Deal with attachments in Markdown cells

[mtrbean]

Attachment image not showing up when writing content with jupyter notebook

This was originally reported in jupyter-book/jupyter-book#321. Apparently it was working back then but I couldn't get it working with the latest version of jupyter-book.

(The attachment is showing correctly if I generate an html directly using nbconvert jupyter nbconvert mynotebook.ipynb)

To Reproduce

Include an attachment in a markdown cell in a jupyter notebook, for example by pasting an image directly into the cell:

![Example Set 1](attachment:55e982a2-ff6d-4b22-ab40-ae563e0fb0a3.png)

and then build the project. Opening in browser will see a broken image:

Expected behavior

image is displayed in the html

Environment

• Python: 3.7.6
• jupyter-book: 0.7.4
• nbconvert: 5.6.1
• Operating System: linux

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[chrisjsewell]

heya @mtrbean no IIRC we do not currently deal with attachments, I'm going to move this issue to myst-nb

[ajz34]

Hey Eric,
I found this issue when I were dealing other attachment problems :-)
Maybe change png file inclusion code to the following?

![Example Set 1](55e982a2-ff6d-4b22-ab40-ae563e0fb0a3.png)

i.e. attachment: may not be included. Otherwise warning info may come (The warning info comes from my project):

WARNING: image file not readable: Project_01/attachment:assets/acetaldehyde.png

[mtrbean]

@ajz34 The warning does go away by removing attachment:, however it still results in a broken image in the browser. In fact it thinks that 55e982a2-ff6d-4b22-ab40-ae563e0fb0a3.png exists as an asset in the same relative location as the html document. I think when ipynb files are parsed and attachments are encountered, they should should be exported as an actual file like matplotlib chart in cell outputs.

[jaymefosa]

Has anyone found a fix for this yet?

[chrisjsewell]

not just yet I'm afraid, requires a number of changes:

1. The attachments need to be extracted from the notebook, into the build folder
2. ensure links with the attachments: prefix are not treated as external links (URLs)
3. Add some form of transform/logic to tie the reference to the file

It do-able, but not trivial

[jaymefosa]

Alright thanks for the update.

I'd just like to add that videos opened using:

from IPython.display import Video

Video("test.mp4")

Also aren't moved to the build content

[chrisjsewell]

Also aren't moved to the build content

That is because the video is not actually stored in the notebook like other media:

   "outputs": [
    {
     "data": {
      "text/html": [
       "<video src=\"file_example_MP4_480_1_5MG.mp4\" controls  >\n",
       "      Your browser does not support the <code>video</code> element.\n",
       "    </video>"
      ],
      "text/plain": [
       "<IPython.core.display.Video object>"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],

You would have to somehow know to look for videos in html, parse it to get the path, etc.
Thats is really not trivial lol 😬

But yeh we are always happy to accept PRs If anyone wants to give it a go 😄