Source of https://www.mathdown.net

Online collaborative markdown with math. Main features:

• Markdown is styled in-place, no source/preview separation.
• Edits are synced in real time.
• Access control is simply by sharing the secret URL. No sign up needed to collaborate.
• LaTeX-syntax formulas rendered in-place when cursor is outside formula.

Powered by CodeMirror, MathJax and Firebase's Firepad. I'm using "CM" = CodeMirror, "MJ" = MathJax abbreviations a lot in the project.

Alpha quality – will eat your math, burn your bookmarks & expose your secrets. I mean it. See for example #85 — saving would sometimes be silently broken, for half a year! I'm working to make it more robust (and tested) but for now, be careful.

Issues:

License

My code is under MIT License. Exception: font/ contains a subsetted Bitstream Charter font under a permissive license - see fonts/LICENSE.

Dependencies:

• CodeMirror is also MIT.

• MathJax is under Apache License 2.0.

• My CodeMirror-MathJax glue is also MIT.

• The collaborative editor Firepad is MIT. It calls firebase javascipt API.

• Firebase is a proprietary service; their client-side javascipt API firebase.js is also proprietary, though apparently fine to distribute in practice — (#4). [firbease.js has been accidentally MIT-licensed for a time but I've upgraded to newer versions so this doesn't apply.]

  I'm not including firebase.js directly but using it as a git submodule.

Document hosting and privacy(?) on Firebase

All user data is stored in Firebase, now owned by Google. Their privacy policy. Documents access (read AND edit) is by secret document id which is part of the url. This is grossly unsecure unless using HTTPS.

The downside is users can't really control their data. Running a "self-hosted" copy of the site still leaves all data in the hands of Firebase. See #4 for more discussion.

The upside is all forks interoperate; you can change the design or tweak the editor and still access same documents. E.g. https://mathdown.net/index.html?doc=demo and http://rhythmus.be/mathdown/index.html?doc=demo look different but access the same doc -- and real-time collaboration between them works!

I'm so far on the free Firebase plan - 100 devices (not sure if 1:1 with users), 1GB Data Storage (used < 100MB). => Will need 49USD/mo plan as soon as I get non-negligible usage. https://console.firebase.google.com/u/0/project/firebase-mathdown/usage (only visible to me)

Deletion is impossible

The current Firebase security rules make document history append-only. That's a nice safety feature but it means that once a document's URL gets out, it's full history is forever accessible to the the world. This must change eventually (#92).

Browser support

Basically whatever CodeMirror supports: IE8+ and about everything else. But mobile is currently almost unusable (#81).

JavaScript is required (and this includes running the non-Free firebase.js in your browser). You can't even read documents without JavaScript; reading won't be hard to fix (#7) — but editing documents without JavaScript is implausible (I plan to settle for append-only form).

Cookies

The only cookies I'm aware of:

• mjx.menu cookie set for a year(?) if you manually change MathJax settings.

I'm not sure Firebase never sets cookies. Things would change if I implement login (#50).

Installing dependencies

1. After checking out, run this to materialize client-side dependencies:

   git submodule update --init --recursive

Append --remote to upgrade to newest versions of all submodules (need to commit afterwards if anything changed). Known constraints on updating all deps:

* firepad only includes pre-built dist/firepad.js in tagged versions (after every release they strip it back).
* [CodeMirror-MathJax currently doesn't support MathJax 2.5](https://github.com/cben/CodeMirror-MathJax/issues/33).

(I'm directly working in gh-pages branch without a master branch. GH Pages automatically resolves https://... submodules. It's no longer the primary hosting but it's still useful to test the static version works.)

2. To install server-side dependencies (and devDependencies) listed in package.json run:

   npm install
   

(But when deploying to RHcloud or Heroku, npm install might run in --production mode and devDependencies won't be available.)

To see whether any updates are needed/possible, run npm outdated. To update run:

npm update --save
npm shrinkwrap

Then commit the new `package.json` and `npm-shrinkwrap.json`.

Test(s)

test/browser-on-saucelabs.spec.coffee runs tests on several browsers using free browser testing courtesy of Sause Labs. There are pathetically few tests.

To run the tests:

npm install  # once
npm test

To run only some tests and/or browsers, use:

./node_modules/.bin/mocha --grep firefox

The test runs automatically on any commit and pull request. TODO: This project was set up on Travis-CI but it's no longer open-source friendly (#216).

Where it's deployed and how to run your fork

This app works as pure static pages, and I intend to keep it this way. However, opening index.html as file: URL no longer works, you do need an http server. The main deployment currently runs on Netlify.

However you run it — locally or prod — you can open the same document ids (doc=...) and real-time collaboration will work!

• Run local server (server.coffee):

  npm install  # once
  npm start    # Prints URL you can click
  

  (you can choose a port by setting PORT env var. Ctrl+C when done.)

  Or use any other static server e.g. python3 -m http.server

• Github Pages serves the gh-pages branch at https://cben.github.io/mathdown.

  • If you fork this repo, you can immediately use your version at https://YOUR-GITHUB-USERNAME.github.io/mathdown/! Or maybe not immediately but after you push something.

• Pull requests should get Netlify previews.

• You could also setup your own Netlify for your fork.

(Services like https://raw.githack.com/ would be handy but don't support submodules afaict.)

https://httpbin.dev

P.S. deployment/ subdirectory documents obsolete details of prior hostings (Heroku, OpenShift, TLS stuff).

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Other things called "mathdown":

• https://mathdown.app/ — markdown editor for Mac, iPad, iPhone. LaTeX formula rendering, but also "REPL" blocks for some interactive computations (numeric & symbolic).
• https://github.com/mayoff/Mathdown/tree/mathjax — Markdown.pl hacked for MathJax pass-through
• https://github.com/keishi/kernlog/blob/master/markdown/extensions/mathdown.py — math in python-markdown, part of "Yet another blog for google app engine"
• http://kwkbtr.info/log/201010050320 — a way to combine Showdown + Mathjax
• https://gitlab.com/padawanphysicist/tw5-mathdown/tree/master — Math (via TeXZilla) + Markdown-it in TiddlyWiki5
• https://github.com/domluna/mathdown — Watches markdown files, converts to HTML with KateX.
• https://github.com/jirkalewandowski/mathdown — heuristically recognizes LaTeX formulas in text with no delimiters.

I should really talk to these folk whether it's OK that I'm using the name and the domain...

• http://www.urbandictionary.com/define.php?term=mathdown