1633982 - Allow ignoring the MIME Content-Type of file attachments in received emails when choosing applications to open file attachments

Status: RESOLVED INVALID

(Thunderbird :: Untriaged, enhancement)

Description

[KU]

Attachment: 2mails.zip contains 2 EML files

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.122 Safari/537.36

Steps to reproduce:

1. Open TB_1.dxf attachment file attached at received mail.

Actual results:

Case 1: "Sample dxf (text).eml"

• Prompt to ask open or save as: Text Document (84.4 KB)

Case 2: "Sample dxf (not text).eml"

• Prompt to ask open or save as: DWG TrueView Drawing Interchange (84.4 KB)

Expected results:

• In both cases, I want to open "TB_1.dxf" with application associated with ".dxf" extension.

Comment 1

[Andre Klapper]

The behavior is exactly what the "Content-Type" in your emails defines. Open the two emails with a text editor and see:

$:acko\> grep -r -B2 -A2 "Content-Transfer-Encoding: base64" Sample\ dxf\ \(*.eml
Sample dxf (not text).eml-Content-Type: application/dxf;
Sample dxf (not text).eml- name="TB_1.dxf"
Sample dxf (not text).eml:Content-Transfer-Encoding: base64
Sample dxf (not text).eml-Content-Disposition: attachment;
Sample dxf (not text).eml- filename="TB_1.dxf"
--
Sample dxf (text).eml-Content-Type: text/plain; charset=UTF-8;
Sample dxf (text).eml- name="TB_1.dxf"
Sample dxf (text).eml:Content-Transfer-Encoding: base64
Sample dxf (text).eml-Content-Disposition: attachment;
Sample dxf (text).eml- filename="TB_1.dxf"

There is no bug in Thunderbird.

Comment 2

[KU]

Thanks for checking this!

The behavior is exactly what the "Content-Type" in your emails defines. Open the two emails with a text editor and see:

Yes. As you have confirmed, the behavior depends on "Content-Type" definition decided by mail Sender, not me and not our Thunderbird.

So I'm happy if there is a workaround that I can open this file by its extension '.dxf' instead of designated mediaType.

Comment 3

[Andre Klapper]

I can imagine that this depends on the underlying operating system which offers that prompt to ask "open or save as", and if that dialog offers to choose a random application to open some file? (Sorry, I have not used Microsoft Windows for many years so I don't know that dialog)

Comment 4

[KU]

Hi thanks for looking at this!
I have written this situation in one picture, it will help to know what happens...

https://i.imgur.com/6UIgRAB.png

Comment 5

[Andre Klapper]

In the "Thunderbird confirmatnion popup", choose "Other..." in the dropdown and choose the correct application.

Comment 6

[KU]

Thanks, I have proceeded as you suggested.

In the "Thunderbird confirmatnion popup", choose "Other..." in the dropdown and choose the correct application.

It couldn't open. error message: https://i.imgur.com/kbcrLbB.png

DWG TrueView Message

Cannot find specified drawing file.
Please verify that the file exists.

[OK]

I knew why...

Thunderbird automatically attaches file extension .txt to the text file which I'm going to open. It is like: ...\Temp\TB_1.dxf-3.txt

https://i.imgur.com/dkoPcX2.png

Comment 7

[KU]

Thanks.
I have confirmed that this issue has been radically resolved in Thunderbird 91.4.1

Bug 1729632 - Temporary file during mail transfers are sometimes not in the correct extensions