CMlyst 0.3.0 released

CMlyst is a Web Content Management System built using Cutelyst, it was initially inspired by Wordpress and then Ghost. So it's a mixture of both.

Two years ago I did it's first release, and since them I've been slowly improving it, it's been on production for that long providing web site/blog. The 0.2.0 release was a silent one which marks the transition from QSettings storage to sqlite.

Storing content on QSettings is at first quite interesting since it's easy to use but it showed not suitable very fast, first it kept leaving .lock files, then it's not very fast to access so I had used a cache with all data, and a notifier updated that when something changed on the directory, but this also didn't properly triggered QFileSystemWatcher so once a new page was out the cache wasn't properly updated.

Once it was ported to sqlite, I decided to study how Ghost worked, this was mainly due many Qt/KDE developer switching to it. Ghost is quite simplistic, so it was very easy to try to provide something quite compatible with it, porting a Ghost theme to CMlyst requires very little changes due it's syntax being close to Grantlee/Django.

Due porting to sqlite it also became clear that an export/import tool was needed, so you can now import/export it in JSON format, pretty close to Ghost, actually you can even import all you Ghost pages with it, but the opposite won't work, and that's because we store pages as HTML not Markdown, my feeling about markdown is that it is simple to use, convenient to geeks but it's yet another thing to teach users which can simply use a WYSIWYG editor.

Security wise you need to be sure that both Markdown and HTML are safe, and CMlyst doesn't do this, so if you put it on production be sure that only users that know what they are doing use it, you can even break the layout with a not closed tag.

But don't worry, I'm working on a fix for this, html-qt is a WHATWG HTML5 specification parser, mostly complete, but the part to have a DOM, is not done yet, with it, I can make sure the HTML won't break layout and remove unsafe tags.

Feature wise, CMlyst has 80% of Ghost features, if you like it please help add missing features to Admin page.

Some cool numbers

Comparing CMlyst to Ghost can be trick, but it's interesting to see the numbers.

Memory usage:

  • CMlyst uses ~5MB
  • Ghost uses ~120MB

Requests per second (using the same page content)

  • CMlyst 3500/rps (production mode), 1108/rps (developer mode)
  • Ghost 100/rps (production mode)

While the RPS number is very different, on production you can use NGINX cache which would make the slow Ghost RPS not a problem, but that comes to a price of more storage and RAM usage, if you run on an AWS micro instance with 1GB of RAM this means you can have a lot less instances running at the same time, some simple math shows you could have 200 CMlyst instaces vs 8 of Ghost.

Try it!

Sadly it's also liked soon I'll be forking Grantlee, the lack of maintenance just hit me yesterday (when I was going to release this), Qt 5.7+ has changed QDateTime::toString() to include TZ data which broke Grantlee date filter which isn't expecting that, so I had to do a weird workaround marking date as local to avoid the extra information.