Defer to discord for disabling at-everyone in webhooks (#497)

Discord already has permissions for whether the bot can ping everyone,
and the webhook send method has a `disableEveryone` option, so let's
defer to the inbuilt Discord permission for this.

When permissions can't be found (shouldn't happen), defaults to
disabling the pings.

Fixes #494

Author: Throne3d

lib/bot.js

@@ -555,12 +555,18 @@ class Bot {
     const webhook = this.findWebhook(channel);
     if (webhook) {
       logger.debug('Sending message to Discord via webhook', withMentions, channel, '->', `#${discordChannel.name}`);
+      const permissions = discordChannel.permissionsFor(this.discord.user);
+      let canPingEveryone = false;
+      if (permissions) {
+        canPingEveryone = permissions.has(discord.Permissions.FLAGS.MENTION_EVERYONE);
+      }
       const avatarURL = this.getDiscordAvatar(author, channel);
       const username = _.padEnd(author.substring(0, USERNAME_MAX_LENGTH), USERNAME_MIN_LENGTH, '_');
       webhook.client.sendMessage(withMentions, {
         username,
         text,
-        avatarURL
+        avatarURL,
+        disableEveryone: !canPingEveryone,
       }).catch(logger.error);
       return;
     }

test/bot.test.js

@@ -986,6 +986,7 @@ describe('Bot', function () {
       username: 'n_',
       text,
       avatarURL: null,
+      disableEveryone: true,
     });
   });
 
@@ -999,6 +1000,48 @@ describe('Bot', function () {
       username: '12345678901234567890123456789012',
       text,
       avatarURL: null,
+      disableEveryone: true,
+    });
+  });
+
+  it('does not ping everyone if user lacks permission', function () {
+    const newConfig = { ...config, webhooks: { '#discord': 'https://discordapp.com/api/webhooks/id/token' } };
+    const bot = new Bot(newConfig);
+    const text = 'message';
+    const permission = discord.Permissions.FLAGS.VIEW_CHANNEL
+      + discord.Permissions.FLAGS.SEND_MESSAGES;
+    bot.discord.channels.get('1234').setPermissionStub(
+      bot.discord.user,
+      new discord.Permissions(permission),
+    );
+    bot.connect();
+    bot.sendToDiscord('nick', '#irc', text);
+    this.sendWebhookMessageStub.should.have.been.calledWith(text, {
+      username: 'nick',
+      text,
+      avatarURL: null,
+      disableEveryone: true,
+    });
+  });
+
+  it('sends @everyone messages if the bot has permission to do so', function () {
+    const newConfig = { ...config, webhooks: { '#discord': 'https://discordapp.com/api/webhooks/id/token' } };
+    const bot = new Bot(newConfig);
+    const text = 'message';
+    const permission = discord.Permissions.FLAGS.VIEW_CHANNEL
+      + discord.Permissions.FLAGS.SEND_MESSAGES
+      + discord.Permissions.FLAGS.MENTION_EVERYONE;
+    bot.discord.channels.get('1234').setPermissionStub(
+      bot.discord.user,
+      new discord.Permissions(permission),
+    );
+    bot.connect();
+    bot.sendToDiscord('nick', '#irc', text);
+    this.sendWebhookMessageStub.should.have.been.calledWith(text, {
+      username: 'nick',
+      text,
+      avatarURL: null,
+      disableEveryone: false,
     });
   });
 

test/stubs/discord-stub.js

@@ -29,6 +29,9 @@ export default function createDiscordStub(sendStub, discordUsers) {
       }, textChannel);
       const textChannelObj = new discord.TextChannel(guild, textChannelData);
       textChannelObj.send = sendStub;
+      const permissions = new discord.Collection();
+      textChannelObj.setPermissionStub = (user, perms) => permissions.set(user, perms);
+      textChannelObj.permissionsFor = user => permissions.get(user);
       this.channels.set(textChannelObj.id, textChannelObj);
       return textChannelObj;
     }