Add API docs, limit request per token

Gemfile

@@ -28,6 +28,8 @@ gem 'awesome_print', '1.7.0'
 
 gem 'swagger-docs', '0.2.9'
 
+gem "redis", '3.3.0'
+
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platform: :mri

Gemfile.lock

@@ -115,6 +115,7 @@ GEM
     rb-fsevent (0.9.7)
     rb-inotify (0.9.7)
       ffi (>= 0.5.0)
+    redis (3.3.0)
     rspec-core (3.5.4)
       rspec-support (~> 3.5.0)
     rspec-expectations (3.5.0)
@@ -169,6 +170,7 @@ DEPENDENCIES
   rack-attack (= 5.0.1)
   rack-cors (= 0.4.0)
   rails (~> 5.0.0, >= 5.0.0.1)
+  redis (= 3.3.0)
   rspec-rails (= 3.5.2)
   spring
   spring-watcher-listen (~> 2.0.0)

README.md

@@ -625,6 +625,104 @@ module Api::V1
 end
 ```
 
+## Rate Limiting per token
+#### Create file `config/initializers/throttle.rb`
+```ruby
+# config/initializers/throttle.rb
+
+require "redis"
+
+redis_conf  = YAML.load(File.join(Rails.root, "config", "redis.yml"))
+REDIS = Redis.new(:host => redis_conf["host"], :port => redis_conf["port"])
+
+# We will allow a client a maximum of 60 requests in 15 minutes. The following constants need to be defined in throttle.rb
+THROTTLE_TIME_WINDOW = 15 * 60
+THROTTLE_MAX_REQUESTS = 60
+```
+
+The filter needs to be changed to respond with error messages when the rate limit is exceeded.
+```ruby
+class ApplicationController < ActionController::API
+  include ActionController::Serialization
+  include ActionController::HttpAuthentication::Token::ControllerMethods
+
+  before_action :authenticate
+  before_filter :throttle_token
+
+  protected
+
+  def authenticate
+    authenticate_token || render_unauthorized
+  end
+
+  def authenticate_token
+    authenticate_with_http_token do |token, options|
+      @current_user = User.find_by(api_key: token)
+      @token = token
+    end
+  end
+
+  def render_unauthorized(realm = "Application")
+    self.headers["WWW-Authenticate"] = %(Token realm="#{realm.gsub(/"/, "")}")
+    render json: {message: 'Bad credentials'}, status: :unauthorized
+  end
+
+  def throttle_ip
+    client_ip = request.env["REMOTE_ADDR"]
+    key = "count:#{client_ip}"
+    count = REDIS.get(key)
+
+    unless count
+      REDIS.set(key, 0)
+      REDIS.expire(key, THROTTLE_TIME_WINDOW)
+      return true
+    end
+
+    if count.to_i >= THROTTLE_MAX_REQUESTS
+      render :json => {:message => "You have fired too many requests. Please wait for some time."}, :status => 429
+      return
+    end
+    REDIS.incr(key)
+    true
+  end
+
+  def throttle_token
+    if @token.present?
+      key = "count:#{@token}"
+      count = REDIS.get(key)
+
+      unless count
+        REDIS.set(key, 0)
+        REDIS.expire(key, THROTTLE_TIME_WINDOW)
+        return true
+      end
+
+      if count.to_i >= THROTTLE_MAX_REQUESTS
+        render :json => {:message => "You have fired too many requests. Please wait for some time."}, :status => 429
+        return
+      end
+      REDIS.incr(key)
+      true
+    else
+      false
+    end
+  end
+end
+```
+
+Let’s go ahead and test this `test_throttle.sh`.
+```
+for i in {1..300}
+do
+printf "\n------------------\n"
+echo "Welcome $i times"
+printf "\n"
+# curl -i -H "Authorization: Token token=3Hu9orST5sKDHUPJBwjbogtt" http://localhost:3000/v1/users >> /dev/null
+# curl -i -H "Authorization: Token token=3Hu9orST5sKDHUPJBwjbogtt" http://10.1.0.201:3000/v1/users
+curl -i -H "Authorization: Token token=3Hu9orST5sKDHUPJBwjbogtt" http://localhost:3000/v1/users
+done
+```
+
 ## How to run
 *Clone source from github: `[email protected]:ntamvl/rails_5_api_tutorial.git`*
 ```
@@ -674,3 +772,10 @@ Now you have the keys to the castle, and all the basics for building an API the
 Hopefully then guide was helpful for you, and if you want any points clarified or just want to say thanks then feel free to use the comments below.
 
 Cheers, and happy coding!
+
+---------------------------------------------
+Redis documentation for INCR command. [return]
+redis - A Ruby client that tries to match Redis’ API one-to-one, while still providing an idiomatic interface. It features thread-safety, client-side sharding, pipelining, and an obsession for performance. [return]
+Rails’ before filter. [return]
+IETF: Additional HTTP Status Codes - 429 Too Many Requests. [return]
+*If you have questions or comments about this blog post, you can get in touch with me on Twitter @nguyentamvn*

app/controllers/application_controller.rb

@@ -3,6 +3,7 @@ class ApplicationController < ActionController::API
   include ActionController::HttpAuthentication::Token::ControllerMethods
 
   before_action :authenticate
+  before_filter :throttle_token
 
   protected
 
@@ -13,12 +14,54 @@ def authenticate
   def authenticate_token
     authenticate_with_http_token do |token, options|
       @current_user = User.find_by(api_key: token)
+      @token = token
     end
   end
 
   def render_unauthorized(realm = "Application")
     self.headers["WWW-Authenticate"] = %(Token realm="#{realm.gsub(/"/, "")}")
-    render json: 'Bad credentials', status: :unauthorized
+    render json: {message: 'Bad credentials'}, status: :unauthorized
+  end
+
+  def throttle_ip
+    client_ip = request.env["REMOTE_ADDR"]
+    key = "count:#{client_ip}"
+    count = REDIS.get(key)
+
+    unless count
+      REDIS.set(key, 0)
+      REDIS.expire(key, THROTTLE_TIME_WINDOW)
+      return true
+    end
+
+    if count.to_i >= THROTTLE_MAX_REQUESTS
+      render :json => {:message => "You have fired too many requests. Please wait for some time."}, :status => 429
+      return
+    end
+    REDIS.incr(key)
+    true
+  end
+
+  def throttle_token
+    if @token.present?
+      key = "count:#{@token}"
+      count = REDIS.get(key)
+
+      unless count
+        REDIS.set(key, 0)
+        REDIS.expire(key, THROTTLE_TIME_WINDOW)
+        return true
+      end
+
+      if count.to_i >= THROTTLE_MAX_REQUESTS
+        render :json => {:message => "You have fired too many requests. Please wait for some time."}, :status => 429
+        return
+      end
+      REDIS.incr(key)
+      true
+    else
+      false
+    end
   end
 
 end

config/initializers/rack_attack.rb

@@ -9,8 +9,8 @@ class Rack::Attack
     '127.0.0.1' == req.ip || '::1' == req.ip
   end
 
-  # Allow an IP address to make 5 requests every 5 seconds
-  throttle('req/ip', limit: 5, period: 5) do |req|
+  # Allow an IP address to make 100 requests every 5 seconds
+  throttle('req/ip', limit: 100, period: 5) do |req|
     req.ip
   end
 
@@ -20,7 +20,7 @@ class Rack::Attack
     [
       429,
       {'Content-Type' => 'application/json', 'Retry-After' => retry_after.to_s},
-      [{error: "Throttle limit reached. Retry later."}.to_json]
+      [{error: "Throttle limit reached. Retry later.", status: 429}.to_json]
     ]
   }
 end

config/initializers/throttle.rb

@@ -0,0 +1,7 @@
+require "redis"
+
+redis_conf  = YAML.load(File.join(Rails.root, "config", "redis.yml"))
+REDIS = Redis.new(:host => redis_conf["host"], :port => redis_conf["port"])
+
+THROTTLE_TIME_WINDOW = 15 * 60
+THROTTLE_MAX_REQUESTS = 60

config/redis.yml

@@ -0,0 +1,2 @@
+host: localhost
+port: 6379

test_throttle.sh

@@ -0,0 +1,9 @@
+for i in {1..300}
+do
+printf "\n------------------\n"
+echo "Welcome $i times"
+printf "\n"
+# curl -i -H "Authorization: Token token=3Hu9orST5sKDHUPJBwjbogtt" http://localhost:3000/v1/users >> /dev/null
+# curl -i -H "Authorization: Token token=3Hu9orST5sKDHUPJBwjbogtt" http://10.1.0.201:3000/v1/users
+curl -i -H "Authorization: Token token=3Hu9orST5sKDHUPJBwjbogtt" http://localhost:3000/v1/users
+done