Markdown (Notes) in a report template

[zwvk]

I would like to be able to put the notes associated with a part into my BOM template.

I've naïvely tried adding this:

<div class='main-part-notes'>
    {{ part.notes|markdown }}
</div>

inside the sample bill of material report.html file, InvenTree produces a "Invalid filter: 'markdown'" error when I do this.

[zwvk]

Well, I figured it out with help from Grok

I added a markdown.py file like below to the folder "/home/inventree/src/backend/InvenTree/report/templatetags"

from django import template
import markdown
from django.conf import settings
import os

register = template.Library()

@register.filter
def render_markdown(value):
    html = markdown.markdown(value)
    # Replace relative /media/ paths with absolute file system paths
    media_root = settings.MEDIA_ROOT
    absolute_media_path = f"file://{os.path.abspath(media_root)}/"
    return html.replace('src="/media/', f'src="{absolute_media_path}')

After this the server needed to be restarted.

Then I added a {% load markdown %} as well as this section to the BOM template file

<tr>
    <td>
        <div class='main-part-notes'>
            {{ part.notes|render_markdown|safe }}
        </div>
    </td>
</tr>

Now I can get the notes in my reports, with full Markdown, and image support!

[matmair]

Packaging this as a plugin might make upgrades easier in the future as it removes direct edits in files that we might change at any point.

[SchrodingersGat]

@zwvk there is already internal support for this - I have just made a PR to update the documentation

Basically you can use the following code:

{% load markdownify %}

{{ part.notes | markdownify %}

[zwvk]

@SchrodingersGat This does indeed work for the Markdown, however it doesn't find images in /media/. The example I posted also solved this problem by resolving the paths.

Arguably this could be better solved by having the server be aware of /media/ paths the same way it is aware of /static/ paths. Any thoughts on this?

[matmair]

The file serving setup is also well documented https://docs.inventree.org/en/stable/start/processes/#proxy-server

[SchrodingersGat]

Looking through the django-markdownify source code I don't think that the fact that static files are resolved is intentional. It might be a happy coincidence that the local path to the actual files ./static/... is the same as the relative web URL.

As per your information above - we cannot change the method in which we serve static and media files - for a number of reasons.

The better way to solve this would be to implement a shim layer in the existing "markdownify" tag which finds and replaces /static/ and /media/ image tags and replaces them with the correct path to the file on the filesystem.

[LqdBcnAtWork]

I got a python-markdown extension written and added it to markdownify to replace /media and /static img src tags with file:// URIs to the appropriate locations based on MEDIA_ROOT and STATIC_ROOT.

Currently this is written in settings.py. Which is most definitely the wrong spot.

Where should I move this code to so it can be imported into settings.py and added to the MARKDOWNIFY settings?

Then I can create a pull request with the changes, to be used as desired.

[wolflu05]

You may also want into just appending the Server base url before the /media path.

[LqdBcnAtWork]

You may also want into just appending the Server base url before the /media path.

Your idea inspired me to go digging again, this time into the url_fetcher part of Weasyprint.

By setting a known baseurl, and checking if a url starts with said base, we can then turn relative paths (eg /media) into a file object with open()

File: report/models.py

Anywhere:

from InvenTree import config
from urllib.parse import urlparse, unquote

WE_BASE_URL = "http://localhost"

def url_wrap(url:str, timeout=10, ssl_context=None):
    media = config.get_media_dir().resolve().parent
    static = config.get_static_dir().resolve().parent
    if(url.startswith(WE_BASE_URL)):
        u = unquote(urlparse(url).path)
        if(u.startswith("/media")):
            return {
                "file_obj": open(media.joinpath(u[1:]).resolve(), "rb"),
            }
        elif(u.startswith("/static")):
            return {
                "file_obj": open(static.joinpath(u[1:]).resolve(), "rb"),
            }
    return default_url_fetcher(url, timeout=timeout, ssl_context=ssl_context)

default_url_fetcher is imported from weasyprint

in the ReportTemplateBase.render method

        pdf = HTML(string=html, url_fetcher=url_wrap, base_url=WE_BASE_URL).write_pdf()
        #                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[zwvk]

I'm closing this conversation in favor of this PR #9394