Parsing multiline headers

[alexanderbluhm]

Hi, first of all thanks for this nice library. I tested some others, but this one provides a lot of things I need. However, there might be an issue with multiline headers. In my mail, I have an attachment that looks like this (sent from iOS Mail App):

--Apple-Mail-97D39683
Content-Type: audio/x-m4a;
name="My Recording.m4a";
x-apple-part-url=B074DA16-AEC2-4B5E-BF19-20B188C3FFF1
Content-Disposition: attachment;
filename="My Recording.m4a"
Content-Transfer-Encoding: base64

However, when I print the parsed message (println!("{:?}", message);, I am not able to see the filename anywhere. I also tried to loop over the attachments and use attachment.attachment_name(). I am migrating from a Python project and there it was no problem parsing the message correctly, so it might be an issue with mail-parser itself.

I used this code to test but I am not able to get the file name from the message object.

Test Code

```rs let input = br#"From: Art Vandelay (Vandelay Industries) To: "Colleagues": "James Smythe" ; Friends: jane@example.com, =?UTF-8?Q?John_Sm=C3=AEth?= ; Date: Sat, 20 Nov 2021 14:22:01 -0800 Subject: Why not both importing AND exporting? =?utf-8?b?4pi6?= Content-Type: multipart/mixed; boundary="festivus"; --festivus Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: base64 PGh0bWw+PHA+SSB3YXMgdGhpbmtpbmcgYWJvdXQgcXVpdHRpbmcgdGhlICZsZHF1bztle HBvcnRpbmcmcmRxdW87IHRvIGZvY3VzIGp1c3Qgb24gdGhlICZsZHF1bztpbXBvcnRpbm cmcmRxdW87LDwvcD48cD5idXQgdGhlbiBJIHRob3VnaHQsIHdoeSBub3QgZG8gYm90aD8 gJiN4MjYzQTs8L3A+PC9odG1sPg== --festivus Content-Type: message/rfc822; name="Exporting my book about coffee tables.eml" Content-Disposition: inline; filename="Exporting my book about coffee tables.eml" Content-Transfer-Encoding: 7bit From: "Cosmo Kramer" Subject: Exporting my book about coffee tables Content-Type: multipart/mixed; boundary="giddyup"; --giddyup Content-Type: audio/x-m4a; name="My Recording.m4a"; x-apple-part-url=B074DA16-AEC2-4B5E-BF19-20B188C3FFF1 Content-Disposition: attachment; filename="My Recording.m4a" Content-Transfer-Encoding: base64 =FF=FE=0C!5=D8"=DD5=D8)=DD5=D8-=DD =005=D8*=DD5=D8"=DD =005=D8"= =DD5=D85=DD5=D8-=DD5=D8,=DD5=D8/=DD5=D81=DD =005=D8*=DD5=D86=DD = =005=D8=1F=DD5=D8,=DD5=D8,=DD5=D8(=DD =005=D8-=DD5=D8)=DD5=D8"= =DD5=D8=1E=DD5=D80=DD5=D8"=DD!=00 --giddyup Content-Type: image/gif; name*1="about "; name*0="Book "; name*2*=utf-8''%e2%98%95 tables.gif Content-Transfer-Encoding: Base64 Content-Disposition: attachment R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 --giddyup-- --festivus-- "#; let message = Message::parse(input); println!("{:?}", message); ```

Would be great if this could be resolved :)

[mdecimus]

In my mail, I have an attachment that looks like this (sent from iOS Mail App):

Your sample message is missing a space or tab character on the line wraps, it should be like this:

--Apple-Mail-97D39683
Content-Type: audio/x-m4a;
   name="My Recording.m4a";
   x-apple-part-url=B074DA16-AEC2-4B5E-BF19-20B188C3FFF1
Content-Disposition: attachment;
   filename="My Recording.m4a"
Content-Transfer-Encoding: base64

The attachment_name() method should be called on the MimePart that contains the attachment, it won't work when called from Message (unless the message consists of just one attachment and no body).

[alexanderbluhm]

@mdecimus Thanks for the quick answer! I am doing this, similar to your example:

for attachment in message.attachments() {
    if !attachment.is_message() {
        let filename = attachment.attachment_name().unwrap_or("Untitled");
        let contents = attachment.contents();

But the filename is "Untitled", so the fallback.

[mdecimus]

Try iterating &message.parts.

[alexanderbluhm]

Hi @mdecimus I tried this:

for part in &message.parts {
    match part.attachment_name() {
        Some(name) => {
            println!("Disposition: {:?}", name);
        }
        None => {
            println!("No name");
        }
    }
}

but all I get is "No name" four times. I also tried to access content_disposition() but also there I can't get the filename. Any idea? 🤔

[mdecimus]

Can you include the original message? You can remove any sensitive information, I'd just like to see the MIME headers.

[alexanderbluhm]

@mdecimus Thanks for your help. I exported the mail body using

match connection.retrieve(info.message_id, &mut buffer) {
    Ok(_) => {
        let text = std::str::from_utf8(&buffer).unwrap();
        fs::write("mail.txt", text).expect("Unable to write file");

Here is the mail.txt export of the mail.

[mdecimus]

The problem is that spaces are missing on the multiline headers:

--Apple-Mail-97D39683-EA28-4F27-BCF8-B7C99849500A
Content-Type: audio/x-m4a;
name="Neue Aufnahme 7.m4a";
x-apple-part-url=B074DA16-AEC2-4B5E-BF19-20B188C3FFF1
Content-Disposition: attachment;
filename="Neue Aufnahme 7.m4a"
Content-Transfer-Encoding: base64

Add the missing spaces and it should work:

--Apple-Mail-97D39683-EA28-4F27-BCF8-B7C99849500A
Content-Type: audio/x-m4a;
  name="Neue Aufnahme 7.m4a";
  x-apple-part-url=B074DA16-AEC2-4B5E-BF19-20B188C3FFF1
Content-Disposition: attachment;
  filename="Neue Aufnahme 7.m4a"
Content-Transfer-Encoding: base64

[alexanderbluhm]

@mdecimus Thanks. The data is coming from rust_pop3_client, could it be that the lib messes up the spaces? Anyway I will check if the error occurs using another lib.

[mdecimus]

It could be, something is breaking that message. Spaces are required on multi line headers otherwise they are parsed as a new header.

[alexanderbluhm]

Used another lib and it's working now 🎉