带有包含图像的 HTML 正文的日历邀请答案

【问题标题】：Calendar Invite with HTML body that contains images带有包含图像的 HTML 正文的日历邀请
【发布时间】：2017-02-19 04:19:32
【问题描述】：

我无法将我的图像显示为邮件的 HTML 正文的一部分，该邮件还包含日历附件 (iCal)。

我正在尝试做的是：发送 Outlook 可识别且还包含 HTML 正文（也显示在 Outlook 2013 中）的日历邀请。该 HTML 应内联显示页眉和页脚图像。

我的代码在 gmail 中查看时有效，但它不会在 Outlook 中显示图像 - 而是在我希望实际显示图像的正文位置显示“header.jpg”和“footer.jpg”。

我已尝试对此代码库进行大量修改 - 要么忽略日历邀请部分（然后图像工作），要么日历邀请部分工作并且图像不显示但被“header. jpg”和“screen.jpg”文件，双击时打开正常。我可以解决这个问题并在 Outlook 中内联显示图像吗？

这是我正在使用的代码（剪掉不相关的东西）：

var header = new LinkedResource("header.jpg", MediaTypeNames.Image.Jpeg);
header.ContentId = Guid.NewGuid().ToString();
header.TransferEncoding = TransferEncoding.Base64;
header.ContentType = new ContentType("image/jpg");
header.ContentType.Name = "header.jpg";
header.ContentLink = new Uri(string.Format("cid:{0}", header.ContentId));

var screen = new LinkedResource("screen.jpg", MediaTypeNames.Image.Jpeg);
screen.ContentId = Guid.NewGuid().ToString();
screen.TransferEncoding = TransferEncoding.Base64;
screen.ContentType = new ContentType("image/jpg");
screen.ContentType.Name = "screen.jpg";
screen.ContentLink = new Uri(string.Format("cid:{0}", screen.ContentId));


var sb = new System.Text.StringBuilder();

var dtStart = appointmentStart;
var dtEnd = appointmentEnd;

var htmlcontent = string.Format("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\">" +
    "<HTML><HEAD><META http-equiv=Content-Type content=\"multipart/alternative; charset=iso-8859-1\"></HEAD>" +
    "<BODY>" +
    "<img src=\"cid:" + header.ContentId + "\"/>" +
    "<div><strong>The bold works fine, but the header and footer don't work! /strong></div>" +
   "<br />" +
   "<div><img src=\"cid:" + screen.ContentId + "\"/></div>" +
   "</BODY></HTML>"
   );

var plaincontent = String.Format("snip snip");

var av1 = AlternateView.CreateAlternateViewFromString(htmlcontent, new ContentType("text/html"););
av1.LinkedResources.Add(header);
av1.LinkedResources.Add(screen);

sb.AppendLine("BEGIN:VCALENDAR");
sb.AppendLine("VERSION:2.0");
sb.AppendLine("METHOD:REQUEST");
sb.AppendLine("BEGIN:VEVENT");
sb.AppendLine(request.ContactEmail);
sb.AppendLine("CLASS:PUBLIC");
sb.AppendLine(string.Format("CREATED:{0:yyyyMMddTHHmmss}", DateTime.Now));
sb.AppendLine("DESCRIPTION:" + plaincontent);
sb.AppendLine("X-ALT-DESC;FMTTYPE=text/html:" + htmlcontent);
sb.AppendLine(string.Format("DTSTART:{0:yyyyMMddTHHmmssZ}", dtStart.ToUniversalTime()));
sb.AppendLine(string.Format("DTEND:{0:yyyyMMddTHHmmssZ}", dtEnd.ToUniversalTime()));
sb.AppendLine(string.Format("DTSTAMP:{0:yyyyMMddTHHmmssZ}", DateTime.Now.ToUniversalTime()));
sb.AppendLine("ORGANIZER;CN=\"TheOrganizer\":mailto:" + "TheOrganizer@foobar.com");
sb.AppendLine("SEQUENCE:0");
sb.AppendLine("UID:" + request.EmailNotificationUniqueId);
sb.AppendLine("LOCATION:" + request.Location + " : " + request.LocationInformation);
sb.AppendLine("SUMMARY;LANGUAGE=en-us:" + "removed");
sb.AppendLine("BEGIN:VALARM");
sb.AppendLine("TRIGGER:-PT1440M");
sb.AppendLine("ACTION:DISPLAY");
sb.AppendLine("DESCRIPTION:Reminder");
sb.AppendLine("END:VALARM");
sb.AppendLine("END:VEVENT");
sb.AppendLine("END:VCALENDAR");

var icsView = AlternateView.CreateAlternateViewFromString(sb.ToString(), new ContentType("text/calendar"));

var message = new MailMessage();

message.AlternateViews.Add(body);
message.AlternateViews.Add(icsView);

return message;

有什么根本上的错误吗？这似乎应该非常简单明了。我已经用普通的电子邮件做了很多次了，但似乎 Outlook 不喜欢 HTML 替代视图正文中带有图像的 .ics 附件。 HTML 正文工作正常（显示为粗体），但嵌入的图像无法显示。

我尝试过使用 base64 手动编码图像，但这根本没有帮助。我尝试过在 htmlContent var 中使用和不使用 HTML 标头标签，这也没有任何区别。

这不应该这么难 - 我错过了什么？

编辑：这是谷歌的消息来源。这在谷歌浏览器窗口中工作正常（显示正确。）不幸的是，在 Outlook 中，消息不起作用......也许交换服务器正在抑制内部消息的图像？那是一回事吗？

Delivered-To: snip@gmail.com
Received: by 10.182.167.74 with SMTP id zm10csp2847908obb;
        Fri, 7 Oct 2016 15:42:14 -0700 (PDT)
X-Received: by 10.37.171.105 with SMTP id u96mr17483671ybi.63.1475880134797;
        Fri, 07 Oct 2016 15:42:14 -0700 (PDT)
Return-Path: <snip@snip.com>
Received: from msg12.snip.com (msg12.snip.com. [192.195.66.28])
        by mx.google.com with ESMTPS id q11si2985157ywc.340.2016.10.07.15.42.14
        for <snip@gmail.com>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Fri, 07 Oct 2016 15:42:14 -0700 (PDT)
Received-SPF: pass (google.com: domain of snip@snip.com designates 192.195.66.28 as permitted sender) client-ip=192.195.66.28;
Authentication-Results: mx.google.com;
       spf=pass (google.com: domain of snip@snip.com designates 192.195.66.28 as permitted sender) smtp.mailfrom=snip@snip.com
Received: from int11.snip.pvt (int11.snip.pvt [153.6.62.222]) by msg12.snip.com (Sentrion-MTA-4.3.1/Sentrion-MTA-4.2.2) with ESMTP id u97MgC5a022486 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for <snip@gmail.com>; Fri, 7 Oct 2016 22:42:12 GMT
Received: from snip.com (snip.com [snip]) by int11.snip.pvt (Sentrion-MTA-4.3.1/Sentrion-MTA-4.2.2) with ESMTP id u97MgBAv016400 for <snip@gmail.com>; Fri, 7 Oct 2016 22:42:12 GMT
Received: from snip.com with Microsoft SMTPSVC(7.5.7601.17514);
     Fri, 7 Oct 2016 18:42:12 -0400
MIME-Version: 1.0
From: snip <snip@snip.com>
To: snip@gmail.com
Date: 7 Oct 2016 18:42:12 -0400
Content-Type: multipart/alternative; boundary=--boundary_0_8278962b-71cf-4ca1-9a64-5fb9629f2042
Message-ID: <5U9T3T00000050@snip.com>
X-OriginalArrivalTime: 07 Oct 2016 22:42:12.0895 (UTC) FILETIME=[0BC44AF0:01D220EC]
X-Flow-Control: Sendmail Flow Controller v2.2.5 int11.snip.pvt u97MgBAv016400
X-Flow-Control-Info: class=Default rcpts=1 size=37636

----boundary_0_8278962b-71cf-4ca1-9a64-5fb9629f2042
Content-Type: multipart/related; boundary=--boundary_1_306bb8e7-fb92-4eab-bf5c-b7393cf499ac; type="text/html"

----boundary_1_306bb8e7-fb92-4eab-bf5c-b7393cf499ac
Content-Type: text/html
Content-Transfer-Encoding: quoted-printable

<img src=3D"cid:443ba735-6376-45a1-a5af-6c679321baa2"/><div><strong>The bol=
d works fine, but the header and footer don't work!</strong></div><br /><di=
v><img src=3D"cid:145c43b0-da9e-40c4-b149-3a149fbc4503"/></div>
----boundary_1_306bb8e7-fb92-4eab-bf5c-b7393cf499ac
Content-Type: image/jpeg
Content-Transfer-Encoding: base64
Content-ID: <443ba735-6376-45a1-a5af-6c679321baa2>


----boundary_1_306bb8e7-fb92-4eab-bf5c-b7393cf499ac
Content-Type: image/jpeg
Content-Transfer-Encoding: base64
Content-ID: <145c43b0-da9e-40c4-b149-3a149fbc4503>


----boundary_1_306bb8e7-fb92-4eab-bf5c-b7393cf499ac--
----boundary_0_8278962b-71cf-4ca1-9a64-5fb9629f2042
Content-Type: text/calendar
Content-Transfer-Encoding: base64
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----boundary_0_8278962b-71cf-4ca1-9a64-5fb9629f2042--

【问题讨论】：

您是否检查过 Outlook 中的设置以确定是否有问题引起？ slipstick.com/problems/…
我会检查的 - 但图像显示正常邮件消息正常。唯一的问题是当我尝试在包含 iCal 替代视图的消息中显示它们时。删除它并且图像显示得很好（但当然我没有收到我需要的日历邀请。）
我尝试了该链接中的所有建议 - 它们都不适用于我当前的环境。所有设置都已取消勾选。
你能发布邮件的完整 MIME 源吗？
不确定如何在不破解注册表的情况下将其拖出 Outlook（我可能会也可能不会这样做。）当我将消息发送到 gmail 时，它可以正常工作 - 所以不确定是否可能当消息仅在内部路由时，内部交换服务器正在做某事？无论如何，将其添加到原始帖子中。让我知道这是否是您需要的...

标签： c# outlook icalendar mailmessage

【解决方案1】：

尝试使用下面的代码，其中包含一种附加内联图像以及电子邮件邀请和普通附件的方法，只需根据您的需要调整代码

private String senderAddress = "YOUR EMAIL ADDRESS";
    private final String password = "YOUR EMAIL PASSWORD";
    public static SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd'T'HHmm'00'");
    public static SimpleDateFormat dateParser = new SimpleDateFormat("dd-MM-yyyy HH:mm");
    public static SimpleDateFormat dateFormater = new SimpleDateFormat("dd-MM-yyyy");

    public String getSenderAddress() {
        return senderAddress;
    }

    public String getPassword() {
        return password;
    }

    public Session getMailSession() {

        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", "587");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");

        return Session.getInstance(props, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(getSenderAddress(), getPassword());
            }
        });
    }

    public String newSend(Invitation invitation, String methodType)  {

        String UID = null;

        // register the text/calendar mime type
        MimetypesFileTypeMap mimetypes = (MimetypesFileTypeMap) MimetypesFileTypeMap.getDefaultFileTypeMap();
        mimetypes.addMimeTypes("text/calendar ics ICS");

        // register the handling of text/calendar mime type
        MailcapCommandMap mailcap = (MailcapCommandMap) MailcapCommandMap.getDefaultCommandMap();
        mailcap.addMailcap("text/calendar;; x-java-content-handler=com.sun.mail.handlers.text_plain");

        MimeMessage message = new MimeMessage(getMailSession());
        try {
            message.setFrom(new InternetAddress(senderAddress));
            message.setSubject(invitation.getSubject());
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(invitation.getTo()));

            Multipart multipart = new MimeMultipart("mixed");
            invitation.setDescription(getHtmlWithEncodedImages(multipart,invitation));

            Multipart mpMixedAlternative = newChild(multipart, "alternative");

            // html part
            BodyPart messageBodyPart = buildHtmlTextPart(invitation);
            mpMixedAlternative.addBodyPart(messageBodyPart);

            // Add part two, the calendar
            BodyPart calendarPart = buildCalendarPart(invitation, methodType);
            calendarPart.setDisposition(BodyPart.INLINE);
            mpMixedAlternative.addBodyPart(calendarPart);

            addAttachment(multipart);
            // Put the multipart in message
            message.setContent(multipart);

            // send the message
            Transport transport = getMailSession().getTransport("smtp");
            transport.connect();


            transport.sendMessage(message, message.getAllRecipients());

            transport.close();
            UID = invitation.getTo() + "" + invitation.getStartdate().toString() + "" + invitation.getStarttime();
        } catch (Exception e) {
            //TODO logger log exception
        }
        return UID;
    }

    private void addAttachment(Multipart multipart) {

        MimeBodyPart mbpAttachment = new MimeBodyPart();

        File file=new File("C:/users/ishan.juneja/Desktop/temp.txt");
        DataSource datasource=new FileDataSource(file);
        try {
            mbpAttachment.setDataHandler(new DataHandler(datasource));
            mbpAttachment.setDisposition(BodyPart.ATTACHMENT);

            mbpAttachment.setFileName("temp.txt");
            multipart.addBodyPart(mbpAttachment);
        } catch (MessagingException e) {
            // TODO logger log exception
        }


    }

    public String uploadImage(MultipartFile file){

        byte[] bytes;
        try {
            String path = System.getProperty("catalina.home");
            File dir = new File(path+"/tmpFiles");
            if(!dir.isDirectory()){
                dir.mkdir();
                }
            bytes = file.getBytes();
            File serverfile = new File(dir.getAbsolutePath()+"/"+file.getName()+Math.random()+".png");
            BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(serverfile));
            stream.write(bytes);
            stream.close();

            System.out.println("file uploaded "+serverfile.getAbsolutePath());

            String hostname="Unknown";
            try {
                hostname = InetAddress.getLocalHost().getHostName();
            } catch (UnknownHostException e1) {
                e1.printStackTrace();
            }


            return "{\"location\" : \"http://"+hostname+":8080/emailinvitation/image/path/"+serverfile.getName()+"\"}";

        } catch (IOException e) {
        }

        return "{\"location\":\"http://localhost:8080/emailinvitation/image/path/unknown.png\"}";
    }

    private Multipart newChild(Multipart parent, String alternative) {
        MimeMultipart child = new MimeMultipart(alternative);
        MimeBodyPart mbp = new MimeBodyPart();
        try {
            parent.addBodyPart(mbp);
            mbp.setContent(child);
        } catch (MessagingException e) {
            // TODO logger log exception
        }

        return child;
    }

    private BodyPart buildCalendarPart(Invitation invitation, String methodType) throws Exception {

        Date date1 = dateParser.parse(dateFormater.format(invitation.getStartdate()) + " " + invitation.getStarttime());
        String startDate = timeZoneToUTC(invitation, date1);

        Date date2 = dateParser.parse(dateFormater.format(invitation.getEnddate()) + " " + invitation.getEndtime());
        String endDate = timeZoneToUTC(invitation, date2);

        BodyPart calendarPart = new MimeBodyPart();


        String calendarContent = "BEGIN:VCALENDAR\n" + "METHOD:" + methodType + "\n" + "PRODID: BCP - Meeting\n"
                + "VERSION:2.0\n" + "X-WR-TIMEZONE:" + invitation.getTimezone() + "\n" + "BEGIN:VEVENT\n" + "DTSTAMP:"
                + startDate + "Z\n" + "DTSTART:" + startDate + "Z\n" + "DTEND:" + endDate + "Z\n"
                + "SUMMARY:test request\n" + "UID:" + invitation.getTo() + "" + startDate + "\n"
                + "ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=FALSE:MAILTO:" + invitation.getTo() + "\n"
                + "ORGANIZER:MAILTO:" + senderAddress + "\n" + "LOCATION:Test\n"  + "SEQUENCE:0\n"
                + "PRIORITY:5\n" + "CLASS:PUBLIC\n" + "STATUS:CONFIRMED\n" + "TRANSP:OPAQUE\n" + "BEGIN:VALARM\n"
                + "ACTION:DISPLAY\n" + "DESCRIPTION:REMINDER\n" + "TRIGGER;RELATED=START:-PT00H15M00S\n"
                + "END:VALARM\n" + "END:VEVENT\n" + "END:VCALENDAR";

        calendarPart.addHeader("Content-Class", "urn:content-classes:calendarmessage");
        calendarPart.setContent(calendarContent, "text/calendar;method=" + methodType);

        return calendarPart;
    }

    private BodyPart buildHtmlTextPart(Invitation invitation) {

        MimeBodyPart descriptionPart = new MimeBodyPart();
        String content = invitation.getDescription();
        try {
            descriptionPart.setContent(content, "text/html; charset=utf-8");
        } catch (MessagingException e) {
            // TODO logger log exception

        }
        return descriptionPart;
    }

    private void addImages(Multipart parent,String filename)  {

        MimeBodyPart mbpAttachment = new MimeBodyPart();

        try {

            File file = new File("C:\\apache-tomcat-8.5.24\\tmpFiles\\"+filename);
            FileDataSource ds = new FileDataSource(file);
            mbpAttachment.setDataHandler(new DataHandler(ds));
            mbpAttachment.setDisposition(BodyPart.INLINE);
            mbpAttachment.setHeader("Content-ID", filename);
            mbpAttachment.setFileName(filename);
            parent.addBodyPart(mbpAttachment);
        } catch (Exception e) {
            //TODO logger log exception

        }


    }

    private String timeZoneToUTC(Invitation invitation, Date date) {
        ZoneId zone = ZoneId.of(invitation.getTimezone());

        String date1 = dateParser.format(date);

        DateTimeFormatter fmt = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm").withZone(zone);

        ZonedDateTime utc = ZonedDateTime.parse(date1, fmt).withZoneSameInstant(ZoneId.of("UTC"));

        Timestamp sqlTs = Timestamp.valueOf(utc.toLocalDateTime());

        return dateFormat.format(sqlTs);
    }

    public String getHtmlWithEncodedImages(Multipart parent,Invitation invitation) {

        String temp = invitation.getDescription();
        String html="<html><body>"+invitation.getDescription()+"</body></html>";
        Document document = Jsoup.parse(html);
        Elements allElements=document.body().getElementsByTag("img");
        for (Element element : allElements) {
            String elementstring=element.toString();
            String tempfilename = elementstring.substring(elementstring.indexOf("file"));
            String filename=tempfilename.substring(0,tempfilename.indexOf('"'));
            temp=temp.replace(elementstring.substring(elementstring.indexOf('"'), elementstring.lastIndexOf('"')),"\"cid:"+filename);

            addImages(parent, filename);
        }
        System.out.println("--++--"+temp);
        return temp;
    }

【讨论】：