Add mute rules

app/models/mute_rule.rb

@@ -0,0 +1,7 @@
+class MuteRule < ApplicationRecord
+  belongs_to :user
+
+  def applies_to?(post)
+    !!(post.content =~ /\b#{muted_phrase}\b/i)
+  end
+end

app/workers/question_worker.rb

@@ -9,9 +9,12 @@ class QuestionWorker
   # @param question_id [Integer] newly created question id
   def perform(user_id, question_id)
     user = User.find(user_id)
+    question = Question.find(question_id)
 
     user.followers.each do |f|
-      Inbox.create(user_id: f.id, question_id: question_id, new: true)
+      unless MuteRule.where(user: f).any? { |rule| rule.applies_to? question }
+        Inbox.create(user_id: f.id, question_id: question_id, new: true)
+      end
     end
   rescue StandardError => e
     logger.info "failed to ask question: #{e.message}"

db/migrate/20211222165159_create_mute_rules.rb

@@ -0,0 +1,10 @@
+class CreateMuteRules < ActiveRecord::Migration[5.2]
+  def change
+    create_table :mute_rules do |t|
+      t.references :user, foreign_key: true
+      t.string :muted_phrase
+
+      t.timestamps
+    end
+  end
+end

db/schema.rb

@@ -107,6 +107,14 @@ ActiveRecord::Schema.define(version: 2021_12_28_135426) do
     t.index ["user_id"], name: "index_moderation_votes_on_user_id"
   end
 
+  create_table "mute_rules", force: :cascade do |t|
+    t.bigint "user_id"
+    t.string "muted_phrase"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["user_id"], name: "index_mute_rules_on_user_id"
+  end
+
   create_table "notifications", id: :serial, force: :cascade do |t|
     t.string "target_type"
     t.bigint "target_id"
@@ -306,4 +314,5 @@ ActiveRecord::Schema.define(version: 2021_12_28_135426) do
   end
 
   add_foreign_key "profiles", "users"
+  add_foreign_key "mute_rules", "users"
 end

spec/models/mute_rule_spec.rb

@@ -0,0 +1,13 @@
+require 'rails_helper'
+
+RSpec.describe MuteRule, type: :model do
+  describe "#applies_to?" do
+    let(:user) { FactoryBot.create(:user) }
+    let(:rule) { MuteRule.create(user: user, muted_phrase: "trial") }
+    let(:question) { Question.create(user: user, content: "Did you know that the critically acclaimed MMORPG Final Fantasy XIV has a free trial, and includes the entirety of A Realm Reborn AND the award-winning Heavensward expansion up to level 60 with no restrictions on playtime?") }
+
+    it "only returns true for questions matching a certain phrase" do
+      expect(rule.applies_to?(question)).to be(true)
+    end
+  end
+end

spec/workers/question_worker_spec.rb

@@ -26,5 +26,19 @@ describe QuestionWorker do
             .to(5)
         )
     end
+
+    it "respects mute rules" do
+      question.content = 'Some spicy question text'
+      question.save
+
+      MuteRule.create(user_id: user.followers.first.id, muted_phrase: 'spicy')
+
+      expect { subject }
+        .to(
+          change { Inbox.where(user_id: user.followers.ids, question_id: question_id, new: true).count }
+            .from(0)
+            .to(4)
+        )
+    end
   end
 end