Displaying Mermaid Diagrams in a Jupyter Notebook Using Python

mermaid.ipynb

test.mmd

thanks

To do it in SVG instead which gives more visually-pleasing results:

import base64
from IPython.display import display_svg
from urllib.request import Request, urlopen

def mm(graph):
    graphbytes = graph.encode("ascii")
    base64_bytes = base64.b64encode(graphbytes)
    base64_string = base64_bytes.decode("ascii")
    url="https://mermaid.ink/svg/" + base64_string
    req=Request(url, headers={'User-Agent': 'IPython/Notebook'})
    display_svg(urlopen(req).read().decode(), raw=True)

More information can be found at https://gist.github.com/diraneyya/1177344d2ead2185c0316f8b5f6ef67b

I have to say that this is the first time I learn that .mmd is rendered as a Mermaid diagram in GitHub. I know that .md files do not support Mermaid in Gists which is why this is actually very useful. I am also pleased to see that there are two files in this Gist, which illustrates that Gists are actually just git repositories. Thank you!

Does display_svg(..., raw=True) work well for you?
In Jupyter sure, but most ways I tried of embedding SVG into notebook don't render well on NBViewer/GitHub/GitLab/both. Images linking to src="https://mermaid.ink/..." is fine, it's the actually embedding the image into .ipynb that's giving me trouble. [old man yelling at cloud]

• Disabling %%{init: { "htmlLabels": false, "flowchart": { "htmlLabels": false } } }%%, when possible, generally makes SVG more compatible. Not enough — before / after — but hopefully more future-proof.
• NBViewer issue, looks like GitHub uses ≈same code? GitLab OTOH renders SVG practically fine 👍
• With current JupyterLab (4.4.3), I don't even need external conversion services! Turns out that emitting "text/vnd.mermaid" MIME type not only renders locally, but adds back the SVG representation to the cell, and saves that to .ipynb ✨
  Combined with GitLab hosting, is closest I found to the holy grail of locally authorable & locally viewable & easy to share notebooks.
  https://gitlab.com/cben/sandbox/blob/6bdb770ff0a64e5187eed927b71ef866c056e70d/jupyter_notebook/mermaid_mime_type.ipynb (using display() for side-effect output), https://gitlab.com/cben/ipywm-notes/-/blob/8bc4e93498af3371ee04e8c899b2ae23e8296d5c/HANDOFF.ipynb (a Mermaid class with rich repr + magic).
• ```mermaid fenced blocks render fine in markdown files on GitHub/GitLab — but not yet in markdown notebook cells.
  For now, splitting diagrams to separate code cells is best solution I found :-/ Unfortunately, "Collapse code" to hide the diagram source in Jupyter is NOT honored by GitLab rendering.
• GitLab renders SVGs with pretty low height; scrollable but it doesn't know the "true" size of the diagram, cause it sticks it in an iframe 🙈.
  Ooof, those mermaid.ink external images are maybe not so bad? 😜
  🤔 personally, I'll take the imperfect-yet-working GitLab as good enough; people who want better view can clone & open notebook locally...