From bce1b6078f4de481e7878d3c1448d6ac75c8dacd Mon Sep 17 00:00:00 2001
From: Max Wofford <max@maxwofford.com>
Date: Wed, 25 Jun 2025 12:29:56 -0400
Subject: [PATCH] Add rack attack (#360)

---
 Gemfile                            |  3 ++
 Gemfile.lock                       |  3 ++
 config/application.rb              |  1 +
 config/initializers/rack_attack.rb | 64 ++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+)
 create mode 100644 config/initializers/rack_attack.rb

diff --git a/Gemfile b/Gemfile
index 9031f67..844cdd8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -57,6 +57,9 @@ gem "thruster", require: false
 # For query count tracking
 gem "query_count"
 
+# Rate limiting
+gem "rack-attack"
+
 # Use Active Storage variants [https://guides.rubyonrails.org/active_storage_overview.html#transforming-images]
 # gem "image_processing", "~> 1.2"
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 221c723..8f0504f 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -346,6 +346,8 @@ GEM
     raabro (1.4.0)
     racc (1.8.1)
     rack (3.1.16)
+    rack-attack (6.7.0)
+      rack (>= 1.0, < 4)
     rack-cors (3.0.0)
       logger
       rack (>= 3.0.14)
@@ -581,6 +583,7 @@ DEPENDENCIES
   propshaft
   puma (>= 5.0)
   query_count
+  rack-attack
   rack-cors
   rack-mini-profiler
   rails (~> 8.0.2)
diff --git a/config/application.rb b/config/application.rb
index 395ea29..8258a84 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -48,5 +48,6 @@ module Harbor
       httponly: true
 
     config.middleware.use HtmlCompressor::Rack
+    config.middleware.use Rack::Attack
   end
 end
diff --git a/config/initializers/rack_attack.rb b/config/initializers/rack_attack.rb
new file mode 100644
index 0000000..d1ff1a7
--- /dev/null
+++ b/config/initializers/rack_attack.rb
@@ -0,0 +1,64 @@
+# config/initializers/rack_attack.rb
+
+class Rack::Attack
+  # Always allow requests from localhost
+  # (blocklist & throttles are skipped)
+  Rack::Attack.safelist("allow from localhost") do |req|
+    # Requests are allowed if the return value is truthy
+    "127.0.0.1" == req.ip || "::1" == req.ip
+  end
+
+  # Allow an IP address to make 5 requests per second
+  throttle("req/ip", limit: 300, period: 5.minutes) do |req|
+    req.ip
+  end
+
+  # Allow an IP address to make 5 POST requests per second
+  throttle("post/ip", limit: 60, period: 5.minutes) do |req|
+    req.ip if req.post?
+  end
+
+  # Throttle requests to /login by IP address
+  throttle("login/ip", limit: 5, period: 20.seconds) do |req|
+    if req.path == "/login" && req.post?
+      req.ip
+    end
+  end
+
+  # Throttle requests to /api by IP address
+  throttle("api/ip", limit: 100, period: 5.minutes) do |req|
+    if req.path.start_with?("/api")
+      req.ip
+    end
+  end
+
+  # Log blocked requests
+  ActiveSupport::Notifications.subscribe(/rack_attack/) do |name, start, finish, request_id, payload|
+    req = payload[:request]
+
+    case name
+    when "rack_attack.throttle"
+      Rails.logger.warn "[Rack::Attack][Throttle] IP: #{req.ip}, Path: #{req.path}, Discriminator: #{payload[:discriminator]}, Matched: #{payload[:matched]}"
+    when "rack_attack.blocklist"
+      Rails.logger.warn "[Rack::Attack][Blocklist] IP: #{req.ip}, Path: #{req.path}, Discriminator: #{payload[:discriminator]}, Matched: #{payload[:matched]}"
+    when "rack_attack.safelist"
+      Rails.logger.info "[Rack::Attack][Safelist] IP: #{req.ip}, Path: #{req.path}, Discriminator: #{payload[:discriminator]}, Matched: #{payload[:matched]}"
+    end
+  end
+
+  # Custom response for throttled requests
+  self.throttled_response = lambda do |env|
+    retry_after = (env["rack.attack.match_data"] || {})[:period]
+    [
+      429,
+      {
+        "Content-Type" => "application/json",
+        "Retry-After" => retry_after.to_s,
+        "X-RateLimit-Limit" => env["rack.attack.matched"].to_s,
+        "X-RateLimit-Remaining" => "0",
+        "X-RateLimit-Reset" => (Time.now + retry_after).to_i.to_s
+      },
+      [ { error: "Too Many Requests", message: "Rate limit exceeded. Try again later." }.to_json ]
+    ]
+  end
+end