped listening to new emails of '$account}'" }
+    }
+
+
+    open fun fetchAllEmails(account: EmailAccount, options: FetchEmailsOptions = FetchEmailsOptions()): FetchEmailsResult {
+        try {
+            return connect(account, options) { store ->
+                val folder = store.getFolder(options.emailFolderName) as IMAPFolder
+                folder.open(Folder.READ_ONLY)
+
+                val status = FetchEmailsStatus(account, folder, options)
+
+                val emails = fetchAllEmailsInFolder(status).also {
+                    folder.close(false)
+                }
+
+                FetchEmailsResult(emails, null, status.messageSpecificErrors)
+            }
+        } catch (e: Throwable) {
+            log.error(e) { "Could not fetch emails of account $account" }
+
+            return FetchEmailsResult(emptyList(), e)
+        }
+    }
+
+    protected open fun fetchAllEmailsInFolder(status: FetchEmailsStatus): List<Email> = runBlocking {
+        val folder = status.folder
+        val messageCount = folder.messageCount
+        if (messageCount <= 0) {
+            return@runBlocking emptyList()
+        }
+
+        val startUid = (status.options.lastRetrievedMessageId ?: 0) + 1 // message numbers start at 1
+        val messages = folder.getMessagesByUID(startUid, UIDFolder.MAXUID)
+
+        // for each data type like envelope (from, subject, ...), body structure, if message is unread, ... a network request is
+        // executed, making the overall process very slow -> use FetchProfile to prefetch requested data with a single request
+        folder.fetch(messages, getFetchProfile(status))
+
+        messages.mapNotNull { message ->
+            async(coroutineDispatcher) {
+                try {
+                    getEmail(message, status)
+                } catch (e: Throwable) {
+                    log.error(e) { "Could not get email $message" }
+                    status.addError(FetchEmailErrorType.GetEmail, folder.getUID(message), e)
+                    null
+                }
+            }
+        }
+            .awaitAll()
+            .filterNotNull()
+    }
+
+    private fun getFetchProfile(status: FetchEmailsStatus) = FetchProfile().apply {
+        add(UIDFolder.FetchProfileItem.UID) // message UID
+        add(FetchProfile.Item.ENVELOPE) // from, subject, to, ...
+        add(FetchProfile.Item.CONTENT_INFO) // content type, disposition, ...
+
+        // add(FetchProfile.Item.FLAGS) // message status like unread, deleted, draft, ...
+        // add(IMAPFolder.FetchProfileItem.MESSAGE) // the entire message including all attachments, headers, ... there should be rarely a use case for it
+    }
+
+    protected open fun getEmail(message: Message, status: FetchEmailsStatus): Email? {
+        val date = map(message.sentDate ?: message.receivedDate)
+        status.options.minMessageDate?.let { minDate ->
+            if (date.isBefore(minDate)) {
+                log.debug { "Ignoring message $message with date $date as it is before downloadOnlyMessagesNewerThan date $minDate" }
+                return null
+            }
+        }
+
+
+        val imapMessage = message as? IMAPMessage
+        val messageId = status.folder.getUID(message)
+
+        val parts = getAllMessageParts(message)
+        val messageBodyParts = parts.filter { it.part.fileName == null && it.mediaType in MessageBodyMediaTypes }
+        val attachmentParts = parts.filter { it !in messageBodyParts }
+
+        val attachments = attachmentParts.mapNotNull { part ->
+            getAttachment(part, status, messageId)
+        }
+
+        val sender = message.from?.firstOrNull()?.let { map(it) }
+        val plainTextBody = getPlainTextBody(messageBodyParts, status, messageId)
+
+        val email = Email(
+            messageId,
+            sender, message.subject ?: "", date,
+
+            message.getRecipients(Message.RecipientType.TO).orEmpty().map { map(it) }, message.getRecipients(Message.RecipientType.CC).orEmpty().map { map(it) }, message.getRecipients(Message.RecipientType.BCC).orEmpty().map { map(it) },
+            (message.replyTo?.firstOrNull() as? InternetAddress)?.let { if (it.address != sender?.address) map(it) else null }, // only set replyTo if it differs from sender
+
+            plainTextBody, getHtmlBody(messageBodyParts, status, messageId, plainTextBody),
+
+            imapMessage?.contentLanguage?.firstOrNull(),
+            parts.any { it.mediaType == "application/pgp-encrypted" },
+
+            attachments
+        )
+
+        status.options.emailReceived(email)
+
+        return email
+    }
+
+    protected open fun map(address: Address): EmailAddress =
+        if (address is InternetAddress) { // use MimeUtility to parse e.g. Quoted-printable names that e.g. start with "=?UTF-8?Q?"
+            EmailAddress(address.address, address.personal?.let { MimeUtility.decodeText(it) })
+        } else {
+            EmailAddress(address.toString())
+        }
+
+    protected open fun getAttachment(messagePart: MessagePart, status: FetchEmailsStatus, messageId: Long): EmailAttachment? {
+        try {
+            val part = messagePart.part
+            if (part.fileName == null) { // not an attachment
+                return null
+            }
+
+            val filename = File(part.fileName)
+            val extension = filename.extension.lowercase()
+
+            val (invoice, invoiceFile) = tryToReadEInvoice(part, extension, messagePart.mediaType, status)
+
+            if (invoice != null || Part.ATTACHMENT.equals(part.disposition, ignoreCase = true)) {
+                val file = invoiceFile ?:
+                            if (extension !in status.options.downloadAttachmentsWithExtensions) null
+                            else downloadAttachment(part, status)
+
+                return EmailAttachment(part.fileName, extension, part.size.takeIf { it > 0 }, mapDisposition(part), messagePart.mediaType, part.contentType, invoice, file)
+            }
+        } catch (e: Throwable) {
+            log.error(e) { "Could not check attachment '${messagePart.part.fileName}' (${messagePart.mediaType}) for eInvoice" }
+            status.addError(FetchEmailErrorType.GetAttachment, messageId, e)
+        }
+
+        return null
+    }
+
+    private fun mapDisposition(part: Part) = when (part.disposition?.lowercase()) {
+        "inline" -> ContentDisposition.Inline
+        "attachment" -> ContentDisposition.Attachment
+        null -> ContentDisposition.Body
+        else -> ContentDisposition.Unknown
+    }
+
+    protected open fun tryToReadEInvoice(part: Part, extension: String, mediaType: String?, status: FetchEmailsStatus): Pair<Invoice?, File?> =
+        if (extension == "pdf" || mediaType == "application/pdf" || mediaType == "application/octet-stream") {
+            val file = downloadAttachment(part, status)
+            Pair(eInvoiceReader.extractFromPdfOrNull(part.inputStream), file)
+        } else if (extension == "xml" || mediaType == "application/xml" || mediaType == "text/xml") {
+            val file = downloadAttachment(part, status)
+            Pair(eInvoiceReader.extractFromXmlOrNull(part.inputStream), file)
+        } else {
+            FileNotDownloadedOrErrorOccurred
+        }
+
+    private fun downloadAttachment(part: Part, status: FetchEmailsStatus) =
+        File(status.userAttachmentsDownloadDirectory, FileUtil.removeIllegalFileCharacters(part.fileName)).also { file ->
+            part.inputStream.use { inputStream ->
+                file.outputStream().use { outputStream ->
+                    inputStream.copyTo(outputStream)
+                }
+            }
+        }
+
+
+    protected open fun getAllMessageParts(part: Part): List<MessagePart> {
+        return if (part.isMimeType("multipart/*")) {
+            val multipart = part.content as Multipart
+            val parts = IntRange(0, multipart.count - 1).map { multipart.getBodyPart(it) }
+
+            parts.flatMap { subPart ->
+                getAllMessageParts(subPart)
+            }
+        } else {
+            val mediaType = getMediaType(part)
+            if (mediaType == null) {
+                log.warn { "Could not determine media type of message part $part" }
+                emptyList()
+            } else {
+                listOf(MessagePart(mediaType, part))
+            }
+        }
+    }
+
+    /**
+     * In most cases parameters are added to content-type's media type, e.g.
+     * - text/html; charset=utf-8
+     * - multipart/related; boundary="boundary-related"; type="text/html"
+     *
+     * -> This method removes parameters and return media type (first part) only
+     */
+    protected open fun getMediaType(part: Part): String? = part.contentType?.lowercase()?.let { contentType ->
+        val indexOfSeparator = contentType.indexOf(';')
+
+        if (indexOfSeparator > -1) {
+            contentType.substring(0, indexOfSeparator)
+        } else {
+            contentType
+        }
+    }
+
+    protected open fun getPlainTextBody(parts: Collection<MessagePart>, status: FetchEmailsStatus, messageId: Long) =
+        if (status.options.downloadMessageBody) getBodyWithMediaType(parts, "text/plain", status, messageId) else null
+
+    protected open fun getHtmlBody(parts: Collection<MessagePart>, status: FetchEmailsStatus, messageId: Long, plainTextBody: String?) =
+        // in case of downloadOnlyPlainTextOrHtmlMessageBody == true, download html body only if there's no plain text body
+        if (status.options.downloadMessageBody && (status.options.downloadOnlyPlainTextOrHtmlMessageBody == false || plainTextBody == null)) {
+            getBodyWithMediaType(parts, "text/html", status, messageId)
+        } else {
+            null
+        }
+
+    protected open fun getBodyWithMediaType(parts: Collection<MessagePart>, mediaType: String, status: FetchEmailsStatus, messageId: Long): String? = try {
+        val partsForMediaType = parts.filter { it.mediaType == mediaType }
+
+        if (partsForMediaType.size == 1) {
+            partsForMediaType.first().part.content as? String
+        } else if (partsForMediaType.isEmpty()) {
+            null
+        } else {
+            val partsForMediaTypeWithoutFilename = partsForMediaType.filter { it.part.fileName == null }
+            if (partsForMediaTypeWithoutFilename.size == 1) {
+                partsForMediaTypeWithoutFilename.first().part.content as? String
+            } else if (partsForMediaTypeWithoutFilename.isEmpty()) {
+                log.warn { "Multiple message parts with media type '$mediaType' found, but all have a filename" }
+                null
+            } else { // if there are multiple parts without filename, then the second one is in most cases quoted previous message(s)
+                partsForMediaTypeWithoutFilename.mapNotNull { it.part.content as? String }.joinToString("\r\n")
+            }
+        }
+    } catch (e: Throwable) {
+        log.error(e) { "Could not get message body for media type '$mediaType'" }
+        status.addError(FetchEmailErrorType.GetMesssageBody, messageId, e)
+        null
+    }
+
+    protected open fun map(date: Date): Instant =
+        date.toInstant()
+
+
+    protected open fun <T> connect(account: EmailAccount, options: FetchEmailsOptions, connected: (Store) -> T): T {
+        val properties = mapAccountToJavaMailProperties(account, options)
+
+        val session = Session.getInstance(properties)
+        session.getStore("imap").use { store ->
+            store.connect(account.serverAddress, account.username, account.password)
+
+            return connected(store)
+        }
+    }
+
+    protected open fun mapAccountToJavaMailProperties(account: EmailAccount, options: FetchEmailsOptions) = Properties().apply {
+        // the documentation of all properties can be found here: https://javaee.github.io/javamail/docs/api/com/sun/mail/imap/package-summary.html
+        put("mail.store.protocol", "imap")
+
+        put("mail.imap.host", account.serverAddress)
+        put("mail.imap.port", account.port?.toString() ?: "993")  // Default IMAP over SSL
+        put("mail.imap.ssl.enable", "true")
+
+        val timeout = (options.connectTimeoutSeconds * 1000).toString()
+        put("mail.imap.connectiontimeout", timeout)
+        put("mail.imap.timeout", timeout)
+
+        // speeds up fetching data tremendously
+        put("mail.imap.fetchsize", "819200") // Partial fetch size in bytes. Defaults to 16K.
+        put("mail.imap.partialfetch", "false") // Controls whether the IMAP partial-fetch capability should be used. Defaults to true.
+    }
+
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/FetchEmailError.kt

@@ -0,0 +1,7 @@
+package net.codinux.invoicing.email
+
+data class FetchEmailError(
+    val type: FetchEmailErrorType,
+    val messageId: Long?,
+    val error: Throwable
+)

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/FetchEmailErrorType.kt

@@ -0,0 +1,13 @@
+package net.codinux.invoicing.email
+
+enum class FetchEmailErrorType {
+    GetEmail,
+
+    GetMesssageBody,
+
+    GetAttachment,
+
+    ExtractInvoice,
+
+    ListenForNewEmails
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/FetchEmailsOptions.kt

@@ -0,0 +1,47 @@
+package net.codinux.invoicing.email
+
+import net.codinux.invoicing.email.model.Email
+import java.io.File
+import java.time.Instant
+import java.time.LocalDate
+import java.time.ZoneId
+
+open class FetchEmailsOptions(
+    /**
+     * The ID of the last retrieved message. If set, only messages newer than this ID will be fetched.
+     */
+    val lastRetrievedMessageId: Long? = null,
+
+    val downloadMessageBody: Boolean = true,
+    /**
+     * If set to true and message contains a plain text message body, then only the plain text message body is downloaded
+     * and the HTML message body ignored / not downloaded. Reduces process time about 50 % (if no attachments get downloaded).
+     */
+    val downloadOnlyPlainTextOrHtmlMessageBody: Boolean = true,
+    val downloadOnlyMessagesNewerThan: LocalDate? = null,
+
+    /**
+     * Set the extension (without the dot) of files that should be downloaded.
+     */
+    val downloadAttachmentsWithExtensions: List<String> = DefaultDownloadedAttachmentsWithExtensions,
+    val attachmentsDownloadDirectory: File = DefaultAttachmentsDownloadDirectory,
+
+    val emailFolderName: String = "INBOX",
+    val connectTimeoutSeconds: Int = 5,
+
+    val onError: ((FetchEmailError) -> Unit)? = null,
+    val onEmailReceived: ((Email) -> Unit)? = null
+) {
+    companion object {
+        val DefaultDownloadedAttachmentsWithExtensions = emptyList<String>()
+
+        val DefaultAttachmentsDownloadDirectory: File = File(System.getProperty("java.io.tmpdir"), "eInvoices").also { it.mkdirs() }
+    }
+
+
+    val minMessageDate: Instant? by lazy { downloadOnlyMessagesNewerThan?.atStartOfDay(ZoneId.systemDefault())?.toInstant() }
+
+    fun emailReceived(email: Email) {
+        onEmailReceived?.invoke(email)
+    }
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/FetchEmailsResult.kt

@@ -0,0 +1,9 @@
+package net.codinux.invoicing.email
+
+import net.codinux.invoicing.email.model.Email
+
+data class FetchEmailsResult(
+    val emails: List<Email>,
+    val overallError: Throwable?,
+    val messageSpecificErrors: List<FetchEmailError> = emptyList()
+)

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/FetchEmailsStatus.kt

@@ -0,0 +1,45 @@
+package net.codinux.invoicing.email
+
+import jakarta.mail.BodyPart
+import jakarta.mail.Message
+import jakarta.mail.Part
+import net.codinux.invoicing.email.model.EmailAccount
+import net.codinux.invoicing.filesystem.FileUtil
+import org.eclipse.angus.mail.imap.IMAPFolder
+import java.io.File
+
+data class FetchEmailsStatus(
+    val account: EmailAccount,
+    val folder: IMAPFolder,
+    val options: FetchEmailsOptions,
+    val messageSpecificErrors: MutableList<FetchEmailError> = mutableListOf()
+) {
+
+    val userAttachmentsDownloadDirectory: File by lazy {
+        val userDirName = FileUtil.removeIllegalFileCharacters(account.username)
+
+        File(options.attachmentsDownloadDirectory, userDirName).also { it.mkdirs() }
+    }
+
+
+    fun addError(type: FetchEmailErrorType, messageId: Long?, error: Throwable) =
+        addError(FetchEmailError(type, messageId, error))
+
+    fun addError(error: FetchEmailError) {
+        messageSpecificErrors.add(error)
+
+        options.onError?.invoke(error)
+    }
+
+    private fun getMessage(part: Part): Message? {
+        if (part is Message) {
+            return part
+        }
+
+        (part as? BodyPart)?.parent?.parent?.let { parent ->
+            return getMessage(parent)
+        }
+
+        return null
+    }
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/ListenForNewMailsOptions.kt

@@ -0,0 +1,26 @@
+package net.codinux.invoicing.email
+
+import net.codinux.invoicing.email.model.Email
+import java.io.File
+import java.util.concurrent.atomic.AtomicBoolean
+
+open class ListenForNewMailsOptions(
+    val stopListening: AtomicBoolean = AtomicBoolean(false),
+
+    downloadMessageBody: Boolean = true,
+    downloadOnlyPlainTextOrHtmlMessageBody: Boolean = true,
+
+    downloadAttachmentsWithExtensions: List<String> = DefaultDownloadedAttachmentsWithExtensions,
+    attachmentsDownloadDirectory: File = DefaultAttachmentsDownloadDirectory,
+
+    emailFolderName: String = "INBOX",
+    connectTimeoutSeconds: Int = 5,
+
+    onError: ((FetchEmailError) -> Unit)? = null,
+    onEmailReceived: (Email) -> Unit
+) : FetchEmailsOptions(
+    null,
+    downloadMessageBody, downloadOnlyPlainTextOrHtmlMessageBody, null,
+    downloadAttachmentsWithExtensions, attachmentsDownloadDirectory,
+    emailFolderName, connectTimeoutSeconds, onError, onEmailReceived
+)

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/model/ContentDisposition.kt

@@ -0,0 +1,11 @@
+package net.codinux.invoicing.email.model
+
+enum class ContentDisposition {
+    Body,
+
+    Inline,
+
+    Attachment,
+
+    Unknown
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/model/Email.kt

@@ -0,0 +1,45 @@
+package net.codinux.invoicing.email.model
+
+import java.time.Instant
+import java.time.ZoneId
+
+class Email(
+    /**
+     * Unique identifier of the message, used as identifier to retrieve further data of this message or as identifier
+     * of the last downloaded message (to continue fetching emails at messages newer than the message with this id).
+     *
+     * Actually the IMAP UID, but the user should not care which ID this value refers to.
+     * (messageUID: Unique identifier of a message in an email account. Survives e.g. expunging and moving the message to a different folder. This value.
+     * messageNumber: Non stable number. Message numbers e.g. change on expunge.
+     * messageId: Long string that is reference in inReplyTo field to identify to which message this message is a response of. Not of interest for us.
+     */
+    val messageId: Long,
+
+    val sender: EmailAddress?,
+    val subject: String,
+    val date: Instant,
+
+    val to: List<EmailAddress>,
+    val cc: List<EmailAddress> = emptyList(),
+    val bcc: List<EmailAddress> = emptyList(),
+    val replayTo: EmailAddress? = null,
+
+    val plainTextBody: String? = null,
+    val htmlBody: String? = null,
+
+    val contentLanguage: String? = null,
+    val isEncrypted: Boolean = false,
+
+    val attachments: List<EmailAttachment> = emptyList()
+) {
+    val plainTextOrHtmlBody: String? by lazy { plainTextBody ?: htmlBody }
+
+    val hasAttachments: Boolean by lazy { attachments.isNotEmpty() }
+
+    val hasEInvoiceAttachment: Boolean by lazy { attachments.any { it.containsEInvoice } }
+
+    val hasPdfAttachment: Boolean by lazy { attachments.any { it.isPdfFile } }
+
+
+    override fun toString() = "${date.atZone(ZoneId.systemDefault()).toLocalDate()} $sender: $subject, ${attachments.size} attachment(s)"
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/model/EmailAccount.kt

@@ -1,14 +1,14 @@
-package net.codinux.invoicing.mail
+package net.codinux.invoicing.email.model
 
-class MailAccount(
+class EmailAccount(
     val username: String,
     val password: String,
     /**
-     * For reading mails the IMAP server address, for sending mails the SMTP server address.
+     * For fetching emails the IMAP server address, for sending emails the SMTP server address.
      */
     val serverAddress: String,
     /**
-     * Even though not mandatory it's better to specify the port, otherwise default port is tried.
+     * Even though not mandatory it's better to specify the port, otherwise default port (993 for IMAP, 587 for SMTP) is used.
      */
     val port: Int? = null
 ) {

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/model/EmailAddress.kt

@@ -0,0 +1,16 @@
+package net.codinux.invoicing.email.model
+
+class EmailAddress(
+    /**
+     * The email address, like "a@b.com"
+     */
+    val address: String,
+    /**
+     * Sender or recipient's name like "Mahatma Gandhi"
+     */
+    val name: String? = null
+) {
+    override fun toString() =
+        if (name == null) address
+        else "$name <$address>"
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/email/model/EmailAttachment.kt

@@ -0,0 +1,26 @@
+package net.codinux.invoicing.email.model
+
+import net.codinux.invoicing.model.Invoice
+import java.io.File
+
+class EmailAttachment(
+    val filename: String,
+    val extension: String,
+    val size: Int?,
+    val disposition: ContentDisposition,
+    /**
+     * Attachment's media type like "application/xml", "application/pdf", ...
+     *
+     * Should always be non-null, but can theoretically be null.
+     */
+    val mediaType: String?,
+    val contentType: String?,
+    val invoice: Invoice? = null,
+    val file: File? = null
+) {
+    val containsEInvoice: Boolean by lazy { invoice != null }
+
+    val isPdfFile: Boolean by lazy { extension == "pdf" || mediaType == "application/pdf" }
+
+    override fun toString() = "$filename: $invoice"
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/filesystem/FileUtil.kt

@@ -0,0 +1,12 @@
+package net.codinux.invoicing.filesystem
+
+object FileUtil {
+
+    private val IllegalFileCharacters = listOf('\\', '/', ':', '*', '?', '"', '<', '>', '|', '\u0000')
+
+
+    fun removeIllegalFileCharacters(name: String, replacementChar: Char = '_') = name
+        .map { if (it in IllegalFileCharacters || it.code < 32) replacementChar else it }
+        .joinToString("")
+
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/filesystem/FilesystemInvoiceReader.kt

@@ -35,9 +35,13 @@ open class FilesystemInvoiceReader(
         val extension = file.extension.lowercase()
 
         if (extension == "pdf") {
-            eInvoiceReader.extractFromPdf(file.inputStream())
+            file.inputStream().use { inputStream ->
+                eInvoiceReader.extractFromPdf(inputStream)
+            }
         } else if (extension == "xml") {
-            eInvoiceReader.extractFromXml(file.inputStream())
+            file.inputStream().use { inputStream ->
+                eInvoiceReader.extractFromXml(inputStream)
+            }
         } else {
             null
         }

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/mail/MailAttachmentWithEInvoice.kt

@@ -1,18 +0,0 @@
-package net.codinux.invoicing.mail
-
-import net.codinux.invoicing.model.Invoice
-import java.io.File
-
-class MailAttachmentWithEInvoice(
-    val filename: String,
-    /**
-     * Attachment's media type like "application/xml", "application/pdf", ...
-     *
-     * Should always be non-null, but can theoretically be null.
-     */
-    val mediaType: String?,
-    val invoice: Invoice,
-    val file: File
-) {
-    override fun toString() = "$filename: $invoice"
-}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/mail/MailReader.kt

@@ -1,268 +0,0 @@
-package net.codinux.invoicing.mail
-
-import jakarta.mail.Folder
-import jakarta.mail.Message
-import jakarta.mail.Multipart
-import jakarta.mail.Part
-import jakarta.mail.Session
-import jakarta.mail.Store
-import jakarta.mail.event.MessageCountAdapter
-import jakarta.mail.event.MessageCountEvent
-import kotlinx.coroutines.*
-import net.codinux.invoicing.model.Invoice
-import net.codinux.invoicing.reader.EInvoiceReader
-import net.codinux.log.logger
-import org.eclipse.angus.mail.imap.IMAPFolder
-import java.io.File
-import java.time.Instant
-import java.util.*
-import java.util.concurrent.Executors
-import kotlin.math.max
-
-open class MailReader(
-    protected open val eInvoiceReader: EInvoiceReader = EInvoiceReader()
-) {
-
-    protected data class MessagePart(
-        val mediaType: String,
-        val part: Part
-    )
-
-
-    protected open val mailDispatcher = Executors.newFixedThreadPool(max(24, Runtime.getRuntime().availableProcessors() * 4)).asCoroutineDispatcher()
-
-    protected val log by logger()
-
-
-    open fun listenForNewReceivedEInvoices(account: MailAccount, downloadMessageBody: Boolean = false, emailFolderName: String = "INBOX", eInvoiceReceived: (MailWithInvoice) -> Unit) = runBlocking {
-        try {
-            connect(account) { store ->
-                val folder = store.getFolder(emailFolderName)
-                folder.open(Folder.READ_ONLY)
-
-                folder.addMessageCountListener(object : MessageCountAdapter() {
-                    override fun messagesAdded(event: MessageCountEvent) {
-                        event.messages.forEach { message ->
-                            findEInvoice(message, downloadMessageBody)?.let {
-                                eInvoiceReceived(it)
-                            }
-                        }
-                    }
-                })
-
-                launch(mailDispatcher) {
-                    keepConnectionOpen(account, folder)
-                }
-            }
-        } catch (e: Throwable) {
-            log.error(e) { "Listening to new received eInvoices of '${account.username}' failed" }
-        }
-
-        log.info { "Stopped listening to new received eInvoices of '${account.username}'" }
-    }
-
-    protected open suspend fun keepConnectionOpen(account: MailAccount, folder: Folder) {
-        log.info { "Listening to new mails of ${account.username}" }
-
-        // Use IMAP IDLE to keep the connection alive
-        while (true) {
-            if (!folder.isOpen) {
-                log.info { "Reopening inbox of ${account.username} ..." }
-                folder.open(Folder.READ_ONLY)
-            }
-
-            (folder as IMAPFolder).idle()
-
-            delay(250)
-        }
-    }
-
-
-    open fun listAllMessagesWithEInvoice(account: MailAccount, downloadMessageBody: Boolean = false, emailFolderName: String = "INBOX"): List<MailWithInvoice> {
-        try {
-            return connect(account) { store ->
-                val inbox = store.getFolder(emailFolderName)
-                inbox.open(Folder.READ_ONLY)
-
-                listAllMessagesWithEInvoiceInFolder(inbox, downloadMessageBody).also {
-                    inbox.close(false)
-                }
-            }
-        } catch (e: Throwable) {
-            log.error(e) { "Could not read mails of account $account" }
-        }
-
-        return emptyList()
-    }
-
-    protected open fun listAllMessagesWithEInvoiceInFolder(folder: Folder, downloadMessageBody: Boolean): List<MailWithInvoice> = runBlocking {
-        val messageCount = folder.messageCount
-        if (messageCount <= 0) {
-            return@runBlocking emptyList()
-        }
-
-        IntRange(1, messageCount).mapNotNull { messageNumber -> // message numbers start at 1
-            async(mailDispatcher) {
-                try {
-                    findEInvoice(folder.getMessage(messageNumber), downloadMessageBody)
-                } catch (e: Throwable) {
-                    log.error(e) { "Could not get message with messageNumber $messageNumber" }
-                    null
-                }
-            }
-        }
-            .awaitAll()
-            .filterNotNull()
-    }
-
-    protected open fun findEInvoice(message: Message, downloadMessageBody: Boolean): MailWithInvoice? {
-        try {
-            val parts = getAllMessageParts(message)
-
-            val attachmentsWithEInvoice = parts.mapNotNull { part ->
-                findEInvoice(part)
-            }
-
-            if (attachmentsWithEInvoice.isNotEmpty()) {
-                return MailWithInvoice(
-                    message.from?.joinToString(), message.subject ?: "",
-                    message.sentDate?.let { map(it) }, map(message.receivedDate), message.messageNumber,
-                    parts.any { it.mediaType == "application/pgp-encrypted" },
-                    if (downloadMessageBody) getPlainTextBody(parts) else null, if (downloadMessageBody) getHtmlBody(parts) else null,
-                    attachmentsWithEInvoice
-                )
-            }
-        } catch (e: Throwable) {
-            log.error(e) { "Could not read message $message" }
-        }
-
-        return null
-    }
-
-    protected open fun findEInvoice(messagePart: MessagePart): MailAttachmentWithEInvoice? {
-        try {
-            val part = messagePart.part
-            val invoice = tryToReadEInvoice(part, messagePart.mediaType)
-
-            if (invoice != null) {
-                val filename = File(part.fileName)
-                val file = File.createTempFile(filename.nameWithoutExtension, "." + filename.extension).also { file ->
-                    part.inputStream.use { it.copyTo(file.outputStream()) }
-                    file.deleteOnExit()
-                }
-
-                return MailAttachmentWithEInvoice(part.fileName, messagePart.mediaType, invoice, file)
-            }
-        } catch (e: Throwable) {
-            log.error(e) { "Could not check attachment '${messagePart.part.fileName}' (${messagePart.mediaType}) for eInvoice" }
-        }
-
-        return null
-    }
-
-    protected open fun tryToReadEInvoice(part: Part, mediaType: String?): Invoice? = try {
-        val filename = part.fileName?.lowercase() ?: ""
-
-        if (filename.endsWith(".pdf") || mediaType == "application/pdf" || mediaType == "application/octet-stream") {
-            eInvoiceReader.extractFromPdf(part.inputStream)
-        } else if (filename.endsWith(".xml") || mediaType == "application/xml" || mediaType == "text/xml") {
-            eInvoiceReader.extractFromXml(part.inputStream)
-        } else {
-            null
-        }
-    } catch (e: Throwable) {
-        log.debug(e) { "Could not extract invoices from ${part.fileName}" }
-        null
-    }
-
-
-    protected open fun getAllMessageParts(part: Part): List<MessagePart> {
-        return if (part.isMimeType("multipart/*")) {
-            val multipart = part.content as Multipart
-            val parts = IntRange(0, multipart.count - 1).map { multipart.getBodyPart(it) }
-
-            parts.flatMap { subPart ->
-                getAllMessageParts(subPart)
-            }
-        } else {
-            val mediaType = getMediaType(part)
-            if (mediaType == null) {
-                log.warn { "Could not determine media type of message part $part" }
-                emptyList()
-            } else {
-                listOf(MessagePart(mediaType, part))
-            }
-        }
-    }
-
-    /**
-     * In most cases parameters are added to content-type's media type, e.g.
-     * - text/html; charset=utf-8
-     * - multipart/related; boundary="boundary-related"; type="text/html"
-     *
-     * -> This method removes parameters and return media type (first part) only
-     */
-    protected open fun getMediaType(part: Part): String? = part.contentType?.lowercase()?.let { contentType ->
-        val indexOfSeparator = contentType.indexOf(';')
-
-        if (indexOfSeparator > -1) {
-            contentType.substring(0, indexOfSeparator)
-        } else {
-            contentType
-        }
-    }
-
-    protected open fun getPlainTextBody(parts: Collection<MessagePart>) = getBodyWithMediaType(parts, "text/plain")
-
-    protected open fun getHtmlBody(parts: Collection<MessagePart>) = getBodyWithMediaType(parts, "text/html")
-
-    protected open fun getBodyWithMediaType(parts: Collection<MessagePart>, mediaType: String): String? = try {
-        val partsForMediaType = parts.filter { it.mediaType == mediaType }
-
-        if (partsForMediaType.size == 1) {
-            partsForMediaType.first().part.content as? String
-        } else if (partsForMediaType.isEmpty()) {
-            null
-        } else {
-            val partsForMediaTypeWithoutFilename = partsForMediaType.filter { it.part.fileName == null }
-            if (partsForMediaTypeWithoutFilename.size == 1) {
-                partsForMediaTypeWithoutFilename.first().part.content as? String
-            } else if (partsForMediaTypeWithoutFilename.isEmpty()) {
-                log.warn { "Multiple message parts with media type '$mediaType' found, but all have a filename" }
-                null
-            } else { // if there are multiple parts without filename, then the second one is in most cases quoted previous message(s)
-                partsForMediaTypeWithoutFilename.mapNotNull { it.part.content as? String }.joinToString("\r\n")
-            }
-        }
-    } catch (e: Throwable) {
-        log.error(e) { "Could not get message body for media type '$mediaType'" }
-        null
-    }
-
-    protected open fun map(date: Date): Instant =
-        date.toInstant()
-
-
-    protected open fun <T> connect(account: MailAccount, connected: (Store) -> T): T {
-        val properties = mapAccountToJavaMailProperties(account)
-
-        val session = Session.getInstance(properties)
-        session.getStore("imap").use { store ->
-            store.connect(account.serverAddress, account.username, account.password)
-
-            return connected(store)
-        }
-    }
-
-    protected open fun mapAccountToJavaMailProperties(account: MailAccount) = Properties().apply {
-        put("mail.store.protocol", "imap")
-
-        put("mail.imap.host", account.serverAddress)
-        put("mail.imap.port", account.port?.toString() ?: "993")  // Default IMAP over SSL
-        put("mail.imap.ssl.enable", "true")
-
-        put("mail.imap.connectiontimeout", "5000")
-        put("mail.imap.timeout", "5000")
-    }
-
-}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/mail/MailWithInvoice.kt

@@ -1,27 +0,0 @@
-package net.codinux.invoicing.mail
-
-import java.time.Instant
-import java.time.ZoneId
-
-class MailWithInvoice(
-    val sender: String?,
-    val subject: String,
-    val sent: Instant?,
-    val received: Instant,
-    /**
-     * From documentation of underlying mail library:
-     * "Since message numbers can change within a session if the folder is expunged, clients are advised not to use
-     * message numbers as references to messages."
-     *
-     * -> use with care. Message numbers are not valid / the same anymore after expunge.
-     */
-    val messageNumber: Int,
-    val isEncrypted: Boolean = false,
-    val plainTextBody: String?,
-    val htmlBody: String?,
-    val attachmentsWithEInvoice: List<MailAttachmentWithEInvoice>
-) {
-    val plainTextOrHtmlBody: String? by lazy { plainTextBody ?: htmlBody }
-
-    override fun toString() = "${(sent ?: received).atZone(ZoneId.systemDefault()).toLocalDate()} $sender: $subject, ${attachmentsWithEInvoice.size} invoice(s)"
-}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/model/EInvoiceXmlFormat.kt

@@ -0,0 +1,10 @@
+package net.codinux.invoicing.model
+
+enum class EInvoiceXmlFormat {
+    /**
+     * Factur-X is equal / synonym to ZUGFeRD 2
+     */
+    FacturX,
+
+    XRechnung
+}

e-invoice-domain/src/main/kotlin/net/codinux/invoicing/reader/EInvoiceReader.kt

@@ -2,6 +2,7 @@ package net.codinux.invoicing.reader
 
 import net.codinux.invoicing.mapper.MustangMapper
 import net.codinux.invoicing.model.Invoice
+import net.codinux.log.logger
 import org.mustangproject.ZUGFeRD.ZUGFeRDInvoiceImporter
 import java.io.File
 import java.io.InputStream
@@ -16,11 +17,19 @@ open class EInvoiceReader(
         )
     }
 
+    private val log by logger()
 
-    open fun extractFromXml(xmlFile: File) = extractFromXml(xmlFile.inputStream())
+
+    open fun extractFromXmlOrNull(xmlFile: File) = orNull { extractFromXml(xmlFile) }
+
+    open fun extractFromXml(xmlFile: File) = xmlFile.inputStream().use { extractFromXml(it) }
+
+    open fun extractFromXmlOrNull(stream: InputStream) = orNull { extractFromXml(stream) }
 
     open fun extractFromXml(stream: InputStream) = extractFromXml(stream.reader().readText())
 
+    open fun extractFromXmlOrNull(xml: String) = orNull { extractFromXml(xml) }
+
     open fun extractFromXml(xml: String): Invoice {
         val importer = ZUGFeRDInvoiceImporter() // XRechnungImporter only reads properties but not to a Invoice object
         importer.fromXML(xml)
@@ -28,7 +37,12 @@ open class EInvoiceReader(
         return extractInvoice(importer)
     }
 
-    open fun extractFromPdf(pdfFile: File) = extractFromPdf(pdfFile.inputStream())
+
+    open fun extractFromPdfOrNull(pdfFile: File) = orNull { extractFromPdf(pdfFile) }
+
+    open fun extractFromPdf(pdfFile: File) = pdfFile.inputStream().use { extractFromPdf(it) }
+
+    open fun extractFromPdfOrNull(stream: InputStream) = orNull { extractFromPdf(stream) }
 
     open fun extractFromPdf(stream: InputStream): Invoice {
         val importer = ZUGFeRDInvoiceImporter(stream)
@@ -36,7 +50,12 @@ open class EInvoiceReader(
         return extractInvoice(importer)
     }
 
-    open fun extractXmlFromPdf(pdfFile: File) = extractXmlFromPdf(pdfFile.inputStream())
+
+    open fun extractXmlFromPdfOrNull(pdfFile: File) = orNull { extractXmlFromPdf(pdfFile) }
+
+    open fun extractXmlFromPdf(pdfFile: File) = pdfFile.inputStream().use { extractXmlFromPdf(it) }
+
+    open fun extractXmlFromPdfOrNull(stream: InputStream) = orNull { extractXmlFromPdf(stream) }
 
     open fun extractXmlFromPdf(stream: InputStream): String {
         val importer = ZUGFeRDInvoiceImporter(stream)
@@ -58,4 +77,13 @@ open class EInvoiceReader(
         return mapper.mapToInvoice(invoice)
     }
 
+
+    protected open fun <T> orNull(action: () -> T): T? =
+        try {
+            action()
+        } catch (e: Throwable) {
+            log.debug(e) { "Action caused an exception, but orNull() was called" }
+            null
+        }
+
 }

e-invoice-domain/src/test/kotlin/net/codinux/invoicing/Demonstration.kt

@@ -1,8 +1,9 @@
 package net.codinux.invoicing
 
 import net.codinux.invoicing.creation.EInvoiceCreator
-import net.codinux.invoicing.mail.MailAccount
-import net.codinux.invoicing.mail.MailReader
+import net.codinux.invoicing.email.model.EmailAccount
+import net.codinux.invoicing.email.EmailsFetcher
+import net.codinux.invoicing.model.EInvoiceXmlFormat
 import net.codinux.invoicing.model.Invoice
 import net.codinux.invoicing.model.InvoiceItem
 import net.codinux.invoicing.model.Party
@@ -24,15 +25,19 @@ class Demonstration {
         val invoiceFromXml = reader.extractFromXml(File("XRechnung.xml"))
     }
 
-    fun fromMail() {
-        val mailReader = MailReader()
+    fun fromEmail() {
+        val emailsFetcher = EmailsFetcher()
 
-        val mailsWithEInvoices = mailReader.listAllMessagesWithEInvoice(MailAccount(
-            username = "", // your mail account username
-            password = "", // your mail account username
+        val fetchResult = emailsFetcher.fetchAllEmails(EmailAccount(
+            username = "", // your email account username
+            password = "", // your email account username
             serverAddress = "", // IMAP server address
-            port = null // IMAP server port, leave null if default port 993
+            port = null // IMAP server port, can be left null for default port 993
         ))
+
+        fetchResult.emails.forEach { email ->
+            println("${email.sender}: ${email.attachments.firstNotNullOfOrNull { it.invoice }?.totalAmounts?.duePayableAmount}")
+        }
     }
 
     fun validate() {
@@ -53,7 +58,7 @@ class Demonstration {
         val creator = EInvoiceCreator()
 
         // create a PDF that also contains the eInvoice as XML attachment
-        creator.createFacturXPdf(invoice, pdfResultFile)
+        creator.createPdfWithAttachedXml(invoice, pdfResultFile)
 
         // create only the XML file
         val xml = creator.createFacturXXml(invoice)
@@ -72,9 +77,9 @@ class Demonstration {
         creator.attachInvoiceXmlToPdf(invoice, existingPdf, output)
 
         // or if you already have the invoice XML:
-        val invoiceXml: String = "..." // e.g. creator.createZugferdXml(invoice)
+        val invoiceXml = creator.createXRechnungXml(invoice) // or creator.createZugferdXml(invoice), ...
 
-        creator.attachInvoiceXmlToPdf(invoiceXml, existingPdf, output)
+        creator.attachInvoiceXmlToPdf(invoiceXml, EInvoiceXmlFormat.XRechnung, existingPdf, output)
     }
 
 

e-invoice-domain/src/test/kotlin/net/codinux/invoicing/creation/EInvoiceCreatorTest.kt

@@ -1,5 +1,6 @@
 package net.codinux.invoicing.creation
 
+import net.codinux.invoicing.model.EInvoiceXmlFormat
 import net.codinux.invoicing.test.DataGenerator
 import net.codinux.invoicing.test.InvoiceAsserter
 import org.mustangproject.ZUGFeRD.ZUGFeRDInvoiceImporter
@@ -30,13 +31,26 @@ class EInvoiceCreatorTest {
     }
 
     @Test
-    fun createFacturXPdf() {
+    fun createPdfWithAttachedXml_FacturX() {
         val invoice = createInvoice()
         val testFile = File.createTempFile("Zugferd", ".pdf")
 
-        underTest.createFacturXPdf(invoice, testFile)
+        underTest.createPdfWithAttachedXml(invoice, testFile, EInvoiceXmlFormat.FacturX)
 
-        val importer = ZUGFeRDInvoiceImporter(testFile.inputStream())
+        val importer = testFile.inputStream().use { ZUGFeRDInvoiceImporter(it) }
+        val xml = String(importer.rawXML, Charsets.UTF_8)
+
+        assertInvoiceXml(xml)
+    }
+
+    @Test
+    fun createPdfWithAttachedXml_XRechnung() {
+        val invoice = createInvoice()
+        val testFile = File.createTempFile("Zugferd", ".pdf")
+
+        underTest.createPdfWithAttachedXml(invoice, testFile, EInvoiceXmlFormat.XRechnung)
+
+        val importer = testFile.inputStream().use { ZUGFeRDInvoiceImporter(it) }
         val xml = String(importer.rawXML, Charsets.UTF_8)
 
         assertInvoiceXml(xml)

e-invoice-domain/src/test/kotlin/net/codinux/invoicing/email/EmailsFetcherTest.kt

@@ -0,0 +1,39 @@
+package net.codinux.invoicing.email
+
+import assertk.assertThat
+import assertk.assertions.isEmpty
+import assertk.assertions.isNotEmpty
+import assertk.assertions.isNull
+import net.codinux.invoicing.email.model.EmailAccount
+import org.junit.jupiter.api.Test
+import kotlin.test.Ignore
+
+@Ignore // not an automatic test, set your email account settings below
+class EmailsFetcherTest {
+
+    companion object {
+        // specify your email account here
+        private val emailAccount = EmailAccount(
+            username = "",
+            password = "",
+            serverAddress = "",
+            port = null // IMAP server port, can be left null for default port 993
+        )
+    }
+
+
+    private val underTest = EmailsFetcher()
+
+
+    @Test
+    fun fetchAllEmails() {
+        val result = underTest.fetchAllEmails(emailAccount, FetchEmailsOptions(downloadMessageBody = true))
+
+        assertThat(result.overallError).isNull()
+        assertThat(result.emails).isNotEmpty()
+
+        val emailsWithoutBody = result.emails.filter { it.plainTextOrHtmlBody == null && it.isEncrypted == false }
+        assertThat(emailsWithoutBody).isEmpty()
+    }
+
+}

e-invoice-domain/src/test/kotlin/net/codinux/invoicing/mail/MailReaderTest.kt

@@ -1,36 +0,0 @@
-package net.codinux.invoicing.mail
-
-import assertk.assertThat
-import assertk.assertions.isEmpty
-import assertk.assertions.isNotEmpty
-import org.junit.jupiter.api.Test
-import kotlin.test.Ignore
-
-@Ignore // not an automatic test, set your mail account settings below
-class MailReaderTest {
-
-    companion object {
-        // specify your mail account here
-        private val mailAccount = MailAccount(
-            username = "",
-            password = "",
-            serverAddress = "",
-            port = null // can be left as null if default port 993 is used
-        )
-    }
-
-
-    private val underTest = MailReader()
-
-
-    @Test
-    fun listAllMessagesWithEInvoice() {
-        val result = underTest.listAllMessagesWithEInvoice(mailAccount, true)
-
-        assertThat(result).isNotEmpty()
-
-        val messagesWithoutBody = result.filter { it.plainTextOrHtmlBody == null }
-        assertThat(messagesWithoutBody).isEmpty()
-    }
-
-}

e-invoice-domain/src/test/resources/logback-test.xml

@@ -21,4 +21,12 @@
         <appender-ref ref="STDOUT"/>
     </root>
 
+    <!-- Apache FOP will flood otherwise the log so that test run crashes -->
+    <logger name="org.apache.fop" level="INFO">
+        <appender-ref ref="STDOUT"/>
+    </logger>
+    <logger name="org.apache.xmlgraphics.image.loader.spi.ImageImplRegistry" level="INFO">
+        <appender-ref ref="STDOUT"/>
+    </logger>
+
 </configuration>

gradle.properties

@@ -1,5 +1,7 @@
 kotlin.code.style=official
 
+org.gradle.jvmargs=-Xmx4G
+
 org.gradle.parallel=true