class BBS::DiscordWebhook

Posts messages to a Discord channel through its webhook URL. Plain Ruby with no other part of the gem, so a board’s domain can use it without the telnet server:

require 'bbs/discord_webhook'

discord = BBS::DiscordWebhook.new(ENV['DISCORD_WEBHOOK'], label: 'feedia: Discord')
discord.post("📨 **#{BBS::DiscordWebhook.escape(name)}** wrote to the admins")

A post goes out in a thread of its own, so a slow webhook never stalls a call. Mentions are off (a caller cannot ping @everyone), the content is cut at max characters, and at most relay_max posts go out in relay_window seconds, however many callers post, so a crowd cannot flood the channel: the rest are dropped and logged. Errors and answers other than 2xx are logged (BBS.log, with label as the tag), never raised. Without a URL (nil or empty) it is off and posts nothing.

Constants

MARKDOWN: The characters of Discord’s markdown (and @), which ::escape escapes.
MAX: The default most characters of a post’s content (Discord takes 2000).
RELAY_MAX: The default most posts in a RELAY_WINDOW.
RELAY_WINDOW: The default window of the relay limit, in seconds.
SUPPRESS_EMBEDS: The message flag that turns off the link previews (embeds).
TIMEOUT: The default seconds to wait for the connection and for each read and write.

Attributes

uri [R]

The webhook’s URI, or nil when it is off.

Public Class Methods

clip (text, limit)

Source

# File lib/bbs/discord_webhook.rb, line 45
def self.clip(text, limit)
  flat = text.to_s.gsub(/\s+/, ' ').strip
  flat.length > limit ? "#{flat[0, limit]}…" : flat
end

text on one line (runs of whitespace one space, stripped), cut to limit characters with an ellipsis after. Not escaped.

escape (text)

Source

# File lib/bbs/discord_webhook.rb, line 41
def self.escape(text) = text.to_s.gsub(MARKDOWN) { "\\#{Regexp.last_match(1)}" }

text with Discord’s markdown characters (and @, links included) backslash-escaped, so a caller’s text shows as typed.

new (url, max: MAX, relay_max: RELAY_MAX, relay_window: RELAY_WINDOW, embeds: true, timeout: TIMEOUT, label: 'Discord')

Source

# File lib/bbs/discord_webhook.rb, line 64
def initialize(url, max: MAX, relay_max: RELAY_MAX, relay_window: RELAY_WINDOW, embeds: true,
               timeout: TIMEOUT, label: 'Discord')
  @uri          = url.to_s.empty? ? nil : URI(url.to_s)
  @max          = max
  @relay        = relay_max && RateLimit.new(limit: relay_max, per: relay_window)
  @embeds       = embeds
  @timeout      = timeout
  @label        = label
end

Creates a webhook client for url (a String or URI; nil or empty: off).

max: the most characters of a post’s content
relay_max: the most posts in relay_window seconds; nil for no limit
relay_window: the window of the relay limit, in seconds
embeds: false to post with SUPPRESS_EMBEDS: no link previews
timeout: seconds to wait for the connection, and for each read and write
label: the tag of its BBS.log lines

Public Instance Methods

enabled? ()

Source

# File lib/bbs/discord_webhook.rb, line 75
def enabled? = !@uri.nil?

Whether it has a URL to post to.

post (content)

Source

# File lib/bbs/discord_webhook.rb, line 82
def post(content)
  return unless enabled?
  return BBS.log(@label, 'relay limit reached, not sent') unless @relay.nil? || @relay.allow?(:posts)

  body = { content: content.to_s[0, @max], allowed_mentions: { parse: [] } }
  body[:flags] = SUPPRESS_EMBEDS unless @embeds
  payload = JSON.generate(body)
  Thread.new { deliver(payload) }
end

Posts content (cut at max) in a background thread, mentions off. Thread-safe.

Returns the Thread (join it to wait for the post), or nil when the webhook is off or the relay limit is reached (logged).