Thread Slack posts

[zachlipton]

The #urlwatch Slack channel is often unreadable because of the volume and format of the bot's posts. Totally-low-priority convenience feature only worth spending time on if you want a diversionary activity, but it would be kind of nice if it printed the summary table at the top and then posted one Slack thread per state, something like:

CHANGED: Alabama ( https://services7.arcgis.com/4RQmZZ0yaZkGR1zy/arcgis/rest/services/COV19_Public_Dashboard_ReadOnly/FeatureServer/0/query?where=CONFIRMED>0&outStatistics=[{"statisticType":"sum","onStatisticField":"CONFIRMED"}]&cacheHint=true )
1 reply

And then the actual diff would be in the "1 reply."

This would require modifying SlackReporter, which currently assumes its getting a big block of text from its superclass and spitting it out. The WebhookReporter that follows it can serve as an example of getting the actual data to format it. It will also require some Slack API work to get the ts value of the parent message and supply that when posting the child.

If you need Slack keys or permissions to test, just let me know.