Gmail 问题 - 使用 MailKit 嵌入图像

Question

我正在尝试使用 MailKit 发送带有嵌入图像的电子邮件。它适用于 MS Outlook。但是，图像不会在 Gmail 中显示为嵌入图像。我尝试以 "data:image/png;base64," 格式附加到它也适用于 Outlook，但不适用于 Gmail。

如有任何帮助，我们将不胜感激！

public string SendEmail (MyModel myModel)
{
    var message = new MimeMessage();
    var bodyBuilder = new BodyBuilder
    {
        HtmlBody = myModel.Body
    };
    GetAllImgTags(bodyBuilder);
    message.Body = bodyBuilder.ToMessageBody();
    // Send Email Here...
    return "OK"
}

    public string GetAllImgTags(BodyBuilder bodyBuilder)
    {
        HtmlDocument document = new HtmlDocument();

        document.LoadHtml(bodyBuilder.HtmlBody);

        var imgList = document.DocumentNode.Descendants("img").Where(x =>
        {
            string src = x.GetAttributeValue("src", null) ?? "";
            return !string.IsNullOrEmpty(src);
        }).ToList();

        foreach(var item in imgList)
        {
            string currentSrcValue = item.GetAttributeValue("src", null);
            var file = Path.Combine(_env.WebRootPath,"images", currentSrcValue);
            if (File.Exists(file))
            {                    
                byte[] imageData = System.IO.File.ReadAllBytes(file);
                string contentId = string.Format("{0}@{1}", Path.GetFileName(file), Guid.NewGuid().ToString());
                LinkedResource inline = new LinkedResource(new MemoryStream(imageData), Image.Jpeg)
                {
                    ContentId = contentId,
                    TransferEncoding = TransferEncoding.Base64,
                    ContentLink = new Uri("cid:" + contentId),

                };
                inline.ContentType.Name = contentId;
                inline.ContentType.MediaType = Image.Jpeg;
                bodyBuilder.LinkedResources.Add(contentId, new MemoryStream(imageData));

                item.SetAttributeValue("src", "cid:" + contentId);
                inline.Dispose();
            }
        }

        bodyBuilder.HtmlBody = document.DocumentNode.OuterHtml;
        string result = document.DocumentNode.OuterHtml;
        return result;
    }

Answer 1

嗯，首先，为什么要创建 System.Net.Mail 对象然后简单地处理它们而不以任何方式使用它们？

看这段代码了解我的意思：

LinkedResource inline = new LinkedResource(new MemoryStream(imageData), Image.Jpeg)
{
    ContentId = contentId,
    TransferEncoding = TransferEncoding.Base64,
    ContentLink = new Uri("cid:" + contentId),
};
inline.ContentType.Name = contentId;
inline.ContentType.MediaType = Image.Jpeg;

让我们试试这个：

var contentType = new ContentType ("image", "jpeg");
var contentId = MimeKit.Utils.MimeUtils.GenerateMessageId ();
var image = (MimePart) bodyBuilder.LinkedResources.Add (file, contentType);
image.ContentTransferEncoding = ContentEncoding.Base64;
image.ContentId = contentId;

item.SetAttributeValue ("src", "cid:" + contentId);

Gmail 问题 - 使用 MailKit 嵌入图像

Issue with Gmail - Embedded images using MailKit

c#

gmail

mailkit

asp.net-core