Feature request: call out new subs

[rakslice]

Kate was talking about the idea of the bot calling out new subs in chat, like the mods are doing now.

Related APIs:

• New sub notifications appear as message from twitchnotify
• Subscriber info by request https://github.com/justintv/Twitch-API/blob/master/v3_resources/subscriptions.md

[rakslice]

Not sure if the general twitch user wrath for bot greetings would extend to sub messages: https://www.reddit.com/r/Twitch/comments/2hvw97/how_do_i_make_nightbot_welcome_people_to_stream/

[rakslice]

I've put together a PoC of this in https://github.com/rakslice/kaet/tree/on_sub_message.

Suggestions appreciated:

• This uses golang text/template for chat messages, which is too complicated; simpler plain-text templating system wanted.
• More template fields needed?
• Basic template errors are detected when the message is set; not sure if any of the possible error message contents are a security issue; this may change if the template library changes

Usage

Set sub message:

<delta__vee> !seteventmessage newsub Hi {{.Username}}! Welcome to the channel! You are sub #{{NumberOfSubs}}!
<@ee__vee> ​Message for newsub set.

...

<@ee__vee> ​Hi testuser! Welcome to the channel! You are sub #42!

Test sub message:

<delta__vee> !testeventmessage newsub joebat
<@ee__vee> ​hi joebat! welcome to the channel

Remove sub message

<delta__vee> !removeeventmessage newsub
<@ee__vee> ​Message for newsub removed.

Useful error messages

<delta__vee> !seteventmessage foo hello world
<@ee__vee> ​There's no event 'foo'. Available events: newsub
<delta__vee> !removeeventmessage foo
<@ee__vee> ​There is already no message for foo
<delta__vee> !seteventmessage newsub {{test}}
<@ee__vee> ​Template error: template: newsub:1: function "test" not defined
<delta__vee> !seteventmessage newsub {{{what}}
<@ee__vee> ​Template error: template: newsub:1: unexpected "{" in command