I tried to write my first plugin starting from scratch and imitating (almost copying) the https://github.com/a5mith/nodebb-plugin-youtube-lite plugin. I changed it so it can embed steam game information on a post based on the url of the game with the following syntax :
<iframe src="http://store.steampowered.com/widget/242680/" frameborder="0" width="646" height="190"></iframe>
the number being relative to a given game.
The substitution takes place on the post, but nothing shows up. Here is the test plugin :
And here is the post where it does not show up (sorry for the strange port number, but the normal one is used by the production forum) :
Searching on this forum for a similar issue, this topic showed up but did not helped me much :