Visual editor

VIDEO (47 min.) with James Forrester - Product Manager and Roan Kattouw - Sr. Software Engineer presenting Jan 13, 2014 at Linux.conf.au on the contentEditable aspects of the system.

The Visual Editor for MediaWiki relies on the Parsoid extension ^[1] AND the Parsoid service. The Parsoid service is a node.js server that interacts with the mediawiki API.

"Parsoid implements a bidirectional wikitext parser and interpreter. It converts and interprets wikitext into an annotated HTML DOM, which can then be edited with HTML editor tools such as the Visual Editor. It also provides the conversion of a (possibly modified) HTML DOM back to wikitext."

Robin Cover would be proud. It round-trips wiki to HTML + RDFa and back.

Installation

You'll need at least MediaWiki v1.23. I personally run the same version that they're running on mediawiki.org (1.24wmf3 greg.rundlett (talk) 19:39, 9 May 2014 (UTC))

WebFaction

To install the Visual Editor extension in a Webfaction account, you need to first have node installed and working. You can do this by using the installer in your webfaction panel and associating a path with the app for a domain. I chose to install 'node' (which is now it's own one-click install). Once you do that you can visit the path you configured for node and you should see the "hello world" app that the installer puts in place. You'll need to stop that app, plus remove the cron job that respawns it. Then, in order to reserve and associate a port for the service, you install another 'app'. You do not need to open this port in the firewall unless you plan to share it with other instances, since HTTP talks to the node server on the backend. (I had to export the PORT, but this is no longer necessary if you configure it in localsettings.js.) Depending on the resource constraints of your hosting package, you may need to limit the number of workers spawned by the Parsoid service. It calculates a number based on the number of processors. For a shared hosting account, this is guaranteed to exceed your RAM or CPU limits, so specify the --num-workers option unless you're running on a dedicated host or VM.

Follow the installation instructions, and remember to edit both LocalSettings.php and localsettings.js When you setup the "interwiki" link to point to your API endpoint, you can choose pretty much whatever name you want to give it. The example is 'localhost'.

You'll want to set/update your $NODE_PATH and $PATH environment variables to locate the installed node modules, and to find the node and npm binaries

export NODE_PATH="$HOME/webapps/node/lib/node_modules:$NODE_PATH"
echo 'export NODE_PATH="$HOME/webapps/node/lib/node_modules:$NODE_PATH"' >> $HOME/.bashrc
which npm
export PATH="$HOME/webapps/node/bin:$PATH"
echo 'export PATH="/$HOME/webapps/node/bin:$PATH"' >> $HOME/.bashrc

Once node (and npm) is available, you of course need to get the parsoid and visual_editor extensions. A quick npm install in the parsoid directory sets up all the node machinery.

To have it run continuously, you might want to use the 'forever' module:

npm install -g forever

But that is just a node way of monitoring processes. You might want to simply use tools built for the purpose like tmux or screen plus monit. If using forever, then you just prefix your call to node with 'forever'

At this point you're ready to run the node server. Note: while installing this, I found a bug which prevented the server from listening on the configured port. It was awesomely cool that I mentioned the bug in IRC #mediawiki-parsoid and it was fixed before I was done testing my installation!!

cd ~/webapps/wiki/extensions/Parsoid/
node api/server.js --num-workers=2 &

The console should print out a list of worker pids, and the port number that the server is listening on. In your web browser, if you visit that path and port (setup in your WebFaction node mapping), you should see the Parsoid web service API message.

There is no stop script for a shared host, but you should be able to do something like

for pid in $(/sbin/pidof `which node`); do kill -9 $pid; done

That's because node is installed under your user account, and the $PATH is set as above to find that instance of node. To be sure that you're not going to kill everyone's node instances, you could look at all the nodes with ps -ef