Retreiving Linked resources by Id

Question

Greetings,

I'm parsing message in RTF format which was sent from MS outlook 2010. Message contains 2 embedded images.

In HTML body I can see that their source contains some kind of Id:
(img border=0 src="cid:embedded-rtf-attachment-id0@rebex.net")
(img border=0 src="cid:embedded-rtf-attachment-id1@rebex.net")

How can I retreive those images from Linked Resources collection using "cid:embedded-rtf-attachment-id0@rebex.net"?

Can I use MailMessage.Resource[0] and MailMessage.Resource[1] presuming that "cid:embedded-rtf-attachment-id0" and "cid:embedded-rtf-attachment-id1" are indexes from this collection?

Thank you.

Answer 1

Hello

you can retrieve the LinkedResource corresponding to "cid:embedded-rtf-attachment-id0@rebex.net" from the BodyHtml like this:

        MailMessage mail = new MailMessage();
        //...
        mail.Load("mail.eml");
        //...
        foreach (LinkedResource resource in mail.Resources)
        {
            if (resource.ContentId != null && resource.ContentId.Id == "embedded-rtf-attachment-id0@rebex.net") // without "cid:"
            {
                // this is the LinkedResource corresponding to "cid:embedded-rtf-attachment-id0@rebex.net"
                Console.WriteLine(resource.ContentString);
            }
        }

Parsing the index from the Content-ID is definitely not a good idea. So please use the above solution.

Comments

Tomáš, Thank you.

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Tomáš,

Just checked solution you've proposed.

It works fine for mail in HTML format. But it seems this solution didn't work for RTF letters: "resource.ContentId" is null for all RTF attachments.

Could it be mail server or mail client issue? Can you confirm your solution works for RTF mail?

Thank you.

---

Just a little clarifation: Resources are present in collection, but their ContentId is null. So it looks that I'm unable to get specific resource from collection using that way you've proposed.

Answer 2

To make it clear: ContentId of attachments and linked resources is set by the mail client which creates the mail and it can be anything. There is no guarantee about it.

However, Rebex offers a new advanced feature which enables transformation of MS Outlook format messages (which contains no HTML) into more user friendly format. During this proccess, a HTML body is converted from rtf and if there were embedded images, we add ContentId in the special format mentioned above) and reference the images from the HtmlBody.

So a MailMessage which contains "cid:embedded-rtf-attachment-id{index}@rebex.net" within its HtmlBody will definitely contain an image in the mail.Resources collection. The other implication is not valid. The cid has to be in the exact specified format ending with @rebex.net.

Currently only embedded images (jpg, bmp, png or gif) are referenced from the Rebex generated HtmlBody). Other embedded attachments are only referenced in the html textually as <<attachment.filename>> and their ContentId can be null (and you can find them in mail.Attachments).

Comments

Thank you for your answer.