Five ways to extend edX

(Originally written by Sef (sef@stanford.edu), transcribed by Ned)

Five Ways to Extend edX

I can think of five ways that someone could extend edX. Here they are in order of difficulty:

1. jsinput -- Create a "Custom JavaScript Grade and Display" component, and then provide JS with getState(), setState(), and getGrade() methods.
2. LTI -- edX supports LTI 1.1 now, LTI 2.0 in development
3. custom grader -- Code can be run on an external server to do arbitrary work to grade problems.
4. XBlock
5. hack on core code

Here’s my initial attempt at a grid to summarize , but I’m sure there are more rows that we’d want to consider:

	JSInput	LTI	Grader	XBlock	Core Mod
Cost	Low	Low	Med	Med	High
Language	JS	any	any	Python	Python
Need dev environment	no	no	yes	yes	yes
Self-host component	no	yes	yes	no	no
Need edX involvement	no	no	yes	yes	yes
Clean UI integration	yes	no [1]	yes	yes	yes
Mobile friendly	no	maybe	yes	yes	yes
Server Side Grading	no	yes	yes	yes	yes
Usage Data	no [2]	no	limited	yes (?)	yes

Notes:

• [1] Only LTI components delivered via https can be iframed in Many are served over http only. And even then they usually have their own look and feel. For example, Piazza can be iFramed in, but has its own navigation elements and their color scheme (see http://networking.class.stanford.edu/ for an example).
• [2] JSInput really only exposes the getState, putState, getGrade methods. But is there any reason why we can’t also document / publish the tracking endpoint (/events/user_track I believe)