I recently wrote my first chrome extension, Jigoku Game Log.
Jigoku
Jigoku is an excellent online implementation of the excellent card game Legend of the Five Rings. Game events are logged as messages in a chat area in a corner of the page, together with any chat between the players. No game replays are saved.
Jigoku Game Log
Jigoku Game Log goes into the DOM to extract the game events, omits superfluous information like chat messages, summarises and formats important information, and then sends this newly-produced game log to markdownshare.com to be saved for sharing and saving, for either analysis or sharing war stories with comrades.
Challenges
Using const and let gave me errors, so I used var throughout. I guess this might be because the script is constantly ongoing and doesn’t get garbage collected.
Submitting the game log to markdownshare.com through the fetch API was difficult.
First, Chrome doesn’t allow fetch API from most areas in the extension. It needs to be done in the background.js, so message passing needs to be used to get the fetch request to background.js.
Second, I had issues with permissions, with my request not getting sent, with no informative error logs. Turns out, there are several places to add the cross-origin site permissions to.
Third, the API usage example on markdownshare.com showed the use of cURL. What I didn’t realise, what that cURL automatically sends the message with ContentType:application/x-www-form-urlencoded when using the -d option, so I needed to specify this manually with fetch and I also needed to do encodeURIComponent() on the text.
Results
More than 10 users in the L5R community are using the extension 😊.