Send multiline messages to slack

[chrisBrookes93]

Update pmxbot webhook endpoint to join newlines and send message to slack once, to allow posting multi-line strings to slack and reduce chances of API throttling (which we're seeing quite a lot these days). The previous code had a comment that said "We must send line-by-line, so split multiline messages" which has been there since the beginning (I checked the git history). However according to the slack docs (https://api.slack.com/reference/surfaces/formatting#line-breaks), newline characters in messages are supported. I'm thinking this was an edge case/limitation of the slack API years ago. If there was specific reasoning why we are splitting lines then please share :)

I've tested this and verified it as working...

Before:

After:

Test script used:

import requests
message = "My Shopping List:\n- Cheese\n- Butter\n- Milk"
url = "http://localhost:8080/chris.brookes"
resp = requests.post(url, data=message)

Please inform me if there are other edge cases in the API that I haven't considered!

[chrisBrookes93]

Hey @jaraco, please take a look at this when you have capacity. Thanks!

[jaraco]

I'm on mobile now. I'll add a news entry and merge+release later (likely today).

[jaraco]

It's quite possible (likely) this limitation has existed since before Slack, when IRC was the main server, or when pmxbot relied on Slack's IRC gateway for communication. It's possible that adding this change will now break on IRC servers, but I think that's okay. If it does in fact break, and there's an IRC user out there who cares, they'll report it and we'll fix the issue in pmxbot (by adding multiline handling in the pmxbot.irc implementation).

[adriandiazgar]

Thanks @jaraco